From 425fa41072b7dce3d88f392b335e561a770aa6c3 Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Thu, 3 Mar 2011 22:58:37 +0800 Subject: ext3: Fix an overflow in ext3_trim_fs. In a bs=4096 volume, if we call FITRIM with the following parameter as fstrim_range(start = 102400, len = 134144000, minlen = 10240), with the following code: if (len >= EXT3_BLOCKS_PER_GROUP(sb)) len -= (EXT3_BLOCKS_PER_GROUP(sb) - first_block); else last_block = first_block + len; So if len < EXT3_BLOCKS_PER_GROUP while first_block + len > EXT3_BLOCKS_PER_GROUP, last_block will be set to an overflow value which exceeds EXT3_BLOCKS_PER_GROUP. This patch fixes it and adjusts len and last_block accordingly. Cc: Lukas Czerner Cc: Jan Kara Signed-off-by: Tao Ma Signed-off-by: Jan Kara --- fs/ext3/balloc.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c index db1906b4e39c..153242187fce 100644 --- a/fs/ext3/balloc.c +++ b/fs/ext3/balloc.c @@ -2127,10 +2127,15 @@ int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range) if (free_blocks < minlen) continue; - if (len >= EXT3_BLOCKS_PER_GROUP(sb)) - len -= (EXT3_BLOCKS_PER_GROUP(sb) - first_block); - else + /* + * For all the groups except the last one, last block will + * always be EXT3_BLOCKS_PER_GROUP(sb), so we only need to + * change it for the last group in which case first_block + + * len < EXT3_BLOCKS_PER_GROUP(sb). + */ + if (first_block + len < EXT3_BLOCKS_PER_GROUP(sb)) last_block = first_block + len; + len -= last_block - first_block; ret = ext3_trim_all_free(sb, group, first_block, last_block, minlen); -- cgit v1.2.3