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* [PATCH] SecurityPkg: fix sha256 signature check
@ 2018-05-09 22:09 James Bottomley
  2018-05-10 12:36 ` Laszlo Ersek
  0 siblings, 1 reply; 3+ messages in thread
From: James Bottomley @ 2018-05-09 22:09 UTC (permalink / raw)
  To: edk2-devel@lists.01.org; +Cc: Zhang Lubo

commit c035e37335ae43229d7e68de74a65f2c01ebc0af
Author: Zhang Lubo <lubo.zhang@intel.com>
Date:   Thu Jan 5 14:58:05 2017 +0800

    SecurityPkg: enhance secure boot Config Dxe & Time Based AuthVariable.

Added a check for sha256 being the ownly allowed signature hash.
Unfortuantely this commit assumed the form of the signature data was a
raw SignedData sequence.  Most tools actually generate a ContentInfo
sequence instead which contains a header identifying the content as
pkcs7-SignedData.  Fix this check to allow either format to work.

This fix is needed at least for efitools because we generate signed
variable updates with the ContentInfo header.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---
 CryptoPkg/Library/OpensslLib/openssl              |  2 +-
 SecurityPkg/Library/AuthVariableLib/AuthService.c | 11 ++++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/CryptoPkg/Library/OpensslLib/openssl b/CryptoPkg/Library/OpensslLib/openssl
index b2758a2292..d4e4bd2a81 160000
--- a/CryptoPkg/Library/OpensslLib/openssl
+++ b/CryptoPkg/Library/OpensslLib/openssl
@@ -1 +1 @@
-Subproject commit b2758a2292aceda93e9f44c219b94fe21bb9a650
+Subproject commit d4e4bd2a8163f355fa8a3884077eaec7adc75ff7
diff --git a/SecurityPkg/Library/AuthVariableLib/AuthService.c b/SecurityPkg/Library/AuthVariableLib/AuthService.c
index 213a524f27..855ea3350a 100644
--- a/SecurityPkg/Library/AuthVariableLib/AuthService.c
+++ b/SecurityPkg/Library/AuthVariableLib/AuthService.c
@@ -1908,10 +1908,19 @@ VerifyTimeBasedPayload (
   //    in VARIABLE_AUTHENTICATION_2 descriptor.
   //    This field has the fixed offset (+13) and be calculated based on two bytes of length encoding.
   //
+  // However the data may also begin
+  //   ContentInfo ::= SEQUENCE {
+  //	   contentType ContentType,
+  //	   content
+  //	     [0] EXPLICIT ANY DEFINED BY contentType OPTIONAL }
+  //
+  // In which case the fixed offset is +32
+  //
   if ((Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0) {
     if (SigDataSize >= (13 + sizeof (mSha256OidValue))) {
       if (((*(SigData + 1) & TWO_BYTE_ENCODE) != TWO_BYTE_ENCODE) || 
-           (CompareMem (SigData + 13, &mSha256OidValue, sizeof (mSha256OidValue)) != 0)) {
+	  (CompareMem (SigData + 13, &mSha256OidValue, sizeof (mSha256OidValue)) != 0 &&
+	   CompareMem (SigData + 32, &mSha256OidValue, sizeof (mSha256OidValue)) != 0)) {
           return EFI_SECURITY_VIOLATION;
         }
     }
-- 
2.13.6



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Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2018-05-09 22:09 [PATCH] SecurityPkg: fix sha256 signature check James Bottomley
2018-05-10 12:36 ` Laszlo Ersek
2018-05-11  8:25   ` Long, Qin

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