[PATCH] SecurityPkg/Library/HashLibBaseCryptoRouter: Fix NULL_RETURNS Coverity issue

[PATCH] SecurityPkg/Library/HashLibBaseCryptoRouter: Fix NULL_RETURNS Coverity issue

[Ranbir Singh]

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In file SecurityPkg/Library/HashLibBaseCryptoRouter/
HashLibBaseCryptoRouterPei.c, the function
CheckSupportedHashMaskMismatch calls InternalGetHashInterfaceHob and
stores return value in HashInterfaceHobLast. Thereafter, it does

ASSERT (HashInterfaceHobLast != NULL);

but this comes into play only in DEBUG mode. In Release mode, the
code continues to proceed to dereferencing "HashInterfaceHobLast"
which will lead to CRASH if HashInterfaceHobLast is NULL.

Hence, for safety add HashInterfaceHobLast NULL pointer check before
accessing further field values.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4225
Signed-off-by: Ranbir Singh <Ranbir.Singh3@Dell.com>
---
.../HashLibBaseCryptoRouter/HashLibBaseCryptoRouterPei.c       | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/SecurityPkg/Library/HashLibBaseCryptoRouter/HashLibBaseCryptoRouterPei.c b/SecurityPkg/Library/HashLibBaseCryptoRouter/HashLibBaseCryptoRouterPei.c
index eeb424b6c3..0c8315ed03 100644
--- a/SecurityPkg/Library/HashLibBaseCryptoRouter/HashLibBaseCryptoRouterPei.c
+++ b/SecurityPkg/Library/HashLibBaseCryptoRouter/HashLibBaseCryptoRouterPei.c
@@ -108,7 +108,8 @@ CheckSupportedHashMaskMismatch (
HashInterfaceHobLast = InternalGetHashInterfaceHob (&gZeroGuid);
ASSERT (HashInterfaceHobLast != NULL);

-  if ((HashInterfaceHobLast->SupportedHashMask != 0) &&
+  if ((HashInterfaceHobLast != NULL) &&
+      (HashInterfaceHobLast->SupportedHashMask != 0) &&
(HashInterfaceHobCurrent->SupportedHashMask != HashInterfaceHobLast->SupportedHashMask))
{
DEBUG ((
--
2.36.1.windows.1

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