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| author |   Theodore Ts'o <tytso@mit.edu> | 2013-03-11 23:39:59 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-03-11 23:39:59 -0400 |
| commit | 90ba983f6889e65a3b506b30dc606aa9d1d46cd2 (patch) | |
| tree | 964ad0ccf415e73a7760b5bfe65506f5d825e1cf /fs/ext4/ialloc.c | |
| parent | jbd2: fix use after free in jbd2_journal_dirty_metadata() (diff) | |
| download | linux-dev-90ba983f6889e65a3b506b30dc606aa9d1d46cd2.tar.xz linux-dev-90ba983f6889e65a3b506b30dc606aa9d1d46cd2.zip | |
ext4: use atomic64_t for the per-flexbg free_clusters count
A user who was using a 8TB+ file system and with a very large flexbg
size (> 65536) could cause the atomic_t used in the struct flex_groups
to overflow. This was detected by PaX security patchset:
http://forums.grsecurity.net/viewtopic.php?f=3&t=3289&p=12551#p12551
This bug was introduced in commit 9f24e4208f7e, so it's been around
since 2.6.30. :-(
Fix this by using an atomic64_t for struct orlav_stats's
free_clusters.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/ialloc.c')
| -rw-r--r-- | fs/ext4/ialloc.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 32fd2b9075dd..6c5bb8d993fe 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -324,8 +324,8 @@ error_return: } struct orlov_stats { + __u64 free_clusters; __u32 free_inodes; - __u32 free_clusters; __u32 used_dirs; }; @@ -342,7 +342,7 @@ static void get_orlov_stats(struct super_block *sb, ext4_group_t g, if (flex_size > 1) { stats->free_inodes = atomic_read(&flex_group[g].free_inodes); - stats->free_clusters = atomic_read(&flex_group[g].free_clusters); + stats->free_clusters = atomic64_read(&flex_group[g].free_clusters); stats->used_dirs = atomic_read(&flex_group[g].used_dirs); return; } |