* [PATCH v2] btrfs: Fix divide by zero
@ 2020-10-09 1:09 Daniel Xu
2020-10-14 20:26 ` Daniel Xu
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Daniel Xu @ 2020-10-09 1:09 UTC (permalink / raw)
To: linux-btrfs; +Cc: Daniel Xu, kernel-team, josef, quwenruo.btrfs, Qu Wenruo
If there's no parity and num_stripes < ncopies, an btrfs image can
trigger a divide by zero in calc_stripe_length().
The image (see link) was generated through fuzzing.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=209587
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
---
v1->v2:
* Upload test image to kernel bugzilla
fs/btrfs/tree-checker.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 7b1fee630f97..e03c3807921f 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -760,18 +760,36 @@ int btrfs_check_chunk_valid(struct extent_buffer *leaf,
u64 type;
u64 features;
bool mixed = false;
+ int raid_index;
+ int nparity;
+ int ncopies;
length = btrfs_chunk_length(leaf, chunk);
stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
type = btrfs_chunk_type(leaf, chunk);
+ raid_index = btrfs_bg_flags_to_raid_index(type);
+ ncopies = btrfs_raid_array[raid_index].ncopies;
+ nparity = btrfs_raid_array[raid_index].nparity;
if (!num_stripes) {
chunk_err(leaf, chunk, logical,
"invalid chunk num_stripes, have %u", num_stripes);
return -EUCLEAN;
}
+ if (num_stripes < ncopies) {
+ chunk_err(leaf, chunk, logical,
+ "invalid chunk num_stripes < ncopies, have %u < %d",
+ num_stripes, ncopies);
+ return -EUCLEAN;
+ }
+ if (nparity && num_stripes == nparity) {
+ chunk_err(leaf, chunk, logical,
+ "invalid chunk num_stripes == nparity, have %u == %d",
+ num_stripes, nparity);
+ return -EUCLEAN;
+ }
if (!IS_ALIGNED(logical, fs_info->sectorsize)) {
chunk_err(leaf, chunk, logical,
"invalid chunk logical, have %llu should aligned to %u",
--
2.28.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] btrfs: Fix divide by zero
2020-10-09 1:09 [PATCH v2] btrfs: Fix divide by zero Daniel Xu
@ 2020-10-14 20:26 ` Daniel Xu
2020-10-14 20:44 ` Josef Bacik
2020-10-16 14:33 ` David Sterba
2 siblings, 0 replies; 4+ messages in thread
From: Daniel Xu @ 2020-10-14 20:26 UTC (permalink / raw)
To: linux-btrfs, dsterba; +Cc: Kernel Team, josef, quwenruo.btrfs, Qu Wenruo
On Thu, Oct 8, 2020, at 6:09 PM, Daniel Xu wrote:
> If there's no parity and num_stripes < ncopies, an btrfs image can
> trigger a divide by zero in calc_stripe_length().
>
> The image (see link) was generated through fuzzing.
>
> Reviewed-by: Qu Wenruo <wqu@suse.com>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=209587
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> ---
>
> v1->v2:
> * Upload test image to kernel bugzilla
>
>
> fs/btrfs/tree-checker.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
> index 7b1fee630f97..e03c3807921f 100644
> --- a/fs/btrfs/tree-checker.c
> +++ b/fs/btrfs/tree-checker.c
> @@ -760,18 +760,36 @@ int btrfs_check_chunk_valid(struct extent_buffer *leaf,
> u64 type;
> u64 features;
> bool mixed = false;
> + int raid_index;
> + int nparity;
> + int ncopies;
>
> length = btrfs_chunk_length(leaf, chunk);
> stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
> num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
> sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
> type = btrfs_chunk_type(leaf, chunk);
> + raid_index = btrfs_bg_flags_to_raid_index(type);
> + ncopies = btrfs_raid_array[raid_index].ncopies;
> + nparity = btrfs_raid_array[raid_index].nparity;
>
> if (!num_stripes) {
> chunk_err(leaf, chunk, logical,
> "invalid chunk num_stripes, have %u", num_stripes);
> return -EUCLEAN;
> }
> + if (num_stripes < ncopies) {
> + chunk_err(leaf, chunk, logical,
> + "invalid chunk num_stripes < ncopies, have %u < %d",
> + num_stripes, ncopies);
> + return -EUCLEAN;
> + }
> + if (nparity && num_stripes == nparity) {
> + chunk_err(leaf, chunk, logical,
> + "invalid chunk num_stripes == nparity, have %u == %d",
> + num_stripes, nparity);
> + return -EUCLEAN;
> + }
> if (!IS_ALIGNED(logical, fs_info->sectorsize)) {
> chunk_err(leaf, chunk, logical,
> "invalid chunk logical, have %llu should aligned to %u",
> --
> 2.28.0
>
>
Gentle poke.
Thanks,
Daniel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] btrfs: Fix divide by zero
2020-10-09 1:09 [PATCH v2] btrfs: Fix divide by zero Daniel Xu
2020-10-14 20:26 ` Daniel Xu
@ 2020-10-14 20:44 ` Josef Bacik
2020-10-16 14:33 ` David Sterba
2 siblings, 0 replies; 4+ messages in thread
From: Josef Bacik @ 2020-10-14 20:44 UTC (permalink / raw)
To: Daniel Xu, linux-btrfs; +Cc: kernel-team, quwenruo.btrfs, Qu Wenruo
On 10/8/20 9:09 PM, Daniel Xu wrote:
> If there's no parity and num_stripes < ncopies, an btrfs image can
> trigger a divide by zero in calc_stripe_length().
>
> The image (see link) was generated through fuzzing.
>
> Reviewed-by: Qu Wenruo <wqu@suse.com>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=209587
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Thanks,
Josef
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] btrfs: Fix divide by zero
2020-10-09 1:09 [PATCH v2] btrfs: Fix divide by zero Daniel Xu
2020-10-14 20:26 ` Daniel Xu
2020-10-14 20:44 ` Josef Bacik
@ 2020-10-16 14:33 ` David Sterba
2 siblings, 0 replies; 4+ messages in thread
From: David Sterba @ 2020-10-16 14:33 UTC (permalink / raw)
To: Daniel Xu; +Cc: linux-btrfs, kernel-team, josef, quwenruo.btrfs, Qu Wenruo
On Thu, Oct 08, 2020 at 06:09:10PM -0700, Daniel Xu wrote:
> If there's no parity and num_stripes < ncopies, an btrfs image can
> trigger a divide by zero in calc_stripe_length().
>
> The image (see link) was generated through fuzzing.
>
> Reviewed-by: Qu Wenruo <wqu@suse.com>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=209587
For bugzillas please use Bugzilla: tag.
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Please write more descriptive subjects like
"btrfs: tree-checker: validate number of chunk stripes and parity"
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-10-09 1:09 [PATCH v2] btrfs: Fix divide by zero Daniel Xu
2020-10-14 20:26 ` Daniel Xu
2020-10-14 20:44 ` Josef Bacik
2020-10-16 14:33 ` David Sterba
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