From 4f531501e44206862735e81ddf2b70d0dcf6acf6 Mon Sep 17 00:00:00 2001 From: Lukas Czerner Date: Mon, 10 Jan 2011 12:04:55 -0500 Subject: [PATCH] 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 --- fs/ext4/mballoc.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 46d5414..7c603a0 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; -- 2.7.4