Re: [PATCH] stubdom: Fix GCC 14 -Wmemset-elt-size compiler warnings in PolarSSL

[Andrew Precious <andrewprecious388@xxxxxxxxx>]

I was at first deliberating whether to send further patches because the current successor of PolarSSL is MbedTLS. Polarssl is now legacy & not maintained(polarssl was acquired by ARM).
Options:
1. Continual patching/maintaining a legacy library.
2. Upgrade to MbedTLS which will require alot of API changes.

On Wed, Aug 26, 2026 at 9:33 AM Jan Beulich <jbeulich@xxxxxxxx> wrote:

On 25.08.2026 20:46, Andrew Mbugua wrote:
> When compiling Xen with GCC 14, I get a compiler warning originating from the /polarssl-x86_64/library about a memset element size mismatch:
>
> ssl_tls.c: In function ‘ssl_session_reset’:
> ssl_tls.c:1778:5: warning: ‘memset’ used with length equal to number of elements without multiplication by element size [-Wmemset-elt-size]
> 1778 |     memset( ssl->ctx_enc, 0, 128 );
> |     ^~~~~~
> ssl_tls.c:1779:5: warning: ‘memset’ used with length equal to number of elements without multiplication by element size [-Wmemset-elt-size]
> 1779 |     memset( ssl->ctx_dec, 0, 128 );
> |     ^~~~~~
>
> This patch introduces a build-time patch to PolarSSL that replaces the hardcoded 128 byte length with a dynamic sizeof(), thus allowing clean compilation without warnings.

First a formal note: Commit messages want limiting to 75 characters per
line (some even say 72).

Then: You introduce a patch which isn't used anywhere. What use is such
a patch? You also ...

> Signed-off-by: Andrew Mbugua <andrewprecious388@xxxxxxxxx>
> ---
>  stubdom/patches/polarssl-gcc14-memset.patch | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
>  create mode 100644 stubdom/patches/polarssl-gcc14-memset.patch

... introduce it in a new patches/ subdir, when all other patches live
right beneath stubdom/.

> --- /dev/null
> +++ b/stubdom/patches/polarssl-gcc14-memset.patch
> @@ -0,0 +1,13 @@
> +--- a/library/ssl_tls.c
> ++++ b/library/ssl_tls.c
> +@@ -1775,8 +1775,8 @@
> +     memset( ssl->iv_dec, 0, 16 );
> +     memset( ssl->mac_enc, 0, 32 );
> +     memset( ssl->mac_dec, 0, 32 );
> +-    memset( ssl->ctx_enc, 0, 128 );
> +-    memset( ssl->ctx_dec, 0, 128 );
> ++    memset( ssl->ctx_enc, 0, sizeof( *ssl->ctx_enc) );
> ++    memset( ssl->ctx_dec, 0, sizeof( *ssl->ctx_dec) );

Don't you mean sizeof(ssl->ctx_enc) and sizeof(ssl->ctx_dec) respectively?
Otherwise it looks like you're making a bad situation worse.

Judging from surrounding style, there also looks to be a blank missing each,
ahead of the new inner closing parenthesis.

Jan