From f42eaf4680da0b0684ec1b9d64b7e417f8ff8160 Mon Sep 17 00:00:00 2001
From: "Yang, Longlong" <longlong.yang@intel.com>
Date: Tue, 23 Jan 2024 01:37:22 -0500
Subject: [PATCH] ignore unknown versions in version response.

Current design will reject version response if there is a
version other than 0x10, 0x11 and 0x12. In this patch,
will not reject such version response, instead, unknown
versions will be ignored.

Signed-off-by: Yang, Longlong <longlong.yang@intel.com>
---
 spdmlib/src/common/mod.rs      |  2 +-
 spdmlib/src/message/version.rs | 34 +++++++++++++++++++++++++---------
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/spdmlib/src/common/mod.rs b/spdmlib/src/common/mod.rs
index 760f94d..fba4cdc 100644
--- a/spdmlib/src/common/mod.rs
+++ b/spdmlib/src/common/mod.rs
@@ -1151,7 +1151,7 @@ pub struct SpdmNegotiateInfo {
     pub rsp_max_spdm_msg_size_sel: u32, // spdm 1.2
 }
 
-pub const MAX_MANAGED_BUFFER_A_SIZE: usize = 150 + 2 * MAX_SPDM_VERSION_COUNT;
+pub const MAX_MANAGED_BUFFER_A_SIZE: usize = 150 + 2 * 255; // for version response, there can be more than MAX_SPDM_VERSION_COUNT versions.
 pub const MAX_MANAGED_BUFFER_B_SIZE: usize =
     24 + SPDM_MAX_HASH_SIZE * SPDM_MAX_SLOT_NUMBER + config::MAX_SPDM_CERT_CHAIN_DATA_SIZE;
 pub const MAX_MANAGED_BUFFER_C_SIZE: usize =
diff --git a/spdmlib/src/message/version.rs b/spdmlib/src/message/version.rs
index 4f6621d..2c2c4ef 100644
--- a/spdmlib/src/message/version.rs
+++ b/spdmlib/src/message/version.rs
@@ -95,9 +95,7 @@ impl SpdmCodec for SpdmVersionResponsePayload {
         u8::read(r)?; // reserved
         let version_number_entry_count = u8::read(r)?;
 
-        if version_number_entry_count < 1
-            || version_number_entry_count > MAX_SPDM_VERSION_COUNT as u8
-        {
+        if version_number_entry_count == 0 {
             return None;
         }
 
@@ -108,14 +106,32 @@ impl SpdmCodec for SpdmVersionResponsePayload {
             },
             MAX_SPDM_VERSION_COUNT,
         );
-        for version in versions
-            .iter_mut()
-            .take(version_number_entry_count as usize)
-        {
-            *version = SpdmVersionStruct::read(r)?;
+
+        let mut version_count = 0;
+        let rest = r.take(version_number_entry_count as usize * 2)?;
+
+        for i in 0..version_number_entry_count {
+            if let Some(ver) = SpdmVersionStruct::read_bytes(&rest[i as usize * 2..]) {
+                if version_count < MAX_SPDM_VERSION_COUNT {
+                    versions[version_count] = ver;
+                    version_count += 1;
+                } else {
+                    // the buffer is full now, stop for scaning more versions
+                    break;
+                }
+            } else {
+                // for unknown versions,
+                if rest[i as usize * 2 + 1] < 0x10 {
+                    // find a version which is lower than the 0x10 version
+                    return None;
+                } else {
+                    // for any other version, just ignore it
+                }
+            }
         }
+
         Some(SpdmVersionResponsePayload {
-            version_number_entry_count,
+            version_number_entry_count: version_count as u8,
             versions,
         })
     }