diff options
| author | Filipe Manana <fdmanana@suse.com> | 2018-10-13 00:37:25 +0100 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-10-17 17:42:46 +0200 |
| commit | 3527a018c00e5dbada2f9d7ed5576437b6dd5cfb (patch) | |
| tree | 03ba27ac5ed2e2aa7d70c10b8bf9f2a9cfe18867 /fs/btrfs | |
| parent | d9352794dad9f28535439d85a815978878c141ab (diff) | |
Btrfs: fix null pointer dereference on compressed write path error
At inode.c:compress_file_range(), under the "free_pages_out" label, we can
end up dereferencing the "pages" pointer when it has a NULL value. This
case happens when "start" has a value of 0 and we fail to allocate memory
for the "pages" pointer. When that happens we jump to the "cont" label and
then enter the "if (start == 0)" branch where we immediately call the
cow_file_range_inline() function. If that function returns 0 (success
creating an inline extent) or an error (like -ENOMEM for example) we jump
to the "free_pages_out" label and then access "pages[i]" leading to a NULL
pointer dereference, since "nr_pages" has a value greater than zero at
that point.
Fix this by setting "nr_pages" to 0 when we fail to allocate memory for
the "pages" pointer.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201119
Fixes: 771ed689d2cd ("Btrfs: Optimize compressed writeback and reads")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/inode.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index f22f77172c5f..f98ddd886036 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -502,6 +502,7 @@ again: pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); if (!pages) { /* just bail out to the uncompressed code */ + nr_pages = 0; goto cont; } |