AuthenticodeVerify() calls OpenSSLs d2i_PKCS7() API to parse asn encoded
signed authenticode pkcs#7 data. when this successfully returns, a type
check is done by calling PKCS7_type_is_signed() and then
Pkcs7->d.sign->contents->type is used. It is possible to construct an asn1
blob that successfully decodes and have d2i_PKCS7() return a valid pointer
and have PKCS7_type_is_signed() also return success but have Pkcs7->d.sign
be a NULL pointer.
Looking at how PKCS7_verify() [inside of OpenSSL] implements checking for
pkcs7 structs it does the following:
- call PKCS7_type_is_signed()
- call PKCS7_get_detached()
Looking into how PKCS7_get_detatched() is implemented, it checks to see if
p7->d.sign is NULL or if p7->d.sign->contents->d.ptr is NULL.
As such, the fix is to do the same as OpenSSL after calling d2i_PKCS7().
- Add call to PKS7_get_detached() to existing error handling
Cc: Xiaoyu Lu <xiaoyux.lu@intel.com> Cc: Guomin Jiang <guomin.jiang@intel.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Jian J Wang <jian.j.wang@intel.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>