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SubjectRe: [PATCH] ext4: fix possible overflow in ext4_trim_fs()
On Thu, 25 Nov 2010, Lukas Czerner wrote:

> 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>
> ---
> fs/ext4/mballoc.c | 4 ++++
> 1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 5b4d4e3..7b05d92 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 +4827,9 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
> minlen = range->minlen >> sb->s_blocksize_bits;
> trimmed = 0;
>
> + if (len > blocks_count)
> + len = blocks_count - start;
> +
> if (unlikely(minlen > EXT4_BLOCKS_PER_GROUP(sb)))
> return -EINVAL;
>
>

Hi Ted,

what is the status of this patch ?

-Lukas


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