Re: [PATCH] SecurityPkg/Tpm2Help.c: Add boundary check for array

["Yao, Jiewen" <jiewen.yao@intel.com>]

Hi
May I know where is the data from? Trusted region or non-trusted region?

I am thinking if we need use ASSERT to avoid user mistake.
But want to check the API input assumption at first...



> -----Original Message-----
> From: Zhang, Shenglei <shenglei.zhang@intel.com>
> Sent: Friday, December 6, 2019 9:50 AM
> To: devel@edk2.groups.io
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Wang, Jian J <jian.j.wang@intel.com>;
> Zhang, Chao B <chao.b.zhang@intel.com>
> Subject: [PATCH] SecurityPkg/Tpm2Help.c: Add boundary check for array
> 
> Add 'Index < HASH_COUNT' to ensure things out of boundary
> of digests[] can not be visited.
> 
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Chao Zhang <chao.b.zhang@intel.com>
> Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
> ---
>  SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c
> b/SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c
> index 36c240d1221c..a7d4e3ab5373 100644
> --- a/SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c
> +++ b/SecurityPkg/Library/Tpm2CommandLib/Tpm2Help.c
> @@ -299,7 +299,7 @@ GetDigestListSize (
>    UINT32 TotalSize;
> 
>    TotalSize = sizeof(DigestList->count);
> -  for (Index = 0; Index < DigestList->count; Index++) {
> +  for (Index = 0; Index < DigestList->count, Index < HASH_COUNT; Index++) {
>      DigestSize = GetHashSizeFromAlgo (DigestList->digests[Index].hashAlg);
>      TotalSize += sizeof(DigestList->digests[Index].hashAlg) + DigestSize;
>    }
> --
> 2.18.0.windows.1