diff options
author | James Morris <jmorris@redhat.com> | 2004-08-23 21:31:13 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-08-23 21:31:13 -0700 |
commit | f22f9adedabc7989fb81f24dc64de3b0715b8fa6 (patch) | |
tree | a2db13fbcec1f20f4317acfd0e15613e891f6f65 /security | |
parent | ef53b198e5a457487b148c5f6e84ae85e7c8df83 (diff) | |
download | history-f22f9adedabc7989fb81f24dc64de3b0715b8fa6.tar.gz |
[PATCH] libfs: move transaction file ops into libfs
Below is an updated version of the patch which moves duplicated
transaction-based file operation code into libfs. Since the last post, the
patch has been through a couple of iterations with Al, who suggested a
number of cleanups including locking and interface simplification.
For filesystem writers, the interface is now much simpler. The
simple_transaction_get() helper should be part of the file op write method.
This safely obtains the transaction request data during write(), allocates
a page for it and stores it there. The data is returned to the caller for
potential further processing, which then makes it available for the next
read() call via simple_transaction_set(). See the selinuxfs and nfsctl
code for examples of use.
Signed-off-by: James Morris <jmorris@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'security')
-rw-r--r-- | security/selinux/selinuxfs.c | 103 |
1 files changed, 16 insertions, 87 deletions
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 975a17708de839..e226a991703cd2 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -390,103 +390,31 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = { [SEL_USER] = sel_write_user, }; -/* an argresp is stored in an allocated page and holds the - * size of the argument or response, along with its content - */ -struct argresp { - ssize_t size; - char data[0]; -}; - -#define PAYLOAD_SIZE (PAGE_SIZE - sizeof(struct argresp)) - -/* - * transaction based IO methods. - * The file expects a single write which triggers the transaction, and then - * possibly a read which collects the result - which is stored in a - * file-local buffer. - */ -static ssize_t TA_write(struct file *file, const char __user *buf, size_t size, loff_t *pos) +static ssize_t selinux_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos) { ino_t ino = file->f_dentry->d_inode->i_ino; - struct argresp *ar; - ssize_t rv = 0; + char *data; + ssize_t rv; if (ino >= sizeof(write_op)/sizeof(write_op[0]) || !write_op[ino]) return -EINVAL; - if (file->private_data) - return -EINVAL; /* only one write allowed per open */ - if (size > PAYLOAD_SIZE - 1) /* allow one byte for null terminator */ - return -EFBIG; - ar = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (!ar) - return -ENOMEM; - memset(ar, 0, PAGE_SIZE); /* clear buffer, particularly last byte */ - ar->size = 0; - down(&file->f_dentry->d_inode->i_sem); - if (file->private_data) - rv = -EINVAL; - else - file->private_data = ar; - up(&file->f_dentry->d_inode->i_sem); - if (rv) { - kfree(ar); - return rv; - } - if (copy_from_user(ar->data, buf, size)) - return -EFAULT; + data = simple_transaction_get(file, buf, size); + if (IS_ERR(data)) + return PTR_ERR(data); - rv = write_op[ino](file, ar->data, size); + rv = write_op[ino](file, data, size); if (rv>0) { - ar->size = rv; + simple_transaction_set(file, rv); rv = size; } return rv; } -static ssize_t TA_read(struct file *file, char __user *buf, size_t size, loff_t *pos) -{ - struct argresp *ar; - ssize_t rv = 0; - - if (file->private_data == NULL) - rv = TA_write(file, buf, 0, pos); - if (rv < 0) - return rv; - - ar = file->private_data; - if (!ar) - return 0; - if (*pos >= ar->size) - return 0; - if (*pos + size > ar->size) - size = ar->size - *pos; - if (copy_to_user(buf, ar->data + *pos, size)) - return -EFAULT; - *pos += size; - return size; -} - -static int TA_open(struct inode *inode, struct file *file) -{ - file->private_data = NULL; - return 0; -} - -static int TA_release(struct inode *inode, struct file *file) -{ - void *p = file->private_data; - file->private_data = NULL; - kfree(p); - return 0; -} - static struct file_operations transaction_ops = { - .write = TA_write, - .read = TA_read, - .open = TA_open, - .release = TA_release, + .write = selinux_transaction_write, + .read = simple_transaction_read, + .release = simple_transaction_release, }; /* @@ -534,7 +462,8 @@ static ssize_t sel_write_access(struct file * file, char *buf, size_t size) if (length < 0) goto out2; - length = scnprintf(buf, PAYLOAD_SIZE, "%x %x %x %x %u", + length = scnprintf(buf, SIMPLE_TRANSACTION_LIMIT, + "%x %x %x %x %u", avd.allowed, avd.decided, avd.auditallow, avd.auditdeny, avd.seqno); @@ -588,7 +517,7 @@ static ssize_t sel_write_create(struct file * file, char *buf, size_t size) if (length < 0) goto out2; - if (len > PAYLOAD_SIZE) { + if (len > SIMPLE_TRANSACTION_LIMIT) { printk(KERN_ERR "%s: context size (%u) exceeds payload " "max\n", __FUNCTION__, len); length = -ERANGE; @@ -649,7 +578,7 @@ static ssize_t sel_write_relabel(struct file * file, char *buf, size_t size) if (length < 0) goto out2; - if (len > PAYLOAD_SIZE) { + if (len > SIMPLE_TRANSACTION_LIMIT) { length = -ERANGE; goto out3; } @@ -709,7 +638,7 @@ static ssize_t sel_write_user(struct file * file, char *buf, size_t size) length = rc; goto out3; } - if ((length + len) >= PAYLOAD_SIZE) { + if ((length + len) >= SIMPLE_TRANSACTION_LIMIT) { kfree(newcon); length = -ERANGE; goto out3; |