Re: [PATCH] CryptoPkg/BaseCryptLib: Add NULL pointer checks in DH and P7Verify

["Wu, Hao A" <hao.a.wu@intel.com>]

Reviewed-by: Hao Wu <hao.a.wu@intel.com>


Best Regards,
Hao Wu


> -----Original Message-----
> From: Long, Qin
> Sent: Friday, May 19, 2017 3:27 PM
> To: Ye, Ting; Wu, Hao A; edk2-devel@lists.01.org
> Cc: Long, Qin
> Subject: [PATCH] CryptoPkg/BaseCryptLib: Add NULL pointer checks in DH and
> P7Verify
> 
> Add more NULL pointer checks before using them in DhGenerateKey and
> Pkcs7GetCertificatesList functions to eliminate possible dereferenced
> pointer issue.
> 
> Cc: Ting Ye <ting.ye@intel.com>
> Cc: Hao Wu <hao.a.wu@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Qin Long <qin.long@intel.com>
> ---
>  CryptoPkg/Library/BaseCryptLib/Pk/CryptDh.c          |  4 +++-
>  CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7Verify.c | 10 +++++++---
>  2 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/CryptoPkg/Library/BaseCryptLib/Pk/CryptDh.c
> b/CryptoPkg/Library/BaseCryptLib/Pk/CryptDh.c
> index f44684f907..391efd5c14 100644
> --- a/CryptoPkg/Library/BaseCryptLib/Pk/CryptDh.c
> +++ b/CryptoPkg/Library/BaseCryptLib/Pk/CryptDh.c
> @@ -232,7 +232,9 @@ DhGenerateKey (
>        return FALSE;
>      }
> 
> -    BN_bn2bin (DhPubKey, PublicKey);
> +    if (PublicKey != NULL) {
> +      BN_bn2bin (DhPubKey, PublicKey);
> +    }
>      *PublicKeySize = Size;
>    }
> 
> diff --git a/CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7Verify.c
> b/CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7Verify.c
> index 45d5df5e11..d564591cb7 100644
> --- a/CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7Verify.c
> +++ b/CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7Verify.c
> @@ -558,7 +558,9 @@ Pkcs7GetCertificatesList (
>      }
>    }
>    CtxUntrusted = X509_STORE_CTX_get0_untrusted (CertCtx);
> -  (VOID)sk_X509_delete_ptr (CtxUntrusted, Signer);
> +  if (CtxUntrusted != NULL) {
> +    (VOID)sk_X509_delete_ptr (CtxUntrusted, Signer);
> +  }
> 
>    //
>    // Build certificates stack chained from Signer's certificate.
> @@ -711,8 +713,10 @@ _Error:
>    }
>    sk_X509_free (Signers);
> 
> -  X509_STORE_CTX_cleanup (CertCtx);
> -  X509_STORE_CTX_free (CertCtx);
> +  if (CertCtx != NULL) {
> +    X509_STORE_CTX_cleanup (CertCtx);
> +    X509_STORE_CTX_free (CertCtx);
> +  }
> 
>    if (SingleCert != NULL) {
>      free (SingleCert);
> --
> 2.12.2.windows.2