The argument of scatterwalk_unmap() is supposed to be the void* that was
returned by the previous scatterwalk_map() call.
The s390 AES-GCM implementation was instead passing the pointer to the
struct scatter_walk.

This doesn't actually break anything because scatterwalk_unmap() only uses
its argument under CONFIG_HIGHMEM and ARCH_HAS_FLUSH_ON_KUNMAP.

Note that I have not tested this patch in any way, not even compile-tested
it.

Fixes: bf7fa038707c ("s390/crypto: add s390 platform specific aes gcm support.")
Signed-off-by: Jann Horn <jannh@google.com>
---
IDK which tree this has to go through - s390 or crypto?
maybe s390 is better, since they can actually test it?

 arch/s390/crypto/aes_s390.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
index 54c7536f2482..1023e9d43d44 100644
--- a/arch/s390/crypto/aes_s390.c
+++ b/arch/s390/crypto/aes_s390.c
@@ -701,7 +701,7 @@ static inline void _gcm_sg_unmap_and_advance(struct gcm_sg_walk *gw,
 					     unsigned int nbytes)
 {
 	gw->walk_bytes_remain -= nbytes;
-	scatterwalk_unmap(&gw->walk);
+	scatterwalk_unmap(gw->walk_ptr);
 	scatterwalk_advance(&gw->walk, nbytes);
 	scatterwalk_done(&gw->walk, 0, gw->walk_bytes_remain);
 	gw->walk_ptr = NULL;
@@ -776,7 +776,7 @@ static int gcm_out_walk_go(struct gcm_sg_walk *gw, unsigned int minbytesneeded)
 		goto out;
 	}
 
-	scatterwalk_unmap(&gw->walk);
+	scatterwalk_unmap(gw->walk_ptr);
 	gw->walk_ptr = NULL;
 
 	gw->ptr = gw->buf;

base-commit: 42226c989789d8da4af1de0c31070c96726d990c
-- 
2.36.0.550.gb090851708-goog

On Tue, May 17, 2022 at 04:30:47PM +0200, Jann Horn wrote:
> The argument of scatterwalk_unmap() is supposed to be the void* that was
> returned by the previous scatterwalk_map() call.
> The s390 AES-GCM implementation was instead passing the pointer to the
> struct scatter_walk.
> 
> This doesn't actually break anything because scatterwalk_unmap() only uses
> its argument under CONFIG_HIGHMEM and ARCH_HAS_FLUSH_ON_KUNMAP.
> 
> Note that I have not tested this patch in any way, not even compile-tested
> it.
> 
> Fixes: bf7fa038707c ("s390/crypto: add s390 platform specific aes gcm support.")
> Signed-off-by: Jann Horn <jannh@google.com>
> ---
> IDK which tree this has to go through - s390 or crypto?
> maybe s390 is better, since they can actually test it?

Applied to s390 tree. Thanks!

On Tue, May 17, 2022 at 04:30:47PM +0200, Jann Horn wrote:
> The argument of scatterwalk_unmap() is supposed to be the void* that was
> returned by the previous scatterwalk_map() call.
> The s390 AES-GCM implementation was instead passing the pointer to the
> struct scatter_walk.
> 
> This doesn't actually break anything because scatterwalk_unmap() only uses
> its argument under CONFIG_HIGHMEM and ARCH_HAS_FLUSH_ON_KUNMAP.
> 
> Note that I have not tested this patch in any way, not even compile-tested
> it.
> 
> Fixes: bf7fa038707c ("s390/crypto: add s390 platform specific aes gcm support.")
> Signed-off-by: Jann Horn <jannh@google.com>
> ---
> IDK which tree this has to go through - s390 or crypto?
> maybe s390 is better, since they can actually test it?
> 
>  arch/s390/crypto/aes_s390.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

This can go via the s390 tree, however I'd like to have an ACK from
Harald, who wrote the original code.

> diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
> index 54c7536f2482..1023e9d43d44 100644
> --- a/arch/s390/crypto/aes_s390.c
> +++ b/arch/s390/crypto/aes_s390.c
> @@ -701,7 +701,7 @@ static inline void _gcm_sg_unmap_and_advance(struct gcm_sg_walk *gw,
>  					     unsigned int nbytes)
>  {
>  	gw->walk_bytes_remain -= nbytes;
> -	scatterwalk_unmap(&gw->walk);
> +	scatterwalk_unmap(gw->walk_ptr);
>  	scatterwalk_advance(&gw->walk, nbytes);
>  	scatterwalk_done(&gw->walk, 0, gw->walk_bytes_remain);
>  	gw->walk_ptr = NULL;
> @@ -776,7 +776,7 @@ static int gcm_out_walk_go(struct gcm_sg_walk *gw, unsigned int minbytesneeded)
>  		goto out;
>  	}
>  
> -	scatterwalk_unmap(&gw->walk);
> +	scatterwalk_unmap(gw->walk_ptr);
>  	gw->walk_ptr = NULL;
>  
>  	gw->ptr = gw->buf;
> 
> base-commit: 42226c989789d8da4af1de0c31070c96726d990c
> -- 
> 2.36.0.550.gb090851708-goog
>