Re: [PATCH v2] crypto: asymmetric_keys: fix uninitialized pointers with free attribute

[Ignat Korchagin]

On Tue, Nov 11, 2025 at 1:36 PM Ally Heev <allyheev@xxxxxxxxx> wrote:
>
> Uninitialized pointers with `__free` attribute can cause undefined
> behavior as the memory assigned randomly to the pointer is freed
> automatically when the pointer goes out of scope.
>
> crypto/asymmetric_keys doesn't have any bugs related to this as of now,
> but, it is better to initialize and assign pointers with `__free`
> attribute in one statement to ensure proper scope-based cleanup
>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://lore.kernel.org/all/aPiG_F5EBQUjZqsl@stanley.mountain/
> Signed-off-by: Ally Heev <allyheev@xxxxxxxxx>

Reviewed-by: Ignat Korchagin <ignat@xxxxxxxxxxxxxx>

> ---
> Changes in v2:
> - moved declarations to the top and initialized them with NULL
> - Link to v1: https://lore.kernel.org/r/20251105-aheev-uninitialized-free-attr-crypto-v1-1-83da1e10e8c4@xxxxxxxxx
> ---
>  crypto/asymmetric_keys/x509_cert_parser.c | 2 +-
>  crypto/asymmetric_keys/x509_public_key.c  | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
> index 8df3fa60a44f80fbd71af17faeca2e92b6cc03ce..b37cae914987b69c996d6559058c00f13c92b5b9 100644
> --- a/crypto/asymmetric_keys/x509_cert_parser.c
> +++ b/crypto/asymmetric_keys/x509_cert_parser.c
> @@ -60,7 +60,7 @@ EXPORT_SYMBOL_GPL(x509_free_certificate);
>   */
>  struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
>  {
> -       struct x509_certificate *cert __free(x509_free_certificate);
> +       struct x509_certificate *cert __free(x509_free_certificate) = NULL;
>         struct x509_parse_context *ctx __free(kfree) = NULL;
>         struct asymmetric_key_id *kid;
>         long ret;
> diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
> index 8409d7d36cb4f3582e15f9ee4d25f302b3b29358..12e3341e806b8db93803325a96a3821fd5d0a9f0 100644
> --- a/crypto/asymmetric_keys/x509_public_key.c
> +++ b/crypto/asymmetric_keys/x509_public_key.c
> @@ -148,7 +148,7 @@ int x509_check_for_self_signed(struct x509_certificate *cert)
>   */
>  static int x509_key_preparse(struct key_preparsed_payload *prep)
>  {
> -       struct x509_certificate *cert __free(x509_free_certificate);
> +       struct x509_certificate *cert __free(x509_free_certificate) = NULL;
>         struct asymmetric_key_ids *kids __free(kfree) = NULL;
>         char *p, *desc __free(kfree) = NULL;
>         const char *q;
>
> ---
> base-commit: c9cfc122f03711a5124b4aafab3211cf4d35a2ac
> change-id: 20251105-aheev-uninitialized-free-attr-crypto-bc94ec1b2253
>
> Best regards,
> --
> Ally Heev <allyheev@xxxxxxxxx>
>