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| author | Lukas Czerner <lczerner@redhat.com> | 2011-01-10 12:04:55 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2011-01-10 12:04:55 -0500 |
| commit | 4f531501e44206862735e81ddf2b70d0dcf6acf6 (patch) | |
| tree | 599648348e58760361dc4903e346a5f3f24175c0 | |
| parent | b72143ab3ed566a12560fa4411a1f02c276dcc39 (diff) | |
| download | linux-4f531501e44206862735e81ddf2b70d0dcf6acf6.tar.gz linux-4f531501e44206862735e81ddf2b70d0dcf6acf6.tar.bz2 linux-4f531501e44206862735e81ddf2b70d0dcf6acf6.zip | |
ext4: fix possible overflow in ext4_trim_fs()
When determining last group through ext4_get_group_no_and_offset() the
result may be wrong in cases when range->start and range-len are too
big, because it may overflow when summing up those two numbers.
Fix that by checking range->len and limit its value to
ext4_blocks_count(). This commit was tested by myself with expected
result.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
| -rw-r--r-- | fs/ext4/mballoc.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 46d5414f59c1..7c603a02633e 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4819,6 +4819,7 @@ ext4_grpblk_t ext4_trim_all_free(struct super_block *sb, struct ext4_buddy *e4b, int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) { struct ext4_buddy e4b; + ext4_fsblk_t blocks_count = ext4_blocks_count(EXT4_SB(sb)->s_es); ext4_group_t first_group, last_group; ext4_group_t group, ngroups = ext4_get_groups_count(sb); ext4_grpblk_t cnt = 0, first_block, last_block; @@ -4830,6 +4831,11 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) minlen = range->minlen >> sb->s_blocksize_bits; trimmed = 0; + if (start >= blocks_count) + return -EINVAL; + if (start + len > blocks_count) + len = blocks_count - start; + if (unlikely(minlen > EXT4_BLOCKS_PER_GROUP(sb))) return -EINVAL; |