[PATCH] crypto/openssl: fix warning on copy length

[Ruifeng Wang]

> -----Original Message-----
> From: David Marchand <david.marchand at redhat.com>
> Sent: Friday, January 6, 2023 6:27 PM
> To: Kai Ji <kai.ji at intel.com>; Ruifeng Wang <Ruifeng.Wang at arm.com>
> Cc: Fan Zhang <fanzhang.oss at gmail.com>; Akhil Goyal <gakhil at marvell.com>; dev at dpdk.org; nd
> <nd at arm.com>; stable at dpdk.org; Feifei Wang <Feifei.Wang2 at arm.com>
> Subject: Re: [PATCH] crypto/openssl: fix warning on copy length
> 
> On Fri, Jan 6, 2023 at 11:16 AM Ruifeng Wang <ruifeng.wang at arm.com> wrote:
> >
> > When building with gcc 11.2.0, the compiler warns as follows:
> > In function 'memcpy',
> >     inlined from 'openssl_set_session_auth_parameters'
> at ../drivers/crypto/openssl/rte_openssl_pmd.c:699:3,
> >     inlined from 'openssl_set_session_parameters'
> at ../drivers/crypto/openssl/rte_openssl_pmd.c:826:9:
> > /usr/include/aarch64-linux-gnu/bits/string_fortified.h:29:10: warning:
> '__builtin_memcpy' forming offset [4, 8] is out of the bounds [0, 4] [-Warray-bounds]
> >
> > Fixed the warning by copying up to string size.
> >
> > Fixes: 75adf1eae44f ("crypto/openssl: update HMAC routine with 3.0 EVP API")
> > Cc: stable at dpdk.org
> > Cc: kai.ji at intel.com
> >
> > Signed-off-by: Ruifeng Wang <ruifeng.wang at arm.com>
> > Reviewed-by: Feifei Wang <feifei.wang2 at arm.com>
> > ---
> >  drivers/crypto/openssl/rte_openssl_pmd.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/crypto/openssl/rte_openssl_pmd.c
> b/drivers/crypto/openssl/rte_openssl_pmd.c
> > index 05449b6e98..8458ad487a 100644
> > --- a/drivers/crypto/openssl/rte_openssl_pmd.c
> > +++ b/drivers/crypto/openssl/rte_openssl_pmd.c
> > @@ -696,7 +696,7 @@ openssl_set_session_auth_parameters(struct openssl_session *sess,
> >                 algo = digest_name_get(xform->auth.algo);
> >                 if (!algo)
> >                         return -EINVAL;
> > -               rte_memcpy(algo_name, algo, (sizeof(algo)+1));
> > +               rte_memcpy(algo_name, algo, strlen(algo) + 1);
> 
> Why is there a need for copying such a string to a local storage?

From OpenSSL document, I can see OSSL_PARAM_construct_utf8_string() takes a buffer
as input. But I'm not sure if a const is acceptable. 
I would keep the fix simple for backport. Removing copy is an improvement that
can be done by someone who has more knowledge of OpenSSL library.
> 
> If it is really needed, we are dealing with strings, so I suggest:
> strlcpy(algo_name, algo, sizeof(algo_name));

Thanks for the suggestion. Will update in v2.

Regards,
Ruifeng
> 
> 
> --
> David Marchand