[<prev] [next>] [day] [month] [year] [list]
Message-Id: <1294658906-5993-1-git-send-email-lczerner@redhat.com>
Date: Mon, 10 Jan 2011 12:28:26 +0100
From: Lukas Czerner <lczerner@...hat.com>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, lczerner@...hat.com, sandeen@...hat.com
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 <lczerner@...hat.com>
---
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 5b4d4e3..5f3e8a3 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4819,6 +4819,7 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
ext4_group_t group, ngroups = ext4_get_groups_count(sb);
ext4_grpblk_t cnt = 0, first_block, last_block;
uint64_t start, len, minlen, trimmed;
+ ext4_fsblk_t blocks_count = ext4_blocks_count(EXT4_SB(sb)->s_es);
int ret = 0;
start = range->start >> sb->s_blocksize_bits;
@@ -4826,6 +4827,11 @@ 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;
--
1.7.2.3
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists