From 71f8b55bc30e82d6355e07811213d847981a32e2 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 11 Dec 2023 15:08:57 +0000 Subject: afs: Fix the dynamic root's d_delete to always delete unused dentries Fix the afs dynamic root's d_delete function to always delete unused dentries rather than only deleting them if they're positive. With things as they stand upstream, negative dentries stemming from failed DNS lookups stick around preventing retries. Fixes: 66c7e1d319a5 ("afs: Split the dynroot stuff out and give it its own ops tables") Signed-off-by: David Howells Tested-by: Markus Suvanto cc: Marc Dionne cc: linux-afs@lists.infradead.org --- fs/afs/dynroot.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-) diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c index 1fa8cf23bd3609..34474a0616546b 100644 --- a/fs/afs/dynroot.c +++ b/fs/afs/dynroot.c @@ -252,20 +252,9 @@ static int afs_dynroot_d_revalidate(struct dentry *dentry, unsigned int flags) return 1; } -/* - * Allow the VFS to enquire as to whether a dentry should be unhashed (mustn't - * sleep) - * - called from dput() when d_count is going to 0. - * - return 1 to request dentry be unhashed, 0 otherwise - */ -static int afs_dynroot_d_delete(const struct dentry *dentry) -{ - return d_really_is_positive(dentry); -} - const struct dentry_operations afs_dynroot_dentry_operations = { .d_revalidate = afs_dynroot_d_revalidate, - .d_delete = afs_dynroot_d_delete, + .d_delete = always_delete_dentry, .d_release = afs_d_release, .d_automount = afs_d_automount, }; -- cgit 1.2.3-korg From 74cef6872ceaefb5b6c5c60641371ea28702d358 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 11 Dec 2023 15:15:02 +0000 Subject: afs: Fix dynamic root lookup DNS check In the afs dynamic root directory, the ->lookup() function does a DNS check on the cell being asked for and if the DNS upcall reports an error it will report an error back to userspace (typically ENOENT). However, if a failed DNS upcall returns a new-style result, it will return a valid result, with the status field set appropriately to indicate the type of failure - and in that case, dns_query() doesn't return an error and we let stat() complete with no error - which can cause confusion in userspace as subsequent calls that trigger d_automount then fail with ENOENT. Fix this by checking the status result from a valid dns_query() and returning an error if it indicates a failure. Fixes: bbb4c4323a4d ("dns: Allow the dns resolver to retrieve a server set") Reported-by: Markus Suvanto Closes: https://bugzilla.kernel.org/show_bug.cgi?id=216637 Signed-off-by: David Howells Tested-by: Markus Suvanto cc: Marc Dionne cc: linux-afs@lists.infradead.org --- fs/afs/dynroot.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c index 34474a0616546b..1f656005018ea0 100644 --- a/fs/afs/dynroot.c +++ b/fs/afs/dynroot.c @@ -114,6 +114,7 @@ static int afs_probe_cell_name(struct dentry *dentry) struct afs_net *net = afs_d2net(dentry); const char *name = dentry->d_name.name; size_t len = dentry->d_name.len; + char *result = NULL; int ret; /* Names prefixed with a dot are R/W mounts. */ @@ -131,9 +132,22 @@ static int afs_probe_cell_name(struct dentry *dentry) } ret = dns_query(net->net, "afsdb", name, len, "srv=1", - NULL, NULL, false); - if (ret == -ENODATA || ret == -ENOKEY) + &result, NULL, false); + if (ret == -ENODATA || ret == -ENOKEY || ret == 0) ret = -ENOENT; + if (ret > 0 && ret >= sizeof(struct dns_server_list_v1_header)) { + struct dns_server_list_v1_header *v1 = (void *)result; + + if (v1->hdr.zero == 0 && + v1->hdr.content == DNS_PAYLOAD_IS_SERVER_LIST && + v1->hdr.version == 1 && + (v1->status != DNS_LOOKUP_GOOD && + v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) + return -ENOENT; + + } + + kfree(result); return ret; } -- cgit 1.2.3-korg From 39299bdd2546688d92ed9db4948f6219ca1b9542 Mon Sep 17 00:00:00 2001 From: David Howells Date: Sat, 9 Dec 2023 00:41:55 +0000 Subject: keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry If a key has an expiration time, then when that time passes, the key is left around for a certain amount of time before being collected (5 mins by default) so that EKEYEXPIRED can be returned instead of ENOKEY. This is a problem for DNS keys because we want to redo the DNS lookup immediately at that point. Fix this by allowing key types to be marked such that keys of that type don't have this extra period, but are reclaimed as soon as they expire and turn this on for dns_resolver-type keys. To make this easier to handle, key->expiry is changed to be permanent if TIME64_MAX rather than 0. Furthermore, give such new-style negative DNS results a 1s default expiry if no other expiry time is set rather than allowing it to stick around indefinitely. This shouldn't be zero as ls will follow a failing stat call immediately with a second with AT_SYMLINK_NOFOLLOW added. Fixes: 1a4240f4764a ("DNS: Separate out CIFS DNS Resolver code") Signed-off-by: David Howells Tested-by: Markus Suvanto cc: Wang Lei cc: Jeff Layton cc: Steve French cc: Marc Dionne cc: Jarkko Sakkinen cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: linux-afs@lists.infradead.org cc: linux-cifs@vger.kernel.org cc: linux-nfs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: keyrings@vger.kernel.org cc: netdev@vger.kernel.org --- include/linux/key-type.h | 1 + net/dns_resolver/dns_key.c | 10 +++++++++- security/keys/gc.c | 31 +++++++++++++++++++++---------- security/keys/internal.h | 11 ++++++++++- security/keys/key.c | 15 +++++---------- security/keys/proc.c | 2 +- 6 files changed, 47 insertions(+), 23 deletions(-) diff --git a/include/linux/key-type.h b/include/linux/key-type.h index 7d985a1dfe4af9..5caf3ce823733a 100644 --- a/include/linux/key-type.h +++ b/include/linux/key-type.h @@ -73,6 +73,7 @@ struct key_type { unsigned int flags; #define KEY_TYPE_NET_DOMAIN 0x00000001 /* Keys of this type have a net namespace domain */ +#define KEY_TYPE_INSTANT_REAP 0x00000002 /* Keys of this type don't have a delay after expiring */ /* vet a description */ int (*vet_description)(const char *description); diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c index 01e54b46ae0b97..2a6d363763a2bc 100644 --- a/net/dns_resolver/dns_key.c +++ b/net/dns_resolver/dns_key.c @@ -91,6 +91,7 @@ const struct cred *dns_resolver_cache; static int dns_resolver_preparse(struct key_preparsed_payload *prep) { + const struct dns_server_list_v1_header *v1; const struct dns_payload_header *bin; struct user_key_payload *upayload; unsigned long derrno; @@ -122,6 +123,13 @@ dns_resolver_preparse(struct key_preparsed_payload *prep) return -EINVAL; } + v1 = (const struct dns_server_list_v1_header *)bin; + if ((v1->status != DNS_LOOKUP_GOOD && + v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) { + if (prep->expiry == TIME64_MAX) + prep->expiry = ktime_get_real_seconds() + 1; + } + result_len = datalen; goto store_result; } @@ -314,7 +322,7 @@ static long dns_resolver_read(const struct key *key, struct key_type key_type_dns_resolver = { .name = "dns_resolver", - .flags = KEY_TYPE_NET_DOMAIN, + .flags = KEY_TYPE_NET_DOMAIN | KEY_TYPE_INSTANT_REAP, .preparse = dns_resolver_preparse, .free_preparse = dns_resolver_free_preparse, .instantiate = generic_key_instantiate, diff --git a/security/keys/gc.c b/security/keys/gc.c index 3c90807476eb0e..eaddaceda14eab 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -66,6 +66,19 @@ void key_schedule_gc(time64_t gc_at) } } +/* + * Set the expiration time on a key. + */ +void key_set_expiry(struct key *key, time64_t expiry) +{ + key->expiry = expiry; + if (expiry != TIME64_MAX) { + if (!(key->type->flags & KEY_TYPE_INSTANT_REAP)) + expiry += key_gc_delay; + key_schedule_gc(expiry); + } +} + /* * Schedule a dead links collection run. */ @@ -176,7 +189,6 @@ static void key_garbage_collector(struct work_struct *work) static u8 gc_state; /* Internal persistent state */ #define KEY_GC_REAP_AGAIN 0x01 /* - Need another cycle */ #define KEY_GC_REAPING_LINKS 0x02 /* - We need to reap links */ -#define KEY_GC_SET_TIMER 0x04 /* - We need to restart the timer */ #define KEY_GC_REAPING_DEAD_1 0x10 /* - We need to mark dead keys */ #define KEY_GC_REAPING_DEAD_2 0x20 /* - We need to reap dead key links */ #define KEY_GC_REAPING_DEAD_3 0x40 /* - We need to reap dead keys */ @@ -184,21 +196,17 @@ static void key_garbage_collector(struct work_struct *work) struct rb_node *cursor; struct key *key; - time64_t new_timer, limit; + time64_t new_timer, limit, expiry; kenter("[%lx,%x]", key_gc_flags, gc_state); limit = ktime_get_real_seconds(); - if (limit > key_gc_delay) - limit -= key_gc_delay; - else - limit = key_gc_delay; /* Work out what we're going to be doing in this pass */ gc_state &= KEY_GC_REAPING_DEAD_1 | KEY_GC_REAPING_DEAD_2; gc_state <<= 1; if (test_and_clear_bit(KEY_GC_KEY_EXPIRED, &key_gc_flags)) - gc_state |= KEY_GC_REAPING_LINKS | KEY_GC_SET_TIMER; + gc_state |= KEY_GC_REAPING_LINKS; if (test_and_clear_bit(KEY_GC_REAP_KEYTYPE, &key_gc_flags)) gc_state |= KEY_GC_REAPING_DEAD_1; @@ -233,8 +241,11 @@ continue_scanning: } } - if (gc_state & KEY_GC_SET_TIMER) { - if (key->expiry > limit && key->expiry < new_timer) { + expiry = key->expiry; + if (expiry != TIME64_MAX) { + if (!(key->type->flags & KEY_TYPE_INSTANT_REAP)) + expiry += key_gc_delay; + if (expiry > limit && expiry < new_timer) { kdebug("will expire %x in %lld", key_serial(key), key->expiry - limit); new_timer = key->expiry; @@ -276,7 +287,7 @@ maybe_resched: */ kdebug("pass complete"); - if (gc_state & KEY_GC_SET_TIMER && new_timer != (time64_t)TIME64_MAX) { + if (new_timer != TIME64_MAX) { new_timer += key_gc_delay; key_schedule_gc(new_timer); } diff --git a/security/keys/internal.h b/security/keys/internal.h index 471cf36dedc026..2cffa6dc82557b 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -167,6 +167,7 @@ extern unsigned key_gc_delay; extern void keyring_gc(struct key *keyring, time64_t limit); extern void keyring_restriction_gc(struct key *keyring, struct key_type *dead_type); +void key_set_expiry(struct key *key, time64_t expiry); extern void key_schedule_gc(time64_t gc_at); extern void key_schedule_gc_links(void); extern void key_gc_keytype(struct key_type *ktype); @@ -215,10 +216,18 @@ extern struct key *key_get_instantiation_authkey(key_serial_t target_id); */ static inline bool key_is_dead(const struct key *key, time64_t limit) { + time64_t expiry = key->expiry; + + if (expiry != TIME64_MAX) { + if (!(key->type->flags & KEY_TYPE_INSTANT_REAP)) + expiry += key_gc_delay; + if (expiry <= limit) + return true; + } + return key->flags & ((1 << KEY_FLAG_DEAD) | (1 << KEY_FLAG_INVALIDATED)) || - (key->expiry > 0 && key->expiry <= limit) || key->domain_tag->removed; } diff --git a/security/keys/key.c b/security/keys/key.c index 0260a1902922eb..5b10641debd549 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -294,6 +294,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, key->uid = uid; key->gid = gid; key->perm = perm; + key->expiry = TIME64_MAX; key->restrict_link = restrict_link; key->last_used_at = ktime_get_real_seconds(); @@ -463,10 +464,7 @@ static int __key_instantiate_and_link(struct key *key, if (authkey) key_invalidate(authkey); - if (prep->expiry != TIME64_MAX) { - key->expiry = prep->expiry; - key_schedule_gc(prep->expiry + key_gc_delay); - } + key_set_expiry(key, prep->expiry); } } @@ -606,8 +604,7 @@ int key_reject_and_link(struct key *key, atomic_inc(&key->user->nikeys); mark_key_instantiated(key, -error); notify_key(key, NOTIFY_KEY_INSTANTIATED, -error); - key->expiry = ktime_get_real_seconds() + timeout; - key_schedule_gc(key->expiry + key_gc_delay); + key_set_expiry(key, ktime_get_real_seconds() + timeout); if (test_and_clear_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags)) awaken = 1; @@ -723,16 +720,14 @@ found_kernel_type: void key_set_timeout(struct key *key, unsigned timeout) { - time64_t expiry = 0; + time64_t expiry = TIME64_MAX; /* make the changes with the locks held to prevent races */ down_write(&key->sem); if (timeout > 0) expiry = ktime_get_real_seconds() + timeout; - - key->expiry = expiry; - key_schedule_gc(key->expiry + key_gc_delay); + key_set_expiry(key, expiry); up_write(&key->sem); } diff --git a/security/keys/proc.c b/security/keys/proc.c index d0cde6685627f2..4f4e2c1824f18b 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -198,7 +198,7 @@ static int proc_keys_show(struct seq_file *m, void *v) /* come up with a suitable timeout value */ expiry = READ_ONCE(key->expiry); - if (expiry == 0) { + if (expiry == TIME64_MAX) { memcpy(xbuf, "perm", 5); } else if (now >= expiry) { memcpy(xbuf, "expd", 5); -- cgit 1.2.3-korg