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authorLukas Czerner <lczerner@redhat.com>2011-01-10 12:04:55 -0500
committerTheodore Ts'o <tytso@mit.edu>2011-01-10 12:04:55 -0500
commit4f531501e44206862735e81ddf2b70d0dcf6acf6 (patch)
tree599648348e58760361dc4903e346a5f3f24175c0 /fs
parentb72143ab3ed566a12560fa4411a1f02c276dcc39 (diff)
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext4/mballoc.c6
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;