2019-07-11 19:29:33

by Wenwen Wang

Subject: [PATCH v2] block/bio-integrity: fix a memory leak bug

From: Wenwen Wang <[email protected]>

In bio_integrity_prep(), a kernel buffer is allocated through kmalloc() to
hold integrity metadata. Later on, the buffer will be attached to the bio
structure through bio_integrity_add_page(), which returns the number of
bytes of integrity metadata attached. Due to unexpected situations,
bio_integrity_add_page() may return 0. As a result, bio_integrity_prep()
needs to be terminated with 'false' returned to indicate this error.
However, the allocated kernel buffer is not freed on this execution path,
leading to a memory leak.

To fix this issue, free the allocated buffer before returning from
bio_integrity_prep().

Signed-off-by: Wenwen Wang <[email protected]>
---
block/bio-integrity.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 4db6208..fb95dbb 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -276,8 +276,12 @@ bool bio_integrity_prep(struct bio *bio)
ret = bio_integrity_add_page(bio, virt_to_page(buf),
bytes, offset);

- if (ret == 0)
- return false;
+ if (ret == 0) {
+ printk(KERN_ERR "could not attach integrity payload\n");
+ kfree(buf);
+ status = BLK_STS_RESOURCE;
+ goto err_end_io;
+ }

if (ret < bytes)
break;
--
2.7.4

2019-07-12 00:35:02

by Ming Lei

Subject: Re: [PATCH v2] block/bio-integrity: fix a memory leak bug

On Fri, Jul 12, 2019 at 3:29 AM Wenwen Wang <[email protected]> wrote:
>
> From: Wenwen Wang <[email protected]>
>
> In bio_integrity_prep(), a kernel buffer is allocated through kmalloc() to
> hold integrity metadata. Later on, the buffer will be attached to the bio
> structure through bio_integrity_add_page(), which returns the number of
> bytes of integrity metadata attached. Due to unexpected situations,
> bio_integrity_add_page() may return 0. As a result, bio_integrity_prep()
> needs to be terminated with 'false' returned to indicate this error.
> However, the allocated kernel buffer is not freed on this execution path,
> leading to a memory leak.
>
> To fix this issue, free the allocated buffer before returning from
> bio_integrity_prep().
>
> Signed-off-by: Wenwen Wang <[email protected]>
> ---
> block/bio-integrity.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/block/bio-integrity.c b/block/bio-integrity.c
> index 4db6208..fb95dbb 100644
> --- a/block/bio-integrity.c
> +++ b/block/bio-integrity.c
> @@ -276,8 +276,12 @@ bool bio_integrity_prep(struct bio *bio)
> ret = bio_integrity_add_page(bio, virt_to_page(buf),
> bytes, offset);
>
> - if (ret == 0)
> - return false;
> + if (ret == 0) {
> + printk(KERN_ERR "could not attach integrity payload\n");
> + kfree(buf);
> + status = BLK_STS_RESOURCE;
> + goto err_end_io;
> + }
>
> if (ret < bytes)
> break;

Looks fine:

Reviewed-by: Ming Lei <[email protected]>


Thanks,
Ming Lei

2019-07-12 01:29:02

by Martin K. Petersen

Subject: Re: [PATCH v2] block/bio-integrity: fix a memory leak bug

Wenwen,

> To fix this issue, free the allocated buffer before returning from
> bio_integrity_prep().

Acked-by: Martin K. Petersen <[email protected]>

--
Martin K. Petersen Oracle Linux Engineering

2019-07-12 02:03:37

by Jens Axboe

Subject: Re: [PATCH v2] block/bio-integrity: fix a memory leak bug

On 7/11/19 1:22 PM, Wenwen Wang wrote:
> From: Wenwen Wang <[email protected]>
>
> In bio_integrity_prep(), a kernel buffer is allocated through kmalloc() to
> hold integrity metadata. Later on, the buffer will be attached to the bio
> structure through bio_integrity_add_page(), which returns the number of
> bytes of integrity metadata attached. Due to unexpected situations,
> bio_integrity_add_page() may return 0. As a result, bio_integrity_prep()
> needs to be terminated with 'false' returned to indicate this error.
> However, the allocated kernel buffer is not freed on this execution path,
> leading to a memory leak.
>
> To fix this issue, free the allocated buffer before returning from
> bio_integrity_prep().

Applied, thanks.

--
Jens Axboe