From ebd9779683aaf089ad0173862553cdd3288ad9b4 Mon Sep 17 00:00:00 2001
From: Justin Stitt <justinstitt@google.com>
Date: Thu, 28 Mar 2024 21:44:48 +0000
Subject: smb: client: replace deprecated strncpy with strscpy

strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

In cifssmb.c:
Using strncpy with a length argument equal to strlen(src) is generally
dangerous because it can cause string buffers to not be NUL-terminated.
In this case, however, there was extra effort made to ensure the buffer
was NUL-terminated via a manual NUL-byte assignment. In an effort to rid
the kernel of strncpy() use, let's swap over to using strscpy() which
guarantees NUL-termination on the destination buffer.

To handle the case where ea_name is NULL, let's use the ?: operator to
substitute in an empty string, thereby allowing strscpy to still
NUL-terminate the destintation string.

Interesting note: this flex array buffer may go on to also have some
value encoded after the NUL-termination:
|	if (ea_value_len)
|		memcpy(parm_data->list.name + name_len + 1,
|			ea_value, ea_value_len);

Now for smb2ops.c and smb2transport.c:
Both of these cases are simple, strncpy() is used to copy string
literals which have a length less than the destination buffer's size. We
can simply swap in the new 2-argument version of strscpy() introduced in
Commit e6584c3964f2f ("string: Allow 2-argument strscpy()").

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/cifssmb.c       | 6 ++----
 fs/smb/client/smb2ops.c       | 2 +-
 fs/smb/client/smb2transport.c | 2 +-
 3 files changed, 4 insertions(+), 6 deletions(-)

(limited to 'fs')

diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c
index 5aee555515730..23b5709ddc311 100644
--- a/fs/smb/client/cifssmb.c
+++ b/fs/smb/client/cifssmb.c
@@ -5854,10 +5854,8 @@ SetEARetry:
 	parm_data->list.EA_flags = 0;
 	/* we checked above that name len is less than 255 */
 	parm_data->list.name_len = (__u8)name_len;
-	/* EA names are always ASCII */
-	if (ea_name)
-		strncpy(parm_data->list.name, ea_name, name_len);
-	parm_data->list.name[name_len] = '\0';
+	/* EA names are always ASCII and NUL-terminated */
+	strscpy(parm_data->list.name, ea_name ?: "", name_len + 1);
 	parm_data->list.value_len = cpu_to_le16(ea_value_len);
 	/* caller ensures that ea_value_len is less than 64K but
 	we need to ensure that it fits within the smb */
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 2ed456948f34c..35bf7eb315cdf 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -3913,7 +3913,7 @@ smb21_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
 		strcat(message, "W");
 	}
 	if (!new_oplock)
-		strncpy(message, "None", sizeof(message));
+		strscpy(message, "None");
 
 	cinode->oplock = new_oplock;
 	cifs_dbg(FYI, "%s Lease granted on inode %p\n", message,
diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c
index 5a3ca62d2f07f..1d6e54f7879e6 100644
--- a/fs/smb/client/smb2transport.c
+++ b/fs/smb/client/smb2transport.c
@@ -659,7 +659,7 @@ smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 	}
 	spin_unlock(&server->srv_lock);
 	if (!is_binding && !server->session_estab) {
-		strncpy(shdr->Signature, "BSRSPYL", 8);
+		strscpy(shdr->Signature, "BSRSPYL");
 		return 0;
 	}
 
-- 
cgit 1.2.3-korg


From 24a9799aa8efecd0eb55a75e35f9d8e6400063aa Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Mon, 1 Apr 2024 14:13:10 -0300
Subject: smb: client: fix UAF in smb2_reconnect_server()

The UAF bug is due to smb2_reconnect_server() accessing a session that
is already being teared down by another thread that is executing
__cifs_put_smb_ses().  This can happen when (a) the client has
connection to the server but no session or (b) another thread ends up
setting @ses->ses_status again to something different than
SES_EXITING.

To fix this, we need to make sure to unconditionally set
@ses->ses_status to SES_EXITING and prevent any other threads from
setting a new status while we're still tearing it down.

The following can be reproduced by adding some delay to right after
the ipc is freed in __cifs_put_smb_ses() - which will give
smb2_reconnect_server() worker a chance to run and then accessing
@ses->ipc:

kinit ...
mount.cifs //srv/share /mnt/1 -o sec=krb5,nohandlecache,echo_interval=10
[disconnect srv]
ls /mnt/1 &>/dev/null
sleep 30
kdestroy
[reconnect srv]
sleep 10
umount /mnt/1
...
CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed
CIFS: VFS: \\srv Send error in SessSetup = -126
CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed
CIFS: VFS: \\srv Send error in SessSetup = -126
general protection fault, probably for non-canonical address
0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI
CPU: 3 PID: 50 Comm: kworker/3:1 Not tainted 6.9.0-rc2 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39
04/01/2014
Workqueue: cifsiod smb2_reconnect_server [cifs]
RIP: 0010:__list_del_entry_valid_or_report+0x33/0xf0
Code: 4f 08 48 85 d2 74 42 48 85 c9 74 59 48 b8 00 01 00 00 00 00 ad
de 48 39 c2 74 61 48 b8 22 01 00 00 00 00 74 69 <48> 8b 01 48 39 f8 75
7b 48 8b 72 08 48 39 c6 0f 85 88 00 00 00 b8
RSP: 0018:ffffc900001bfd70 EFLAGS: 00010a83
RAX: dead000000000122 RBX: ffff88810da53838 RCX: 6b6b6b6b6b6b6b6b
RDX: 6b6b6b6b6b6b6b6b RSI: ffffffffc02f6878 RDI: ffff88810da53800
RBP: ffff88810da53800 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88810c064000
R13: 0000000000000001 R14: ffff88810c064000 R15: ffff8881039cc000
FS: 0000000000000000(0000) GS:ffff888157c00000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe3728b1000 CR3: 000000010caa4000 CR4: 0000000000750ef0
PKRU: 55555554
Call Trace:
 <TASK>
 ? die_addr+0x36/0x90
 ? exc_general_protection+0x1c1/0x3f0
 ? asm_exc_general_protection+0x26/0x30
 ? __list_del_entry_valid_or_report+0x33/0xf0
 __cifs_put_smb_ses+0x1ae/0x500 [cifs]
 smb2_reconnect_server+0x4ed/0x710 [cifs]
 process_one_work+0x205/0x6b0
 worker_thread+0x191/0x360
 ? __pfx_worker_thread+0x10/0x10
 kthread+0xe2/0x110
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x34/0x50
 ? __pfx_kthread+0x10/0x10
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/connect.c | 83 ++++++++++++++++++++-----------------------------
 1 file changed, 34 insertions(+), 49 deletions(-)

(limited to 'fs')

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index 9b85b5341822e..ee29bc57300cd 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -232,7 +232,13 @@ cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server,
 
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry_safe(ses, nses, &pserver->smb_ses_list, smb_ses_list) {
-		/* check if iface is still active */
+		spin_lock(&ses->ses_lock);
+		if (ses->ses_status == SES_EXITING) {
+			spin_unlock(&ses->ses_lock);
+			continue;
+		}
+		spin_unlock(&ses->ses_lock);
+
 		spin_lock(&ses->chan_lock);
 		if (cifs_ses_get_chan_index(ses, server) ==
 		    CIFS_INVAL_CHAN_INDEX) {
@@ -1963,31 +1969,6 @@ out:
 	return rc;
 }
 
-/**
- * cifs_free_ipc - helper to release the session IPC tcon
- * @ses: smb session to unmount the IPC from
- *
- * Needs to be called everytime a session is destroyed.
- *
- * On session close, the IPC is closed and the server must release all tcons of the session.
- * No need to send a tree disconnect here.
- *
- * Besides, it will make the server to not close durable and resilient files on session close, as
- * specified in MS-SMB2 3.3.5.6 Receiving an SMB2 LOGOFF Request.
- */
-static int
-cifs_free_ipc(struct cifs_ses *ses)
-{
-	struct cifs_tcon *tcon = ses->tcon_ipc;
-
-	if (tcon == NULL)
-		return 0;
-
-	tconInfoFree(tcon);
-	ses->tcon_ipc = NULL;
-	return 0;
-}
-
 static struct cifs_ses *
 cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
 {
@@ -2019,48 +2000,52 @@ cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
 void __cifs_put_smb_ses(struct cifs_ses *ses)
 {
 	struct TCP_Server_Info *server = ses->server;
+	struct cifs_tcon *tcon;
 	unsigned int xid;
 	size_t i;
+	bool do_logoff;
 	int rc;
 
+	spin_lock(&cifs_tcp_ses_lock);
 	spin_lock(&ses->ses_lock);
-	if (ses->ses_status == SES_EXITING) {
+	cifs_dbg(FYI, "%s: id=0x%llx ses_count=%d ses_status=%u ipc=%s\n",
+		 __func__, ses->Suid, ses->ses_count, ses->ses_status,
+		 ses->tcon_ipc ? ses->tcon_ipc->tree_name : "none");
+	if (ses->ses_status == SES_EXITING || --ses->ses_count > 0) {
 		spin_unlock(&ses->ses_lock);
+		spin_unlock(&cifs_tcp_ses_lock);
 		return;
 	}
-	spin_unlock(&ses->ses_lock);
+	/* ses_count can never go negative */
+	WARN_ON(ses->ses_count < 0);
 
-	cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
-	cifs_dbg(FYI,
-		 "%s: ses ipc: %s\n", __func__, ses->tcon_ipc ? ses->tcon_ipc->tree_name : "NONE");
+	spin_lock(&ses->chan_lock);
+	cifs_chan_clear_need_reconnect(ses, server);
+	spin_unlock(&ses->chan_lock);
 
-	spin_lock(&cifs_tcp_ses_lock);
-	if (--ses->ses_count > 0) {
-		spin_unlock(&cifs_tcp_ses_lock);
-		return;
-	}
-	spin_lock(&ses->ses_lock);
-	if (ses->ses_status == SES_GOOD)
-		ses->ses_status = SES_EXITING;
+	do_logoff = ses->ses_status == SES_GOOD && server->ops->logoff;
+	ses->ses_status = SES_EXITING;
+	tcon = ses->tcon_ipc;
+	ses->tcon_ipc = NULL;
 	spin_unlock(&ses->ses_lock);
 	spin_unlock(&cifs_tcp_ses_lock);
 
-	/* ses_count can never go negative */
-	WARN_ON(ses->ses_count < 0);
-
-	spin_lock(&ses->ses_lock);
-	if (ses->ses_status == SES_EXITING && server->ops->logoff) {
-		spin_unlock(&ses->ses_lock);
-		cifs_free_ipc(ses);
+	/*
+	 * On session close, the IPC is closed and the server must release all
+	 * tcons of the session.  No need to send a tree disconnect here.
+	 *
+	 * Besides, it will make the server to not close durable and resilient
+	 * files on session close, as specified in MS-SMB2 3.3.5.6 Receiving an
+	 * SMB2 LOGOFF Request.
+	 */
+	tconInfoFree(tcon);
+	if (do_logoff) {
 		xid = get_xid();
 		rc = server->ops->logoff(xid, ses);
 		if (rc)
 			cifs_server_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
 				__func__, rc);
 		_free_xid(xid);
-	} else {
-		spin_unlock(&ses->ses_lock);
-		cifs_free_ipc(ses);
 	}
 
 	spin_lock(&cifs_tcp_ses_lock);
-- 
cgit 1.2.3-korg


From e9e62243a3e2322cf639f653a0b0a88a76446ce7 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Tue, 2 Apr 2024 10:11:35 +0100
Subject: cifs: Fix caching to try to do open O_WRONLY as rdwr on server

When we're engaged in local caching of a cifs filesystem, we cannot perform
caching of a partially written cache granule unless we can read the rest of
the granule.  This can result in unexpected access errors being reported to
the user.

Fix this by the following: if a file is opened O_WRONLY locally, but the
mount was given the "-o fsc" flag, try first opening the remote file with
GENERIC_READ|GENERIC_WRITE and if that returns -EACCES, try dropping the
GENERIC_READ and doing the open again.  If that last succeeds, invalidate
the cache for that file as for O_DIRECT.

Fixes: 70431bfd825d ("cifs: Support fscache indexing rewrite")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/dir.c     | 15 +++++++++++++++
 fs/smb/client/file.c    | 48 ++++++++++++++++++++++++++++++++++++++----------
 fs/smb/client/fscache.h |  6 ++++++
 3 files changed, 59 insertions(+), 10 deletions(-)

(limited to 'fs')

diff --git a/fs/smb/client/dir.c b/fs/smb/client/dir.c
index d11dc3aa458ba..864b194dbaa0a 100644
--- a/fs/smb/client/dir.c
+++ b/fs/smb/client/dir.c
@@ -189,6 +189,7 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
 	int disposition;
 	struct TCP_Server_Info *server = tcon->ses->server;
 	struct cifs_open_parms oparms;
+	int rdwr_for_fscache = 0;
 
 	*oplock = 0;
 	if (tcon->ses->server->oplocks)
@@ -200,6 +201,10 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
 		return PTR_ERR(full_path);
 	}
 
+	/* If we're caching, we need to be able to fill in around partial writes. */
+	if (cifs_fscache_enabled(inode) && (oflags & O_ACCMODE) == O_WRONLY)
+		rdwr_for_fscache = 1;
+
 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
 	if (tcon->unix_ext && cap_unix(tcon->ses) && !tcon->broken_posix_open &&
 	    (CIFS_UNIX_POSIX_PATH_OPS_CAP &
@@ -276,6 +281,8 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
 		desired_access |= GENERIC_READ; /* is this too little? */
 	if (OPEN_FMODE(oflags) & FMODE_WRITE)
 		desired_access |= GENERIC_WRITE;
+	if (rdwr_for_fscache == 1)
+		desired_access |= GENERIC_READ;
 
 	disposition = FILE_OVERWRITE_IF;
 	if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
@@ -304,6 +311,7 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
 	if (!tcon->unix_ext && (mode & S_IWUGO) == 0)
 		create_options |= CREATE_OPTION_READONLY;
 
+retry_open:
 	oparms = (struct cifs_open_parms) {
 		.tcon = tcon,
 		.cifs_sb = cifs_sb,
@@ -317,8 +325,15 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
 	rc = server->ops->open(xid, &oparms, oplock, buf);
 	if (rc) {
 		cifs_dbg(FYI, "cifs_create returned 0x%x\n", rc);
+		if (rc == -EACCES && rdwr_for_fscache == 1) {
+			desired_access &= ~GENERIC_READ;
+			rdwr_for_fscache = 2;
+			goto retry_open;
+		}
 		goto out;
 	}
+	if (rdwr_for_fscache == 2)
+		cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);
 
 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
 	/*
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index 16aadce492b2e..ab536ce8a04a5 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -206,12 +206,12 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon)
 	 */
 }
 
-static inline int cifs_convert_flags(unsigned int flags)
+static inline int cifs_convert_flags(unsigned int flags, int rdwr_for_fscache)
 {
 	if ((flags & O_ACCMODE) == O_RDONLY)
 		return GENERIC_READ;
 	else if ((flags & O_ACCMODE) == O_WRONLY)
-		return GENERIC_WRITE;
+		return rdwr_for_fscache == 1 ? (GENERIC_READ | GENERIC_WRITE) : GENERIC_WRITE;
 	else if ((flags & O_ACCMODE) == O_RDWR) {
 		/* GENERIC_ALL is too much permission to request
 		   can cause unnecessary access denied on create */
@@ -348,11 +348,16 @@ static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_
 	int create_options = CREATE_NOT_DIR;
 	struct TCP_Server_Info *server = tcon->ses->server;
 	struct cifs_open_parms oparms;
+	int rdwr_for_fscache = 0;
 
 	if (!server->ops->open)
 		return -ENOSYS;
 
-	desired_access = cifs_convert_flags(f_flags);
+	/* If we're caching, we need to be able to fill in around partial writes. */
+	if (cifs_fscache_enabled(inode) && (f_flags & O_ACCMODE) == O_WRONLY)
+		rdwr_for_fscache = 1;
+
+	desired_access = cifs_convert_flags(f_flags, rdwr_for_fscache);
 
 /*********************************************************************
  *  open flag mapping table:
@@ -389,6 +394,7 @@ static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_
 	if (f_flags & O_DIRECT)
 		create_options |= CREATE_NO_BUFFER;
 
+retry_open:
 	oparms = (struct cifs_open_parms) {
 		.tcon = tcon,
 		.cifs_sb = cifs_sb,
@@ -400,8 +406,16 @@ static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_
 	};
 
 	rc = server->ops->open(xid, &oparms, oplock, buf);
-	if (rc)
+	if (rc) {
+		if (rc == -EACCES && rdwr_for_fscache == 1) {
+			desired_access = cifs_convert_flags(f_flags, 0);
+			rdwr_for_fscache = 2;
+			goto retry_open;
+		}
 		return rc;
+	}
+	if (rdwr_for_fscache == 2)
+		cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);
 
 	/* TODO: Add support for calling posix query info but with passing in fid */
 	if (tcon->unix_ext)
@@ -834,11 +848,11 @@ int cifs_open(struct inode *inode, struct file *file)
 use_cache:
 	fscache_use_cookie(cifs_inode_cookie(file_inode(file)),
 			   file->f_mode & FMODE_WRITE);
-	if (file->f_flags & O_DIRECT &&
-	    (!((file->f_flags & O_ACCMODE) != O_RDONLY) ||
-	     file->f_flags & O_APPEND))
-		cifs_invalidate_cache(file_inode(file),
-				      FSCACHE_INVAL_DIO_WRITE);
+	if (!(file->f_flags & O_DIRECT))
+		goto out;
+	if ((file->f_flags & (O_ACCMODE | O_APPEND)) == O_RDONLY)
+		goto out;
+	cifs_invalidate_cache(file_inode(file), FSCACHE_INVAL_DIO_WRITE);
 
 out:
 	free_dentry_path(page);
@@ -903,6 +917,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 	int disposition = FILE_OPEN;
 	int create_options = CREATE_NOT_DIR;
 	struct cifs_open_parms oparms;
+	int rdwr_for_fscache = 0;
 
 	xid = get_xid();
 	mutex_lock(&cfile->fh_mutex);
@@ -966,7 +981,11 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 	}
 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
 
-	desired_access = cifs_convert_flags(cfile->f_flags);
+	/* If we're caching, we need to be able to fill in around partial writes. */
+	if (cifs_fscache_enabled(inode) && (cfile->f_flags & O_ACCMODE) == O_WRONLY)
+		rdwr_for_fscache = 1;
+
+	desired_access = cifs_convert_flags(cfile->f_flags, rdwr_for_fscache);
 
 	/* O_SYNC also has bit for O_DSYNC so following check picks up either */
 	if (cfile->f_flags & O_SYNC)
@@ -978,6 +997,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 	if (server->ops->get_lease_key)
 		server->ops->get_lease_key(inode, &cfile->fid);
 
+retry_open:
 	oparms = (struct cifs_open_parms) {
 		.tcon = tcon,
 		.cifs_sb = cifs_sb,
@@ -1003,6 +1023,11 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 		/* indicate that we need to relock the file */
 		oparms.reconnect = true;
 	}
+	if (rc == -EACCES && rdwr_for_fscache == 1) {
+		desired_access = cifs_convert_flags(cfile->f_flags, 0);
+		rdwr_for_fscache = 2;
+		goto retry_open;
+	}
 
 	if (rc) {
 		mutex_unlock(&cfile->fh_mutex);
@@ -1011,6 +1036,9 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 		goto reopen_error_exit;
 	}
 
+	if (rdwr_for_fscache == 2)
+		cifs_invalidate_cache(inode, FSCACHE_INVAL_DIO_WRITE);
+
 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
 reopen_success:
 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
diff --git a/fs/smb/client/fscache.h b/fs/smb/client/fscache.h
index a3d73720914f8..1f2ea9f5cc9a8 100644
--- a/fs/smb/client/fscache.h
+++ b/fs/smb/client/fscache.h
@@ -109,6 +109,11 @@ static inline void cifs_readahead_to_fscache(struct inode *inode,
 		__cifs_readahead_to_fscache(inode, pos, len);
 }
 
+static inline bool cifs_fscache_enabled(struct inode *inode)
+{
+	return fscache_cookie_enabled(cifs_inode_cookie(inode));
+}
+
 #else /* CONFIG_CIFS_FSCACHE */
 static inline
 void cifs_fscache_fill_coherency(struct inode *inode,
@@ -124,6 +129,7 @@ static inline void cifs_fscache_release_inode_cookie(struct inode *inode) {}
 static inline void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update) {}
 static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode) { return NULL; }
 static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags) {}
+static inline bool cifs_fscache_enabled(struct inode *inode) { return false; }
 
 static inline int cifs_fscache_query_occupancy(struct inode *inode,
 					       pgoff_t first, unsigned int nr_pages,
-- 
cgit 1.2.3-korg


From 062a7f0ff46eb57aff526897bd2bebfdb1d3046a Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Mon, 1 Apr 2024 22:37:42 -0500
Subject: smb: client: guarantee refcounted children from parent session

Avoid potential use-after-free bugs when walking DFS referrals,
mounting and performing DFS failover by ensuring that all children
from parent @tcon->ses are also refcounted.  They're all needed across
the entire DFS mount.  Get rid of @tcon->dfs_ses_list while we're at
it, too.

Cc: stable@vger.kernel.org # 6.4+
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404021527.ZlRkIxgv-lkp@intel.com/
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/cifsglob.h  |  2 --
 fs/smb/client/cifsproto.h | 20 +++++++++----------
 fs/smb/client/connect.c   | 25 ++++++++++++++++++-----
 fs/smb/client/dfs.c       | 51 ++++++++++++++++++++++-------------------------
 fs/smb/client/dfs.h       | 33 +++++++++++++++++++-----------
 fs/smb/client/dfs_cache.c | 11 +---------
 fs/smb/client/misc.c      |  6 ------
 7 files changed, 76 insertions(+), 72 deletions(-)

(limited to 'fs')

diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 7ed9d05f6890b..286afbe346be0 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1281,7 +1281,6 @@ struct cifs_tcon {
 	struct cached_fids *cfids;
 	/* BB add field for back pointer to sb struct(s)? */
 #ifdef CONFIG_CIFS_DFS_UPCALL
-	struct list_head dfs_ses_list;
 	struct delayed_work dfs_cache_work;
 #endif
 	struct delayed_work	query_interfaces; /* query interfaces workqueue job */
@@ -1804,7 +1803,6 @@ struct cifs_mount_ctx {
 	struct TCP_Server_Info *server;
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon;
-	struct list_head dfs_ses_list;
 };
 
 static inline void __free_dfs_info_param(struct dfs_info3_param *param)
diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h
index 0723e1b57256b..8e0a348f1f660 100644
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -725,31 +725,31 @@ struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon);
 void cifs_put_tcon_super(struct super_block *sb);
 int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry);
 
-/* Put references of @ses and @ses->dfs_root_ses */
+/* Put references of @ses and its children */
 static inline void cifs_put_smb_ses(struct cifs_ses *ses)
 {
-	struct cifs_ses *rses = ses->dfs_root_ses;
+	struct cifs_ses *next;
 
-	__cifs_put_smb_ses(ses);
-	if (rses)
-		__cifs_put_smb_ses(rses);
+	do {
+		next = ses->dfs_root_ses;
+		__cifs_put_smb_ses(ses);
+	} while ((ses = next));
 }
 
-/* Get an active reference of @ses and @ses->dfs_root_ses.
+/* Get an active reference of @ses and its children.
  *
  * NOTE: make sure to call this function when incrementing reference count of
  * @ses to ensure that any DFS root session attached to it (@ses->dfs_root_ses)
  * will also get its reference count incremented.
  *
- * cifs_put_smb_ses() will put both references, so call it when you're done.
+ * cifs_put_smb_ses() will put all references, so call it when you're done.
  */
 static inline void cifs_smb_ses_inc_refcount(struct cifs_ses *ses)
 {
 	lockdep_assert_held(&cifs_tcp_ses_lock);
 
-	ses->ses_count++;
-	if (ses->dfs_root_ses)
-		ses->dfs_root_ses->ses_count++;
+	for (; ses; ses = ses->dfs_root_ses)
+		ses->ses_count++;
 }
 
 static inline bool dfs_src_pathname_equal(const char *s1, const char *s2)
diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index ee29bc57300cd..38b75cfa06e3e 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -1866,6 +1866,9 @@ static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
 	    ctx->sectype != ses->sectype)
 		return 0;
 
+	if (ctx->dfs_root_ses != ses->dfs_root_ses)
+		return 0;
+
 	/*
 	 * If an existing session is limited to less channels than
 	 * requested, it should not be reused
@@ -2358,9 +2361,9 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
 	 * need to lock before changing something in the session.
 	 */
 	spin_lock(&cifs_tcp_ses_lock);
+	if (ctx->dfs_root_ses)
+		cifs_smb_ses_inc_refcount(ctx->dfs_root_ses);
 	ses->dfs_root_ses = ctx->dfs_root_ses;
-	if (ses->dfs_root_ses)
-		ses->dfs_root_ses->ses_count++;
 	list_add(&ses->smb_ses_list, &server->smb_ses_list);
 	spin_unlock(&cifs_tcp_ses_lock);
 
@@ -3311,6 +3314,9 @@ void cifs_mount_put_conns(struct cifs_mount_ctx *mnt_ctx)
 		cifs_put_smb_ses(mnt_ctx->ses);
 	else if (mnt_ctx->server)
 		cifs_put_tcp_session(mnt_ctx->server, 0);
+	mnt_ctx->ses = NULL;
+	mnt_ctx->tcon = NULL;
+	mnt_ctx->server = NULL;
 	mnt_ctx->cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
 	free_xid(mnt_ctx->xid);
 }
@@ -3589,8 +3595,6 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
 	bool isdfs;
 	int rc;
 
-	INIT_LIST_HEAD(&mnt_ctx.dfs_ses_list);
-
 	rc = dfs_mount_share(&mnt_ctx, &isdfs);
 	if (rc)
 		goto error;
@@ -3621,7 +3625,6 @@ out:
 	return rc;
 
 error:
-	dfs_put_root_smb_sessions(&mnt_ctx.dfs_ses_list);
 	cifs_mount_put_conns(&mnt_ctx);
 	return rc;
 }
@@ -3636,6 +3639,18 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
 		goto error;
 
 	rc = cifs_mount_get_tcon(&mnt_ctx);
+	if (!rc) {
+		/*
+		 * Prevent superblock from being created with any missing
+		 * connections.
+		 */
+		if (WARN_ON(!mnt_ctx.server))
+			rc = -EHOSTDOWN;
+		else if (WARN_ON(!mnt_ctx.ses))
+			rc = -EACCES;
+		else if (WARN_ON(!mnt_ctx.tcon))
+			rc = -ENOENT;
+	}
 	if (rc)
 		goto error;
 
diff --git a/fs/smb/client/dfs.c b/fs/smb/client/dfs.c
index 449c59830039b..3ec965547e3d4 100644
--- a/fs/smb/client/dfs.c
+++ b/fs/smb/client/dfs.c
@@ -66,33 +66,20 @@ static int get_session(struct cifs_mount_ctx *mnt_ctx, const char *full_path)
 }
 
 /*
- * Track individual DFS referral servers used by new DFS mount.
- *
- * On success, their lifetime will be shared by final tcon (dfs_ses_list).
- * Otherwise, they will be put by dfs_put_root_smb_sessions() in cifs_mount().
+ * Get an active reference of @ses so that next call to cifs_put_tcon() won't
+ * release it as any new DFS referrals must go through its IPC tcon.
  */
-static int add_root_smb_session(struct cifs_mount_ctx *mnt_ctx)
+static void add_root_smb_session(struct cifs_mount_ctx *mnt_ctx)
 {
 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
-	struct dfs_root_ses *root_ses;
 	struct cifs_ses *ses = mnt_ctx->ses;
 
 	if (ses) {
-		root_ses = kmalloc(sizeof(*root_ses), GFP_KERNEL);
-		if (!root_ses)
-			return -ENOMEM;
-
-		INIT_LIST_HEAD(&root_ses->list);
-
 		spin_lock(&cifs_tcp_ses_lock);
 		cifs_smb_ses_inc_refcount(ses);
 		spin_unlock(&cifs_tcp_ses_lock);
-		root_ses->ses = ses;
-		list_add_tail(&root_ses->list, &mnt_ctx->dfs_ses_list);
 	}
-	/* Select new DFS referral server so that new referrals go through it */
 	ctx->dfs_root_ses = ses;
-	return 0;
 }
 
 static inline int parse_dfs_target(struct smb3_fs_context *ctx,
@@ -185,11 +172,8 @@ again:
 					continue;
 			}
 
-			if (is_refsrv) {
-				rc = add_root_smb_session(mnt_ctx);
-				if (rc)
-					goto out;
-			}
+			if (is_refsrv)
+				add_root_smb_session(mnt_ctx);
 
 			rc = ref_walk_advance(rw);
 			if (!rc) {
@@ -232,6 +216,7 @@ static int __dfs_mount_share(struct cifs_mount_ctx *mnt_ctx)
 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
 	struct cifs_tcon *tcon;
 	char *origin_fullpath;
+	bool new_tcon = true;
 	int rc;
 
 	origin_fullpath = dfs_get_path(cifs_sb, ctx->source);
@@ -239,6 +224,18 @@ static int __dfs_mount_share(struct cifs_mount_ctx *mnt_ctx)
 		return PTR_ERR(origin_fullpath);
 
 	rc = dfs_referral_walk(mnt_ctx);
+	if (!rc) {
+		/*
+		 * Prevent superblock from being created with any missing
+		 * connections.
+		 */
+		if (WARN_ON(!mnt_ctx->server))
+			rc = -EHOSTDOWN;
+		else if (WARN_ON(!mnt_ctx->ses))
+			rc = -EACCES;
+		else if (WARN_ON(!mnt_ctx->tcon))
+			rc = -ENOENT;
+	}
 	if (rc)
 		goto out;
 
@@ -247,15 +244,14 @@ static int __dfs_mount_share(struct cifs_mount_ctx *mnt_ctx)
 	if (!tcon->origin_fullpath) {
 		tcon->origin_fullpath = origin_fullpath;
 		origin_fullpath = NULL;
+	} else {
+		new_tcon = false;
 	}
 	spin_unlock(&tcon->tc_lock);
 
-	if (list_empty(&tcon->dfs_ses_list)) {
-		list_replace_init(&mnt_ctx->dfs_ses_list, &tcon->dfs_ses_list);
+	if (new_tcon) {
 		queue_delayed_work(dfscache_wq, &tcon->dfs_cache_work,
 				   dfs_cache_get_ttl() * HZ);
-	} else {
-		dfs_put_root_smb_sessions(&mnt_ctx->dfs_ses_list);
 	}
 
 out:
@@ -298,7 +294,6 @@ int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs)
 	if (rc)
 		return rc;
 
-	ctx->dfs_root_ses = mnt_ctx->ses;
 	/*
 	 * If called with 'nodfs' mount option, then skip DFS resolving.  Otherwise unconditionally
 	 * try to get an DFS referral (even cached) to determine whether it is an DFS mount.
@@ -324,7 +319,9 @@ int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs)
 
 	*isdfs = true;
 	add_root_smb_session(mnt_ctx);
-	return __dfs_mount_share(mnt_ctx);
+	rc = __dfs_mount_share(mnt_ctx);
+	dfs_put_root_smb_sessions(mnt_ctx);
+	return rc;
 }
 
 /* Update dfs referral path of superblock */
diff --git a/fs/smb/client/dfs.h b/fs/smb/client/dfs.h
index 875ab7ae57fcd..e5c4dcf837503 100644
--- a/fs/smb/client/dfs.h
+++ b/fs/smb/client/dfs.h
@@ -7,7 +7,9 @@
 #define _CIFS_DFS_H
 
 #include "cifsglob.h"
+#include "cifsproto.h"
 #include "fs_context.h"
+#include "dfs_cache.h"
 #include "cifs_unicode.h"
 #include <linux/namei.h>
 
@@ -114,11 +116,6 @@ static inline void ref_walk_set_tgt_hint(struct dfs_ref_walk *rw)
 				       ref_walk_tit(rw));
 }
 
-struct dfs_root_ses {
-	struct list_head list;
-	struct cifs_ses *ses;
-};
-
 int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref,
 			      struct smb3_fs_context *ctx);
 int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs);
@@ -133,20 +130,32 @@ static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx, const char *p
 {
 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
 	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct cifs_ses *rses = ctx->dfs_root_ses ?: mnt_ctx->ses;
 
-	return dfs_cache_find(mnt_ctx->xid, ctx->dfs_root_ses, cifs_sb->local_nls,
+	return dfs_cache_find(mnt_ctx->xid, rses, cifs_sb->local_nls,
 			      cifs_remap(cifs_sb), path, ref, tl);
 }
 
-static inline void dfs_put_root_smb_sessions(struct list_head *head)
+/*
+ * cifs_get_smb_ses() already guarantees an active reference of
+ * @ses->dfs_root_ses when a new session is created, so we need to put extra
+ * references of all DFS root sessions that were used across the mount process
+ * in dfs_mount_share().
+ */
+static inline void dfs_put_root_smb_sessions(struct cifs_mount_ctx *mnt_ctx)
 {
-	struct dfs_root_ses *root, *tmp;
+	const struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	struct cifs_ses *ses = ctx->dfs_root_ses;
+	struct cifs_ses *cur;
+
+	if (!ses)
+		return;
 
-	list_for_each_entry_safe(root, tmp, head, list) {
-		list_del_init(&root->list);
-		cifs_put_smb_ses(root->ses);
-		kfree(root);
+	for (cur = ses; cur; cur = cur->dfs_root_ses) {
+		if (cur->dfs_root_ses)
+			cifs_put_smb_ses(cur->dfs_root_ses);
 	}
+	cifs_put_smb_ses(ses);
 }
 
 #endif /* _CIFS_DFS_H */
diff --git a/fs/smb/client/dfs_cache.c b/fs/smb/client/dfs_cache.c
index 508d831fabe37..0552a864ff08f 100644
--- a/fs/smb/client/dfs_cache.c
+++ b/fs/smb/client/dfs_cache.c
@@ -1278,21 +1278,12 @@ int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb)
 void dfs_cache_refresh(struct work_struct *work)
 {
 	struct TCP_Server_Info *server;
-	struct dfs_root_ses *rses;
 	struct cifs_tcon *tcon;
 	struct cifs_ses *ses;
 
 	tcon = container_of(work, struct cifs_tcon, dfs_cache_work.work);
-	ses = tcon->ses;
-	server = ses->server;
 
-	mutex_lock(&server->refpath_lock);
-	if (server->leaf_fullpath)
-		__refresh_tcon(server->leaf_fullpath + 1, ses, false);
-	mutex_unlock(&server->refpath_lock);
-
-	list_for_each_entry(rses, &tcon->dfs_ses_list, list) {
-		ses = rses->ses;
+	for (ses = tcon->ses; ses; ses = ses->dfs_root_ses) {
 		server = ses->server;
 		mutex_lock(&server->refpath_lock);
 		if (server->leaf_fullpath)
diff --git a/fs/smb/client/misc.c b/fs/smb/client/misc.c
index c3771fc81328f..1ea22b3955a2f 100644
--- a/fs/smb/client/misc.c
+++ b/fs/smb/client/misc.c
@@ -138,9 +138,6 @@ tcon_info_alloc(bool dir_leases_enabled)
 	atomic_set(&ret_buf->num_local_opens, 0);
 	atomic_set(&ret_buf->num_remote_opens, 0);
 	ret_buf->stats_from_time = ktime_get_real_seconds();
-#ifdef CONFIG_CIFS_DFS_UPCALL
-	INIT_LIST_HEAD(&ret_buf->dfs_ses_list);
-#endif
 
 	return ret_buf;
 }
@@ -156,9 +153,6 @@ tconInfoFree(struct cifs_tcon *tcon)
 	atomic_dec(&tconInfoAllocCount);
 	kfree(tcon->nativeFileSystem);
 	kfree_sensitive(tcon->password);
-#ifdef CONFIG_CIFS_DFS_UPCALL
-	dfs_put_root_smb_sessions(&tcon->dfs_ses_list);
-#endif
 	kfree(tcon->origin_fullpath);
 	kfree(tcon);
 }
-- 
cgit 1.2.3-korg


From 0a05ad21d77a188d06481c36d6016805a881bcc0 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Mon, 1 Apr 2024 22:44:07 -0300
Subject: smb: client: refresh referral without acquiring refpath_lock

Avoid refreshing DFS referral with refpath_lock acquired as the I/O
could block for a while due to a potentially disconnected or slow DFS
root server and then making other threads - that use same @server and
don't require a DFS root server - unable to make any progress.

Cc: stable@vger.kernel.org # 6.4+
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/dfs_cache.c | 44 ++++++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 20 deletions(-)

(limited to 'fs')

diff --git a/fs/smb/client/dfs_cache.c b/fs/smb/client/dfs_cache.c
index 0552a864ff08f..11c8efecf7aa1 100644
--- a/fs/smb/client/dfs_cache.c
+++ b/fs/smb/client/dfs_cache.c
@@ -1172,8 +1172,8 @@ static bool is_ses_good(struct cifs_ses *ses)
 	return ret;
 }
 
-/* Refresh dfs referral of tcon and mark it for reconnect if needed */
-static int __refresh_tcon(const char *path, struct cifs_ses *ses, bool force_refresh)
+/* Refresh dfs referral of @ses and mark it for reconnect if needed */
+static void __refresh_ses_referral(struct cifs_ses *ses, bool force_refresh)
 {
 	struct TCP_Server_Info *server = ses->server;
 	DFS_CACHE_TGT_LIST(old_tl);
@@ -1181,10 +1181,21 @@ static int __refresh_tcon(const char *path, struct cifs_ses *ses, bool force_ref
 	bool needs_refresh = false;
 	struct cache_entry *ce;
 	unsigned int xid;
+	char *path = NULL;
 	int rc = 0;
 
 	xid = get_xid();
 
+	mutex_lock(&server->refpath_lock);
+	if (server->leaf_fullpath) {
+		path = kstrdup(server->leaf_fullpath + 1, GFP_ATOMIC);
+		if (!path)
+			rc = -ENOMEM;
+	}
+	mutex_unlock(&server->refpath_lock);
+	if (!path)
+		goto out;
+
 	down_read(&htable_rw_lock);
 	ce = lookup_cache_entry(path);
 	needs_refresh = force_refresh || IS_ERR(ce) || cache_entry_expired(ce);
@@ -1218,19 +1229,17 @@ out:
 	free_xid(xid);
 	dfs_cache_free_tgts(&old_tl);
 	dfs_cache_free_tgts(&new_tl);
-	return rc;
+	kfree(path);
 }
 
-static int refresh_tcon(struct cifs_tcon *tcon, bool force_refresh)
+static inline void refresh_ses_referral(struct cifs_ses *ses)
 {
-	struct TCP_Server_Info *server = tcon->ses->server;
-	struct cifs_ses *ses = tcon->ses;
+	__refresh_ses_referral(ses, false);
+}
 
-	mutex_lock(&server->refpath_lock);
-	if (server->leaf_fullpath)
-		__refresh_tcon(server->leaf_fullpath + 1, ses, force_refresh);
-	mutex_unlock(&server->refpath_lock);
-	return 0;
+static inline void force_refresh_ses_referral(struct cifs_ses *ses)
+{
+	__refresh_ses_referral(ses, true);
 }
 
 /**
@@ -1271,25 +1280,20 @@ int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb)
 	 */
 	cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
 
-	return refresh_tcon(tcon, true);
+	force_refresh_ses_referral(tcon->ses);
+	return 0;
 }
 
 /* Refresh all DFS referrals related to DFS tcon */
 void dfs_cache_refresh(struct work_struct *work)
 {
-	struct TCP_Server_Info *server;
 	struct cifs_tcon *tcon;
 	struct cifs_ses *ses;
 
 	tcon = container_of(work, struct cifs_tcon, dfs_cache_work.work);
 
-	for (ses = tcon->ses; ses; ses = ses->dfs_root_ses) {
-		server = ses->server;
-		mutex_lock(&server->refpath_lock);
-		if (server->leaf_fullpath)
-			__refresh_tcon(server->leaf_fullpath + 1, ses, false);
-		mutex_unlock(&server->refpath_lock);
-	}
+	for (ses = tcon->ses; ses; ses = ses->dfs_root_ses)
+		refresh_ses_referral(ses);
 
 	queue_delayed_work(dfscache_wq, &tcon->dfs_cache_work,
 			   atomic_read(&dfs_cache_ttl) * HZ);
-- 
cgit 1.2.3-korg


From 4a5ba0e0bfe552ac7451f57e304f6343c3d87f89 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Mon, 1 Apr 2024 22:44:08 -0300
Subject: smb: client: handle DFS tcons in cifs_construct_tcon()

The tcons created by cifs_construct_tcon() on multiuser mounts must
also be able to failover and refresh DFS referrals, so set the
appropriate fields in order to get a full DFS tcon.  They could be
shared among different superblocks later, too.

Cc: stable@vger.kernel.org # 6.4+
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404021518.3Xu2VU4s-lkp@intel.com/
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/connect.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'fs')

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index 38b75cfa06e3e..9a35788814961 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -3995,6 +3995,7 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon = NULL;
 	struct smb3_fs_context *ctx;
+	char *origin_fullpath = NULL;
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (ctx == NULL)
@@ -4018,6 +4019,7 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
 	ctx->sign = master_tcon->ses->sign;
 	ctx->seal = master_tcon->seal;
 	ctx->witness = master_tcon->use_witness;
+	ctx->dfs_root_ses = master_tcon->ses->dfs_root_ses;
 
 	rc = cifs_set_vol_auth(ctx, master_tcon->ses);
 	if (rc) {
@@ -4037,12 +4039,39 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
 		goto out;
 	}
 
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	spin_lock(&master_tcon->tc_lock);
+	if (master_tcon->origin_fullpath) {
+		spin_unlock(&master_tcon->tc_lock);
+		origin_fullpath = dfs_get_path(cifs_sb, cifs_sb->ctx->source);
+		if (IS_ERR(origin_fullpath)) {
+			tcon = ERR_CAST(origin_fullpath);
+			origin_fullpath = NULL;
+			cifs_put_smb_ses(ses);
+			goto out;
+		}
+	} else {
+		spin_unlock(&master_tcon->tc_lock);
+	}
+#endif
+
 	tcon = cifs_get_tcon(ses, ctx);
 	if (IS_ERR(tcon)) {
 		cifs_put_smb_ses(ses);
 		goto out;
 	}
 
+#ifdef CONFIG_CIFS_DFS_UPCALL
+	if (origin_fullpath) {
+		spin_lock(&tcon->tc_lock);
+		tcon->origin_fullpath = origin_fullpath;
+		spin_unlock(&tcon->tc_lock);
+		origin_fullpath = NULL;
+		queue_delayed_work(dfscache_wq, &tcon->dfs_cache_work,
+				   dfs_cache_get_ttl() * HZ);
+	}
+#endif
+
 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
 	if (cap_unix(ses))
 		reset_cifs_unix_caps(0, tcon, NULL, ctx);
@@ -4051,6 +4080,7 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
 out:
 	kfree(ctx->username);
 	kfree_sensitive(ctx->password);
+	kfree(origin_fullpath);
 	kfree(ctx);
 
 	return tcon;
-- 
cgit 1.2.3-korg


From 93cee45ccfebc62a3bb4cd622b89e00c8c7d8493 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Mon, 1 Apr 2024 22:44:09 -0300
Subject: smb: client: serialise cifs_construct_tcon() with cifs_mount_mutex

Serialise cifs_construct_tcon() with cifs_mount_mutex to handle
parallel mounts that may end up reusing the session and tcon created
by it.

Cc: stable@vger.kernel.org # 6.4+
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/connect.c    | 13 ++++++++++++-
 fs/smb/client/fs_context.c |  6 +++---
 fs/smb/client/fs_context.h | 12 ++++++++++++
 3 files changed, 27 insertions(+), 4 deletions(-)

(limited to 'fs')

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index 9a35788814961..95e4bda4fd517 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -3988,7 +3988,7 @@ cifs_set_vol_auth(struct smb3_fs_context *ctx, struct cifs_ses *ses)
 }
 
 static struct cifs_tcon *
-cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
+__cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
 {
 	int rc;
 	struct cifs_tcon *master_tcon = cifs_sb_master_tcon(cifs_sb);
@@ -4086,6 +4086,17 @@ out:
 	return tcon;
 }
 
+static struct cifs_tcon *
+cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
+{
+	struct cifs_tcon *ret;
+
+	cifs_mount_lock();
+	ret = __cifs_construct_tcon(cifs_sb, fsuid);
+	cifs_mount_unlock();
+	return ret;
+}
+
 struct cifs_tcon *
 cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
 {
diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c
index bdcbe6ff2739a..b7bfe705b2c49 100644
--- a/fs/smb/client/fs_context.c
+++ b/fs/smb/client/fs_context.c
@@ -37,7 +37,7 @@
 #include "rfc1002pdu.h"
 #include "fs_context.h"
 
-static DEFINE_MUTEX(cifs_mount_mutex);
+DEFINE_MUTEX(cifs_mount_mutex);
 
 static const match_table_t cifs_smb_version_tokens = {
 	{ Smb_1, SMB1_VERSION_STRING },
@@ -783,9 +783,9 @@ static int smb3_get_tree(struct fs_context *fc)
 
 	if (err)
 		return err;
-	mutex_lock(&cifs_mount_mutex);
+	cifs_mount_lock();
 	ret = smb3_get_tree_common(fc);
-	mutex_unlock(&cifs_mount_mutex);
+	cifs_mount_unlock();
 	return ret;
 }
 
diff --git a/fs/smb/client/fs_context.h b/fs/smb/client/fs_context.h
index 7863f2248c4df..8a35645e0b65b 100644
--- a/fs/smb/client/fs_context.h
+++ b/fs/smb/client/fs_context.h
@@ -304,4 +304,16 @@ extern void smb3_update_mnt_flags(struct cifs_sb_info *cifs_sb);
 #define MAX_CACHED_FIDS 16
 extern char *cifs_sanitize_prepath(char *prepath, gfp_t gfp);
 
+extern struct mutex cifs_mount_mutex;
+
+static inline void cifs_mount_lock(void)
+{
+	mutex_lock(&cifs_mount_mutex);
+}
+
+static inline void cifs_mount_unlock(void)
+{
+	mutex_unlock(&cifs_mount_mutex);
+}
+
 #endif
-- 
cgit 1.2.3-korg


From 173217bd73365867378b5e75a86f0049e1069ee8 Mon Sep 17 00:00:00 2001
From: Ritvik Budhiraja <rbudhiraja@microsoft.com>
Date: Tue, 2 Apr 2024 14:01:28 -0500
Subject: smb3: retrying on failed server close

In the current implementation, CIFS close sends a close to the
server and does not check for the success of the server close.
This patch adds functionality to check for server close return
status and retries in case of an EBUSY or EAGAIN error.

This can help avoid handle leaks

Cc: stable@vger.kernel.org
Signed-off-by: Ritvik Budhiraja <rbudhiraja@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/cached_dir.c |  6 +++--
 fs/smb/client/cifsfs.c     | 11 ++++++++
 fs/smb/client/cifsglob.h   |  7 ++++--
 fs/smb/client/file.c       | 63 +++++++++++++++++++++++++++++++++++++++++-----
 fs/smb/client/smb1ops.c    |  4 +--
 fs/smb/client/smb2ops.c    |  9 ++++---
 fs/smb/client/smb2pdu.c    |  2 +-
 7 files changed, 85 insertions(+), 17 deletions(-)

(limited to 'fs')

diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index a0017724d5239..13a9d7acf8f8e 100644
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -417,6 +417,7 @@ smb2_close_cached_fid(struct kref *ref)
 {
 	struct cached_fid *cfid = container_of(ref, struct cached_fid,
 					       refcount);
+	int rc;
 
 	spin_lock(&cfid->cfids->cfid_list_lock);
 	if (cfid->on_list) {
@@ -430,9 +431,10 @@ smb2_close_cached_fid(struct kref *ref)
 	cfid->dentry = NULL;
 
 	if (cfid->is_open) {
-		SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
+		rc = SMB2_close(0, cfid->tcon, cfid->fid.persistent_fid,
 			   cfid->fid.volatile_fid);
-		atomic_dec(&cfid->tcon->num_remote_opens);
+		if (rc != -EBUSY && rc != -EAGAIN)
+			atomic_dec(&cfid->tcon->num_remote_opens);
 	}
 
 	free_cached_dir(cfid);
diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index aa6f1ecb7c0e8..d41eedbff674a 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -156,6 +156,7 @@ struct workqueue_struct	*decrypt_wq;
 struct workqueue_struct	*fileinfo_put_wq;
 struct workqueue_struct	*cifsoplockd_wq;
 struct workqueue_struct	*deferredclose_wq;
+struct workqueue_struct	*serverclose_wq;
 __u32 cifs_lock_secret;
 
 /*
@@ -1888,6 +1889,13 @@ init_cifs(void)
 		goto out_destroy_cifsoplockd_wq;
 	}
 
+	serverclose_wq = alloc_workqueue("serverclose",
+					   WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
+	if (!serverclose_wq) {
+		rc = -ENOMEM;
+		goto out_destroy_serverclose_wq;
+	}
+
 	rc = cifs_init_inodecache();
 	if (rc)
 		goto out_destroy_deferredclose_wq;
@@ -1962,6 +1970,8 @@ out_destroy_decrypt_wq:
 	destroy_workqueue(decrypt_wq);
 out_destroy_cifsiod_wq:
 	destroy_workqueue(cifsiod_wq);
+out_destroy_serverclose_wq:
+	destroy_workqueue(serverclose_wq);
 out_clean_proc:
 	cifs_proc_clean();
 	return rc;
@@ -1991,6 +2001,7 @@ exit_cifs(void)
 	destroy_workqueue(cifsoplockd_wq);
 	destroy_workqueue(decrypt_wq);
 	destroy_workqueue(fileinfo_put_wq);
+	destroy_workqueue(serverclose_wq);
 	destroy_workqueue(cifsiod_wq);
 	cifs_proc_clean();
 }
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 286afbe346be0..77ca7861a2cc8 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -442,10 +442,10 @@ struct smb_version_operations {
 	/* set fid protocol-specific info */
 	void (*set_fid)(struct cifsFileInfo *, struct cifs_fid *, __u32);
 	/* close a file */
-	void (*close)(const unsigned int, struct cifs_tcon *,
+	int (*close)(const unsigned int, struct cifs_tcon *,
 		      struct cifs_fid *);
 	/* close a file, returning file attributes and timestamps */
-	void (*close_getattr)(const unsigned int xid, struct cifs_tcon *tcon,
+	int (*close_getattr)(const unsigned int xid, struct cifs_tcon *tcon,
 		      struct cifsFileInfo *pfile_info);
 	/* send a flush request to the server */
 	int (*flush)(const unsigned int, struct cifs_tcon *, struct cifs_fid *);
@@ -1439,6 +1439,7 @@ struct cifsFileInfo {
 	bool swapfile:1;
 	bool oplock_break_cancelled:1;
 	bool status_file_deleted:1; /* file has been deleted */
+	bool offload:1; /* offload final part of _put to a wq */
 	unsigned int oplock_epoch; /* epoch from the lease break */
 	__u32 oplock_level; /* oplock/lease level from the lease break */
 	int count;
@@ -1447,6 +1448,7 @@ struct cifsFileInfo {
 	struct cifs_search_info srch_inf;
 	struct work_struct oplock_break; /* work for oplock breaks */
 	struct work_struct put; /* work for the final part of _put */
+	struct work_struct serverclose; /* work for serverclose */
 	struct delayed_work deferred;
 	bool deferred_close_scheduled; /* Flag to indicate close is scheduled */
 	char *symlink_target;
@@ -2103,6 +2105,7 @@ extern struct workqueue_struct *decrypt_wq;
 extern struct workqueue_struct *fileinfo_put_wq;
 extern struct workqueue_struct *cifsoplockd_wq;
 extern struct workqueue_struct *deferredclose_wq;
+extern struct workqueue_struct *serverclose_wq;
 extern __u32 cifs_lock_secret;
 
 extern mempool_t *cifs_sm_req_poolp;
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index ab536ce8a04a5..9be37d0fe724e 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -459,6 +459,7 @@ cifs_down_write(struct rw_semaphore *sem)
 }
 
 static void cifsFileInfo_put_work(struct work_struct *work);
+void serverclose_work(struct work_struct *work);
 
 struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
 				       struct tcon_link *tlink, __u32 oplock,
@@ -505,6 +506,7 @@ struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
 	cfile->tlink = cifs_get_tlink(tlink);
 	INIT_WORK(&cfile->oplock_break, cifs_oplock_break);
 	INIT_WORK(&cfile->put, cifsFileInfo_put_work);
+	INIT_WORK(&cfile->serverclose, serverclose_work);
 	INIT_DELAYED_WORK(&cfile->deferred, smb2_deferred_work_close);
 	mutex_init(&cfile->fh_mutex);
 	spin_lock_init(&cfile->file_info_lock);
@@ -596,6 +598,40 @@ static void cifsFileInfo_put_work(struct work_struct *work)
 	cifsFileInfo_put_final(cifs_file);
 }
 
+void serverclose_work(struct work_struct *work)
+{
+	struct cifsFileInfo *cifs_file = container_of(work,
+			struct cifsFileInfo, serverclose);
+
+	struct cifs_tcon *tcon = tlink_tcon(cifs_file->tlink);
+
+	struct TCP_Server_Info *server = tcon->ses->server;
+	int rc = 0;
+	int retries = 0;
+	int MAX_RETRIES = 4;
+
+	do {
+		if (server->ops->close_getattr)
+			rc = server->ops->close_getattr(0, tcon, cifs_file);
+		else if (server->ops->close)
+			rc = server->ops->close(0, tcon, &cifs_file->fid);
+
+		if (rc == -EBUSY || rc == -EAGAIN) {
+			retries++;
+			msleep(250);
+		}
+	} while ((rc == -EBUSY || rc == -EAGAIN) && (retries < MAX_RETRIES)
+	);
+
+	if (retries == MAX_RETRIES)
+		pr_warn("Serverclose failed %d times, giving up\n", MAX_RETRIES);
+
+	if (cifs_file->offload)
+		queue_work(fileinfo_put_wq, &cifs_file->put);
+	else
+		cifsFileInfo_put_final(cifs_file);
+}
+
 /**
  * cifsFileInfo_put - release a reference of file priv data
  *
@@ -636,10 +672,13 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file,
 	struct cifs_fid fid = {};
 	struct cifs_pending_open open;
 	bool oplock_break_cancelled;
+	bool serverclose_offloaded = false;
 
 	spin_lock(&tcon->open_file_lock);
 	spin_lock(&cifsi->open_file_lock);
 	spin_lock(&cifs_file->file_info_lock);
+
+	cifs_file->offload = offload;
 	if (--cifs_file->count > 0) {
 		spin_unlock(&cifs_file->file_info_lock);
 		spin_unlock(&cifsi->open_file_lock);
@@ -681,13 +720,20 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file,
 	if (!tcon->need_reconnect && !cifs_file->invalidHandle) {
 		struct TCP_Server_Info *server = tcon->ses->server;
 		unsigned int xid;
+		int rc = 0;
 
 		xid = get_xid();
 		if (server->ops->close_getattr)
-			server->ops->close_getattr(xid, tcon, cifs_file);
+			rc = server->ops->close_getattr(xid, tcon, cifs_file);
 		else if (server->ops->close)
-			server->ops->close(xid, tcon, &cifs_file->fid);
+			rc = server->ops->close(xid, tcon, &cifs_file->fid);
 		_free_xid(xid);
+
+		if (rc == -EBUSY || rc == -EAGAIN) {
+			// Server close failed, hence offloading it as an async op
+			queue_work(serverclose_wq, &cifs_file->serverclose);
+			serverclose_offloaded = true;
+		}
 	}
 
 	if (oplock_break_cancelled)
@@ -695,10 +741,15 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file,
 
 	cifs_del_pending_open(&open);
 
-	if (offload)
-		queue_work(fileinfo_put_wq, &cifs_file->put);
-	else
-		cifsFileInfo_put_final(cifs_file);
+	// if serverclose has been offloaded to wq (on failure), it will
+	// handle offloading put as well. If serverclose not offloaded,
+	// we need to handle offloading put here.
+	if (!serverclose_offloaded) {
+		if (offload)
+			queue_work(fileinfo_put_wq, &cifs_file->put);
+		else
+			cifsFileInfo_put_final(cifs_file);
+	}
 }
 
 int cifs_open(struct inode *inode, struct file *file)
diff --git a/fs/smb/client/smb1ops.c b/fs/smb/client/smb1ops.c
index a9eaba8083b0d..212ec6f66ec65 100644
--- a/fs/smb/client/smb1ops.c
+++ b/fs/smb/client/smb1ops.c
@@ -753,11 +753,11 @@ cifs_set_fid(struct cifsFileInfo *cfile, struct cifs_fid *fid, __u32 oplock)
 	cinode->can_cache_brlcks = CIFS_CACHE_WRITE(cinode);
 }
 
-static void
+static int
 cifs_close_file(const unsigned int xid, struct cifs_tcon *tcon,
 		struct cifs_fid *fid)
 {
-	CIFSSMBClose(xid, tcon, fid->netfid);
+	return CIFSSMBClose(xid, tcon, fid->netfid);
 }
 
 static int
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 35bf7eb315cdf..87b63f6ad2e2e 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -1412,14 +1412,14 @@ smb2_set_fid(struct cifsFileInfo *cfile, struct cifs_fid *fid, __u32 oplock)
 	memcpy(cfile->fid.create_guid, fid->create_guid, 16);
 }
 
-static void
+static int
 smb2_close_file(const unsigned int xid, struct cifs_tcon *tcon,
 		struct cifs_fid *fid)
 {
-	SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
+	return SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
 }
 
-static void
+static int
 smb2_close_getattr(const unsigned int xid, struct cifs_tcon *tcon,
 		   struct cifsFileInfo *cfile)
 {
@@ -1430,7 +1430,7 @@ smb2_close_getattr(const unsigned int xid, struct cifs_tcon *tcon,
 	rc = __SMB2_close(xid, tcon, cfile->fid.persistent_fid,
 		   cfile->fid.volatile_fid, &file_inf);
 	if (rc)
-		return;
+		return rc;
 
 	inode = d_inode(cfile->dentry);
 
@@ -1459,6 +1459,7 @@ smb2_close_getattr(const unsigned int xid, struct cifs_tcon *tcon,
 
 	/* End of file and Attributes should not have to be updated on close */
 	spin_unlock(&inode->i_lock);
+	return rc;
 }
 
 static int
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 3ea688558e6c9..c0c4933af5fc3 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -3628,9 +3628,9 @@ replay_again:
 			memcpy(&pbuf->network_open_info,
 			       &rsp->network_open_info,
 			       sizeof(pbuf->network_open_info));
+		atomic_dec(&tcon->num_remote_opens);
 	}
 
-	atomic_dec(&tcon->num_remote_opens);
 close_exit:
 	SMB2_close_free(&rqst);
 	free_rsp_buf(resp_buftype, rsp);
-- 
cgit 1.2.3-korg


From ca545b7f0823f19db0f1148d59bc5e1a56634502 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Tue, 2 Apr 2024 16:33:53 -0300
Subject: smb: client: fix potential UAF in cifs_debug_files_proc_show()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/cifs_debug.c |  2 ++
 fs/smb/client/cifsglob.h   | 10 ++++++++++
 2 files changed, 12 insertions(+)

(limited to 'fs')

diff --git a/fs/smb/client/cifs_debug.c b/fs/smb/client/cifs_debug.c
index 226d4835c92db..c9aec9a38ad36 100644
--- a/fs/smb/client/cifs_debug.c
+++ b/fs/smb/client/cifs_debug.c
@@ -250,6 +250,8 @@ static int cifs_debug_files_proc_show(struct seq_file *m, void *v)
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
 		list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+			if (cifs_ses_exiting(ses))
+				continue;
 			list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 				spin_lock(&tcon->open_file_lock);
 				list_for_each_entry(cfile, &tcon->openFileList, tlist) {
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 77ca7861a2cc8..f6a302205f89c 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -2325,4 +2325,14 @@ struct smb2_compound_vars {
 	struct kvec ea_iov;
 };
 
+static inline bool cifs_ses_exiting(struct cifs_ses *ses)
+{
+	bool ret;
+
+	spin_lock(&ses->ses_lock);
+	ret = ses->ses_status == SES_EXITING;
+	spin_unlock(&ses->ses_lock);
+	return ret;
+}
+
 #endif	/* _CIFS_GLOB_H */
-- 
cgit 1.2.3-korg


From 58acd1f497162e7d282077f816faa519487be045 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Tue, 2 Apr 2024 16:33:54 -0300
Subject: smb: client: fix potential UAF in cifs_dump_full_key()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/ioctl.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'fs')

diff --git a/fs/smb/client/ioctl.c b/fs/smb/client/ioctl.c
index c012dfdba80d4..855ac5a62edfa 100644
--- a/fs/smb/client/ioctl.c
+++ b/fs/smb/client/ioctl.c
@@ -247,7 +247,9 @@ static int cifs_dump_full_key(struct cifs_tcon *tcon, struct smb3_full_key_debug
 		spin_lock(&cifs_tcp_ses_lock);
 		list_for_each_entry(server_it, &cifs_tcp_ses_list, tcp_ses_list) {
 			list_for_each_entry(ses_it, &server_it->smb_ses_list, smb_ses_list) {
-				if (ses_it->Suid == out.session_id) {
+				spin_lock(&ses_it->ses_lock);
+				if (ses_it->ses_status != SES_EXITING &&
+				    ses_it->Suid == out.session_id) {
 					ses = ses_it;
 					/*
 					 * since we are using the session outside the crit
@@ -255,9 +257,11 @@ static int cifs_dump_full_key(struct cifs_tcon *tcon, struct smb3_full_key_debug
 					 * so increment its refcount
 					 */
 					cifs_smb_ses_inc_refcount(ses);
+					spin_unlock(&ses_it->ses_lock);
 					found = true;
 					goto search_end;
 				}
+				spin_unlock(&ses_it->ses_lock);
 			}
 		}
 search_end:
-- 
cgit 1.2.3-korg


From d3da25c5ac84430f89875ca7485a3828150a7e0a Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Tue, 2 Apr 2024 16:33:55 -0300
Subject: smb: client: fix potential UAF in cifs_stats_proc_write()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/cifs_debug.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'fs')

diff --git a/fs/smb/client/cifs_debug.c b/fs/smb/client/cifs_debug.c
index c9aec9a38ad36..8535c99074626 100644
--- a/fs/smb/client/cifs_debug.c
+++ b/fs/smb/client/cifs_debug.c
@@ -678,6 +678,8 @@ static ssize_t cifs_stats_proc_write(struct file *file,
 			}
 #endif /* CONFIG_CIFS_STATS2 */
 			list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+				if (cifs_ses_exiting(ses))
+					continue;
 				list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 					atomic_set(&tcon->num_smbs_sent, 0);
 					spin_lock(&tcon->stat_lock);
-- 
cgit 1.2.3-korg


From 0865ffefea197b437ba78b5dd8d8e256253efd65 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Tue, 2 Apr 2024 16:33:56 -0300
Subject: smb: client: fix potential UAF in cifs_stats_proc_show()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/cifs_debug.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'fs')

diff --git a/fs/smb/client/cifs_debug.c b/fs/smb/client/cifs_debug.c
index 8535c99074626..c71ae5c043060 100644
--- a/fs/smb/client/cifs_debug.c
+++ b/fs/smb/client/cifs_debug.c
@@ -759,6 +759,8 @@ static int cifs_stats_proc_show(struct seq_file *m, void *v)
 			}
 #endif /* STATS2 */
 		list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+			if (cifs_ses_exiting(ses))
+				continue;
 			list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 				i++;
 				seq_printf(m, "\n%d) %s", i, tcon->tree_name);
-- 
cgit 1.2.3-korg


From 705c76fbf726c7a2f6ff9143d4013b18daaaebf1 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Tue, 2 Apr 2024 16:33:58 -0300
Subject: smb: client: fix potential UAF in smb2_is_valid_lease_break()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/smb2misc.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'fs')

diff --git a/fs/smb/client/smb2misc.c b/fs/smb/client/smb2misc.c
index 82b84a4941dd2..ed6d033dce96d 100644
--- a/fs/smb/client/smb2misc.c
+++ b/fs/smb/client/smb2misc.c
@@ -622,6 +622,8 @@ smb2_is_valid_lease_break(char *buffer, struct TCP_Server_Info *server)
 	/* look up tcon based on tid & uid */
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+		if (cifs_ses_exiting(ses))
+			continue;
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 			spin_lock(&tcon->open_file_lock);
 			cifs_stats_inc(
-- 
cgit 1.2.3-korg


From 22863485a4626ec6ecf297f4cc0aef709bc862e4 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Tue, 2 Apr 2024 16:33:59 -0300
Subject: smb: client: fix potential UAF in smb2_is_valid_oplock_break()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/smb2misc.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'fs')

diff --git a/fs/smb/client/smb2misc.c b/fs/smb/client/smb2misc.c
index ed6d033dce96d..cc72be5a93a93 100644
--- a/fs/smb/client/smb2misc.c
+++ b/fs/smb/client/smb2misc.c
@@ -699,6 +699,8 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
 	/* look up tcon based on tid & uid */
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+		if (cifs_ses_exiting(ses))
+			continue;
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 
 			spin_lock(&tcon->open_file_lock);
-- 
cgit 1.2.3-korg


From 69ccf040acddf33a3a85ec0f6b45ef84b0f7ec29 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Tue, 2 Apr 2024 16:34:00 -0300
Subject: smb: client: fix potential UAF in is_valid_oplock_break()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/misc.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'fs')

diff --git a/fs/smb/client/misc.c b/fs/smb/client/misc.c
index 1ea22b3955a2f..33ac4f8f5050c 100644
--- a/fs/smb/client/misc.c
+++ b/fs/smb/client/misc.c
@@ -481,6 +481,8 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 	/* look up tcon based on tid & uid */
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+		if (cifs_ses_exiting(ses))
+			continue;
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 			if (tcon->tid != buf->Tid)
 				continue;
-- 
cgit 1.2.3-korg


From 63981561ffd2d4987807df4126f96a11e18b0c1d Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Tue, 2 Apr 2024 16:34:02 -0300
Subject: smb: client: fix potential UAF in smb2_is_network_name_deleted()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/smb2ops.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'fs')

diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 87b63f6ad2e2e..b156eefa75d7c 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -2481,6 +2481,8 @@ smb2_is_network_name_deleted(char *buf, struct TCP_Server_Info *server)
 
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+		if (cifs_ses_exiting(ses))
+			continue;
 		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 			if (tcon->tid == le32_to_cpu(shdr->Id.SyncId.TreeId)) {
 				spin_lock(&tcon->tc_lock);
-- 
cgit 1.2.3-korg


From e0e50401cc3921c9eaf1b0e667db174519ea939f Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@manguebit.com>
Date: Tue, 2 Apr 2024 16:34:04 -0300
Subject: smb: client: fix potential UAF in cifs_signal_cifsd_for_reconnect()

Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/smb/client/connect.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'fs')

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index 95e4bda4fd517..85679ae106fd5 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -175,6 +175,8 @@ cifs_signal_cifsd_for_reconnect(struct TCP_Server_Info *server,
 
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
+		if (cifs_ses_exiting(ses))
+			continue;
 		spin_lock(&ses->chan_lock);
 		for (i = 0; i < ses->chan_count; i++) {
 			if (!ses->chans[i].server)
-- 
cgit 1.2.3-korg