diff options
| author | Harshad Shirwadkar <harshadshirwadkar@gmail.com> | 2020-04-20 19:39:59 -0700 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2020-06-03 23:16:49 -0400 |
| commit | c36a71b4e35ab35340facdd6964a00956b9fef0a (patch) | |
| tree | bd5d5792db46bc4e03233af0e696601e56385e14 | |
| parent | 39c0ae163f3b3ae691e7cce226ba1984ef6456b1 (diff) | |
ext4: fix EXT_MAX_EXTENT/INDEX to check for zeroed eh_max
If eh->eh_max is 0, EXT_MAX_EXTENT/INDEX would evaluate to unsigned
(-1) resulting in illegal memory accesses. Although there is no
consistent repro, we see that generic/019 sometimes crashes because of
this bug.
Ran gce-xfstests smoke and verified that there were no regressions.
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20200421023959.20879-2-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
| -rw-r--r-- | fs/ext4/ext4_extents.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h index 1c216fcc202a..44e59881a1f0 100644 --- a/fs/ext4/ext4_extents.h +++ b/fs/ext4/ext4_extents.h @@ -170,10 +170,13 @@ struct partial_cluster { (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) #define EXT_LAST_INDEX(__hdr__) \ (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) -#define EXT_MAX_EXTENT(__hdr__) \ - (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) +#define EXT_MAX_EXTENT(__hdr__) \ + ((le16_to_cpu((__hdr__)->eh_max)) ? \ + ((EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)) \ + : 0) #define EXT_MAX_INDEX(__hdr__) \ - (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) + ((le16_to_cpu((__hdr__)->eh_max)) ? \ + ((EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)) : 0) static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode) { |