diff options
| author | Eric Sandeen <sandeen@redhat.com> | 2007-10-07 00:52:10 +0200 |
|---|---|---|
| committer | Adrian Bunk <bunk@kernel.org> | 2007-10-07 00:52:10 +0200 |
| commit | a578b99b87e77138219022179799f62c68018d74 (patch) | |
| tree | 31175c31ec5722be70c8d74932ccc729a9f18fa0 /include | |
| parent | 47d9c7762bd6e2d766cba697952f11fba9d5acf6 (diff) | |
sysfs: store sysfs inode nrs in s_ino to avoid readdir oopses (CVE-2007-3104)
Backport of
ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22-rc1/2.6.22-rc1-mm1/broken-out/gregkh-driver-sysfs-allocate-inode-number-using-ida.patch
For regular files in sysfs, sysfs_readdir wants to traverse
sysfs_dirent->s_dentry->d_inode->i_ino to get to the inode number.
But, the dentry can be reclaimed under memory pressure, and there is
no synchronization with readdir. This patch follows Tejun's scheme of
allocating and storing an inode number in the new s_ino member of a
sysfs_dirent, when dirents are created, and retrieving it from there
for readdir, so that the pointer chain doesn't have to be traversed.
Tejun's upstream patch uses a new-ish "ida" allocator which brings
along some extra complexity; this -stable patch has a brain-dead
incrementing counter which does not guarantee uniqueness, but because
sysfs doesn't hash inodes as iunique expects, uniqueness wasn't
guaranteed today anyway.
Adrian Bunk:
Backported to 2.6.16.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sysfs.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 392da5a6dac..b34fa5b8c32 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -72,6 +72,7 @@ struct sysfs_dirent { void * s_element; int s_type; umode_t s_mode; + ino_t s_ino; struct dentry * s_dentry; struct iattr * s_iattr; }; |