Re: [PATCH] s390/crypto: fix scatterwalk_unmap() callers in AES-GCM

Harald Freudenberger
2022-05-18T06:51:57Z

On 2022-05-17 20:01, Heiko Carstens wrote:
> 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
>>
Give me a chance to test this and when the testcases all pass, I'll give
a green light....