Ensure ctx is zero-initialized, such that the encl_measure function will
not call EVP_MD_CTX_destroy with an uninitialized ctx pointer in case of an
early error during key generation.

Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
---
 tools/testing/selftests/sgx/sigstruct.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/sgx/sigstruct.c b/tools/testing/selftests/sgx/sigstruct.c
index a07896a46364..dd1fdab90e26 100644
--- a/tools/testing/selftests/sgx/sigstruct.c
+++ b/tools/testing/selftests/sgx/sigstruct.c
@@ -318,9 +318,9 @@ bool encl_measure(struct encl *encl)
 	struct sgx_sigstruct *sigstruct = &encl->sigstruct;
 	struct sgx_sigstruct_payload payload;
 	uint8_t digest[SHA256_DIGEST_LENGTH];
+	EVP_MD_CTX *ctx = NULL;
 	unsigned int siglen;
 	RSA *key = NULL;
-	EVP_MD_CTX *ctx;
 	int i;
 
 	memset(sigstruct, 0, sizeof(*sigstruct));
-- 
2.34.1

On Mon, 2023-07-24 at 18:58 +0200, Jo Van Bulck wrote:
> Ensure ctx is zero-initialized, such that the encl_measure function will
> not call EVP_MD_CTX_destroy with an uninitialized ctx pointer in case of an
> early error during key generation.
> 
> Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
> ---
>  tools/testing/selftests/sgx/sigstruct.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/sgx/sigstruct.c b/tools/testing/selftests/sgx/sigstruct.c
> index a07896a46364..dd1fdab90e26 100644
> --- a/tools/testing/selftests/sgx/sigstruct.c
> +++ b/tools/testing/selftests/sgx/sigstruct.c
> @@ -318,9 +318,9 @@ bool encl_measure(struct encl *encl)
>  	struct sgx_sigstruct *sigstruct = &encl->sigstruct;
>  	struct sgx_sigstruct_payload payload;
>  	uint8_t digest[SHA256_DIGEST_LENGTH];
> +	EVP_MD_CTX *ctx = NULL;
>  	unsigned int siglen;
>  	RSA *key = NULL;
> -	EVP_MD_CTX *ctx;
>  	int i;
>  
>  	memset(sigstruct, 0, sizeof(*sigstruct));

Is it safe to assume EVP_MD_CTX_destroy() can always handle a NULL ctx?

The manpage says:

EVP_MD_CTX_destroy() cleans up digest context ctx and frees up the space
allocated to it, it should be called only on a context created using
EVP_MD_CTX_create().

On 03.08.23 05:51, Huang, Kai wrote:
> Is it safe to assume EVP_MD_CTX_destroy() can always handle a NULL ctx?
> 
> The manpage says:
> 
> EVP_MD_CTX_destroy() cleans up digest context ctx and frees up the space
> allocated to it, it should be called only on a context created using
> EVP_MD_CTX_create().

Thank you for pointing this out. Afais the implementations I've seen can 
handle NULL, and similar error-handling paths exists where 
EVP_MD_CTX_destroy() is called with a NULL pointer exist in several 
places in the openSSL code.

That being said, this indeed not explicit in the specification (unlike 
RSA_free() which is called just after and explicitly specifies that NULL 
is okay). So you're probably right that it's generally safer to not call 
EVP_MD_CTX_destroy() with a NULL pointer.

I'll include an extra check for this in the next patch revision.

On Mon Jul 24, 2023 at 4:58 PM UTC, Jo Van Bulck wrote:
> Ensure ctx is zero-initialized, such that the encl_measure function will
> not call EVP_MD_CTX_destroy with an uninitialized ctx pointer in case of an
> early error during key generation.
>
> Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
> ---
>  tools/testing/selftests/sgx/sigstruct.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/sgx/sigstruct.c b/tools/testing/selftests/sgx/sigstruct.c
> index a07896a46364..dd1fdab90e26 100644
> --- a/tools/testing/selftests/sgx/sigstruct.c
> +++ b/tools/testing/selftests/sgx/sigstruct.c
> @@ -318,9 +318,9 @@ bool encl_measure(struct encl *encl)
>  	struct sgx_sigstruct *sigstruct = &encl->sigstruct;
>  	struct sgx_sigstruct_payload payload;
>  	uint8_t digest[SHA256_DIGEST_LENGTH];
> +	EVP_MD_CTX *ctx = NULL;
>  	unsigned int siglen;
>  	RSA *key = NULL;
> -	EVP_MD_CTX *ctx;
>  	int i;
>  
>  	memset(sigstruct, 0, sizeof(*sigstruct));
> -- 
> 2.34.1

Add a fixes tag. In other words, find the commit ID that caused the issue
and add the output of the following to this patch before your sob:

git --no-pager log --format='Fixes: %h ("%s")' --abbrev=12 -1 <commit ID>;

BR, Jarkko

On 28.07.23 21:03, Jarkko Sakkinen wrote:
> Add a fixes tag. In other words, find the commit ID that caused the issue
> and add the output of the following to this patch before your sob:
> 
> git --no-pager log --format='Fixes: %h ("%s")' --abbrev=12 -1 <commit ID>;
> 
> BR, Jarkko

Thank you, added for the next patch revision.

On Mon Jul 24, 2023 at 4:58 PM UTC, Jo Van Bulck wrote:
> Ensure ctx is zero-initialized, such that the encl_measure function will
> not call EVP_MD_CTX_destroy with an uninitialized ctx pointer in case of an
> early error during key generation.
>
> Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
> ---
>  tools/testing/selftests/sgx/sigstruct.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/sgx/sigstruct.c b/tools/testing/selftests/sgx/sigstruct.c
> index a07896a46364..dd1fdab90e26 100644
> --- a/tools/testing/selftests/sgx/sigstruct.c
> +++ b/tools/testing/selftests/sgx/sigstruct.c
> @@ -318,9 +318,9 @@ bool encl_measure(struct encl *encl)
>  	struct sgx_sigstruct *sigstruct = &encl->sigstruct;
>  	struct sgx_sigstruct_payload payload;
>  	uint8_t digest[SHA256_DIGEST_LENGTH];
> +	EVP_MD_CTX *ctx = NULL;
>  	unsigned int siglen;
>  	RSA *key = NULL;
> -	EVP_MD_CTX *ctx;
>  	int i;
>  
>  	memset(sigstruct, 0, sizeof(*sigstruct));
> -- 
> 2.34.1

Ditto.

BR, Jarkko