[PATCH v2 3/6] MdePkg/Rng: Add GUIDs to describe Rng algorithms

["PierreGondois" <pierre.gondois@arm.com>]

From: Pierre Gondois <pierre.gondois@arm.com>

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4441

The EFI_RNG_PROTOCOL can rely on the RngLib. The RngLib has multiple
implementations, some of them are unsafe (e.g. BaseRngLibTimerLib).
To allow the RngDxe to detect when such implementation is used,
a GetRngGuid() function is added in a following patch.

Prepare GetRngGuid() return values and add GUIDs describing
Rng algorithms:
- gEfiRngAlgorithmArmRndr
to describe a Rng algorithm accessed through Arm's RNDR instruction.
[1] states that the implementation of this algorithm should be
compliant to NIST SP900-80. The compliance is not guaranteed.
- gEfiRngAlgorithmUnSafe
to describe an unsafe implementation, cf. the BaseRngLibTimerLib.

[1] Arm Architecture Reference Manual Armv8, for A-profile architecture
sK12.1 'Properties of the generated random number'

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
---
 MdePkg/Include/Protocol/Rng.h | 20 ++++++++++++++++++++
 MdePkg/MdePkg.dec             |  2 ++
 2 files changed, 22 insertions(+)

diff --git a/MdePkg/Include/Protocol/Rng.h b/MdePkg/Include/Protocol/Rng.h
index baf425587b3c..dfdaf36e41dc 100644
--- a/MdePkg/Include/Protocol/Rng.h
+++ b/MdePkg/Include/Protocol/Rng.h
@@ -67,6 +67,24 @@ typedef EFI_GUID EFI_RNG_ALGORITHM;
   { \
     0xe43176d7, 0xb6e8, 0x4827, {0xb7, 0x84, 0x7f, 0xfd, 0xc4, 0xb6, 0x85, 0x61 } \
   }
+///
+/// The Arm Architecture states the RNDR that the DRBG algorithm should be compliant
+/// with NIST SP800-90A, while not mandating a particular algorithm, so as to be
+/// inclusive of different geographies.
+///
+#define EFI_RNG_ALGORITHM_ARM_RNDR \
+  { \
+    0x43d2fde3, 0x9d4e, 0x4d79,  {0x02, 0x96, 0xa8, 0x9b, 0xca, 0x78, 0x08, 0x41} \
+  }
+///
+/// The implementation of a Random Number Generator might be unsafe, when using
+/// a dummy implementation for instance. Allow identifying such implementation
+/// with this GUID.
+///
+#define EFI_RNG_ALGORITHM_UNSAFE \
+  { \
+    0x869f728c, 0x409d, 0x4ab4, {0xac, 0x03, 0x71, 0xd3, 0x09, 0xc1, 0xb3, 0xf4 } \
+  }
 
 /**
   Returns information about the random number generation implementation.
@@ -146,5 +164,7 @@ extern EFI_GUID  gEfiRngAlgorithmSp80090Ctr256Guid;
 extern EFI_GUID  gEfiRngAlgorithmX9313DesGuid;
 extern EFI_GUID  gEfiRngAlgorithmX931AesGuid;
 extern EFI_GUID  gEfiRngAlgorithmRaw;
+extern EFI_GUID  gEfiRngAlgorithmArmRndr;
+extern EFI_GUID  gEfiRngAlgorithmUnSafe;
 
 #endif
diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index 5b8477f4cb8f..959ca79d2664 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -643,6 +643,8 @@ [Guids]
   gEfiRngAlgorithmX9313DesGuid       = { 0x63c4785a, 0xca34, 0x4012, {0xa3, 0xc8, 0x0b, 0x6a, 0x32, 0x4f, 0x55, 0x46 }}
   gEfiRngAlgorithmX931AesGuid        = { 0xacd03321, 0x777e, 0x4d3d, {0xb1, 0xc8, 0x20, 0xcf, 0xd8, 0x88, 0x20, 0xc9 }}
   gEfiRngAlgorithmRaw                = { 0xe43176d7, 0xb6e8, 0x4827, {0xb7, 0x84, 0x7f, 0xfd, 0xc4, 0xb6, 0x85, 0x61 }}
+  gEfiRngAlgorithmArmRndr            = { 0x43d2fde3, 0x9d4e, 0x4d79, {0x02, 0x96, 0xa8, 0x9b, 0xca, 0x78, 0x08, 0x41 }}
+  gEfiRngAlgorithmUnSafe             = { 0x869f728c, 0x409d, 0x4ab4, {0xac, 0x03, 0x71, 0xd3, 0x09, 0xc1, 0xb3, 0xf4 }}
 
   ## Include/Protocol/AdapterInformation.h
   gEfiAdapterInfoMediaStateGuid       = { 0xD7C74207, 0xA831, 0x4A26, {0xB1, 0xF5, 0xD1, 0x93, 0x06, 0x5C, 0xE8, 0xB6 }}
-- 
2.25.1