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* [PATCH] ext4: Avoid underflow of in ext4_trim_fs()
@ 2012-10-09 12:12 Lukas Czerner
  2012-10-09 13:37 ` Carlos Maiolino
  2012-10-11  8:34 ` [PATCH v2] " Lukas Czerner
  0 siblings, 2 replies; 4+ messages in thread
From: Lukas Czerner @ 2012-10-09 12:12 UTC (permalink / raw)
  To: linux-ext4; +Cc: tytso, Lukas Czerner

Currently if len argument in ext4_trim_fs() is smaller than one block,
the 'end' variable underflow. Avoid that by exiting right away if len
is smaller than one file system block.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
---
 fs/ext4/mballoc.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index f8b27bf..06c8526 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4989,13 +4989,18 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 	int ret = 0;
 
 	start = range->start >> sb->s_blocksize_bits;
-	end = start + (range->len >> sb->s_blocksize_bits) - 1;
 	minlen = EXT4_NUM_B2C(EXT4_SB(sb),
 			      range->minlen >> sb->s_blocksize_bits);
 
 	if (unlikely(minlen > EXT4_CLUSTERS_PER_GROUP(sb)) ||
 	    unlikely(start >= max_blks))
 		return -EINVAL;
+
+	end = range->len >> sb->s_blocksize_bits;
+	if (0 == end)
+		goto out;
+	end += start - 1;
+
 	if (end >= max_blks)
 		end = max_blks - 1;
 	if (end <= first_data_blk)
-- 
1.7.7.6


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH] ext4: Avoid underflow of in ext4_trim_fs()
  2012-10-09 12:12 [PATCH] ext4: Avoid underflow of in ext4_trim_fs() Lukas Czerner
@ 2012-10-09 13:37 ` Carlos Maiolino
  2012-10-11  8:34 ` [PATCH v2] " Lukas Czerner
  1 sibling, 0 replies; 4+ messages in thread
From: Carlos Maiolino @ 2012-10-09 13:37 UTC (permalink / raw)
  To: linux-ext4

On Tue, Oct 09, 2012 at 02:12:42PM +0200, Lukas Czerner wrote:
> Currently if len argument in ext4_trim_fs() is smaller than one block,
> the 'end' variable underflow. Avoid that by exiting right away if len
> is smaller than one file system block.
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> ---
>  fs/ext4/mballoc.c |    7 ++++++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index f8b27bf..06c8526 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -4989,13 +4989,18 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
>  	int ret = 0;
>  
>  	start = range->start >> sb->s_blocksize_bits;
> -	end = start + (range->len >> sb->s_blocksize_bits) - 1;
>  	minlen = EXT4_NUM_B2C(EXT4_SB(sb),
>  			      range->minlen >> sb->s_blocksize_bits);
>  
>  	if (unlikely(minlen > EXT4_CLUSTERS_PER_GROUP(sb)) ||
>  	    unlikely(start >= max_blks))
>  		return -EINVAL;
> +
> +	end = range->len >> sb->s_blocksize_bits;
> +	if (0 == end)
> +		goto out;
> +	end += start - 1;
> +
>  	if (end >= max_blks)
>  		end = max_blks - 1;
>  	if (end <= first_data_blk)
> -- 
> 1.7.7.6
> 
> --
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> 
Looks good,

Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
-- 
--Carlos

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH v2] ext4: Avoid underflow of in ext4_trim_fs()
  2012-10-09 12:12 [PATCH] ext4: Avoid underflow of in ext4_trim_fs() Lukas Czerner
  2012-10-09 13:37 ` Carlos Maiolino
@ 2012-10-11  8:34 ` Lukas Czerner
  2012-10-22  4:37   ` Theodore Ts'o
  1 sibling, 1 reply; 4+ messages in thread
From: Lukas Czerner @ 2012-10-11  8:34 UTC (permalink / raw)
  To: linux-ext4; +Cc: tytso, Lukas Czerner

Currently if len argument in ext4_trim_fs() is smaller than one block,
the 'end' variable underflow. Avoid that by returning EINVAL if len is
smaller than file system block.

Also remove useless unlikely().

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
---
v2: reworked, return EINVAL if len < FSB

 fs/ext4/mballoc.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index f8b27bf..e02ae6c 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4993,8 +4993,9 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 	minlen = EXT4_NUM_B2C(EXT4_SB(sb),
 			      range->minlen >> sb->s_blocksize_bits);
 
-	if (unlikely(minlen > EXT4_CLUSTERS_PER_GROUP(sb)) ||
-	    unlikely(start >= max_blks))
+	if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
+	    start >= max_blks ||
+	    range->len < sb->s_blocksize)
 		return -EINVAL;
 	if (end >= max_blks)
 		end = max_blks - 1;
-- 
1.7.7.6


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH v2] ext4: Avoid underflow of in ext4_trim_fs()
  2012-10-11  8:34 ` [PATCH v2] " Lukas Czerner
@ 2012-10-22  4:37   ` Theodore Ts'o
  0 siblings, 0 replies; 4+ messages in thread
From: Theodore Ts'o @ 2012-10-22  4:37 UTC (permalink / raw)
  To: Lukas Czerner; +Cc: linux-ext4

On Thu, Oct 11, 2012 at 10:34:45AM +0200, Lukas Czerner wrote:
> Currently if len argument in ext4_trim_fs() is smaller than one block,
> the 'end' variable underflow. Avoid that by returning EINVAL if len is
> smaller than file system block.
> 
> Also remove useless unlikely().
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>

Thanks, applied.

						- Ted

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2012-10-22  4:37 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2012-10-09 12:12 [PATCH] ext4: Avoid underflow of in ext4_trim_fs() Lukas Czerner
2012-10-09 13:37 ` Carlos Maiolino
2012-10-11  8:34 ` [PATCH v2] " Lukas Czerner
2012-10-22  4:37   ` Theodore Ts'o

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