[PATCH] net: Fix from address in memcpy_to_iter_csum()

[PATCH] net: Fix from address in memcpy_to_iter_csum()

[Michael Lass]

While inlining csum_and_memcpy() into memcpy_to_iter_csum(), the from
address passed to csum_partial_copy_nocheck() was accidentally changed.
This causes a regression in applications using UDP, as for example
OpenAFS, causing loss of datagrams.

Fixes: dc32bff195b4 ("iov_iter, net: Fold in csum_and_memcpy()")
Cc: David Howells <dhowells@redhat.com>
Cc: stable@vger.kernel.org
Cc: regressions@lists.linux.dev
Signed-off-by: Michael Lass <bevan@bi-co.net>
---
 net/core/datagram.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/datagram.c b/net/core/datagram.c
index 103d46fa0eeb..a8b625abe242 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -751,7 +751,7 @@ size_t memcpy_to_iter_csum(void *iter_to, size_t progress,
 			   size_t len, void *from, void *priv2)
 {
 	__wsum *csum = priv2;
-	__wsum next = csum_partial_copy_nocheck(from, iter_to, len);
+	__wsum next = csum_partial_copy_nocheck(from + progress, iter_to, len);
 
 	*csum = csum_block_add(*csum, next, progress);
 	return 0;
-- 
2.43.0

Re: [PATCH] net: Fix from address in memcpy_to_iter_csum()

[Jeffrey E Altman]

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On 1/31/2024 10:52 AM, Michael Lass wrote:
> While inlining csum_and_memcpy() into memcpy_to_iter_csum(), the from
> address passed to csum_partial_copy_nocheck() was accidentally changed.
> This causes a regression in applications using UDP, as for example
> OpenAFS, causing loss of datagrams.
>
> Fixes: dc32bff195b4 ("iov_iter, net: Fold in csum_and_memcpy()")
> Cc: David Howells<dhowells@redhat.com>
> Cc:stable@vger.kernel.org
> Cc:regressions@lists.linux.dev
> Signed-off-by: Michael Lass<bevan@bi-co.net>
> ---
>   net/core/datagram.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/core/datagram.c b/net/core/datagram.c
> index 103d46fa0eeb..a8b625abe242 100644
> --- a/net/core/datagram.c
> +++ b/net/core/datagram.c
> @@ -751,7 +751,7 @@ size_t memcpy_to_iter_csum(void *iter_to, size_t progress,
>   			   size_t len, void *from, void *priv2)
>   {
>   	__wsum *csum = priv2;
> -	__wsum next = csum_partial_copy_nocheck(from, iter_to, len);
> +	__wsum next = csum_partial_copy_nocheck(from + progress, iter_to, len);
>   
>   	*csum = csum_block_add(*csum, next, progress);
>   	return 0;

Reviewed-by: Jeffrey Altman <jaltman@auristor.com>

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Re: [PATCH] net: Fix from address in memcpy_to_iter_csum()

[David Howells]

Michael Lass <bevan@bi-co.net> wrote:

> While inlining csum_and_memcpy() into memcpy_to_iter_csum(), the from
> address passed to csum_partial_copy_nocheck() was accidentally changed.
> This causes a regression in applications using UDP, as for example
> OpenAFS, causing loss of datagrams.
> 
> Fixes: dc32bff195b4 ("iov_iter, net: Fold in csum_and_memcpy()")
> Cc: David Howells <dhowells@redhat.com>
> Cc: stable@vger.kernel.org
> Cc: regressions@lists.linux.dev
> Signed-off-by: Michael Lass <bevan@bi-co.net>

Acked-by: David Howells <dhowells@redhat.com>

Re: [PATCH] net: Fix from address in memcpy_to_iter_csum()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Wed, 31 Jan 2024 16:52:20 +0100 you wrote:
> While inlining csum_and_memcpy() into memcpy_to_iter_csum(), the from
> address passed to csum_partial_copy_nocheck() was accidentally changed.
> This causes a regression in applications using UDP, as for example
> OpenAFS, causing loss of datagrams.
> 
> Fixes: dc32bff195b4 ("iov_iter, net: Fold in csum_and_memcpy()")
> Cc: David Howells <dhowells@redhat.com>
> Cc: stable@vger.kernel.org
> Cc: regressions@lists.linux.dev
> Signed-off-by: Michael Lass <bevan@bi-co.net>
> 
> [...]

Here is the summary with links:
  - net: Fix from address in memcpy_to_iter_csum()
    https://git.kernel.org/netdev/net/c/fe92f874f091

You are awesome, thank you!
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