Protect against out of bounds memory type, replaces !3598

SPDAccessor/SPDAccessor.cpp

@@ -66,7 +66,8 @@ const char *spd_memory_type_name[] =
     "LPDDR4",
     "LPDDR4X",
     "DDR5",
-    "LPDDR5"
+    "LPDDR5",
+    "Unknown"
 };
 
 SPDAccessor::SPDAccessor(i2c_smbus_interface *bus, uint8_t spd_addr)
@@ -161,7 +162,16 @@ DDR4Accessor::~DDR4Accessor()
 
 SPDMemoryType DDR4Accessor::memory_type()
 {
-    return((SPDMemoryType)(this->at(BASIC_MEMORY_TYPE_ADDR)));
+    SPDMemoryType type = (SPDMemoryType)(this->at(BASIC_MEMORY_TYPE_ADDR));
+
+    if(type <= SPD_UNKNOWN)
+    {
+        return(type);
+    }
+    else
+    {
+        return(SPD_UNKNOWN);
+    }
 }
 
 uint16_t DDR4Accessor::jedec_id()
@@ -195,7 +205,16 @@ DDR5Accessor::~DDR5Accessor()
 
 SPDMemoryType DDR5Accessor::memory_type()
 {
-    return((SPDMemoryType)(this->at(BASIC_MEMORY_TYPE_ADDR)));
+    SPDMemoryType type = (SPDMemoryType)(this->at(BASIC_MEMORY_TYPE_ADDR));
+
+    if(type <= SPD_UNKNOWN)
+    {
+        return(type);
+    }
+    else
+    {
+        return(SPD_UNKNOWN);
+    }
 }
 
 uint16_t DDR5Accessor::jedec_id()

SPDAccessor/SPDCommon.h

@@ -48,7 +48,8 @@ typedef enum
     SPD_LPDDR4_SDRAM  = 16,
     SPD_LPDDR4X_SDRAM = 17,
     SPD_DDR5_SDRAM    = 18,
-    SPD_LPDDR5_SDRAM  = 19
+    SPD_LPDDR5_SDRAM  = 19,
+    SPD_UNKNOWN       = 20,
 } SPDMemoryType;
 
 #define SPD_IO_DELAY   1ms

SPDAccessor/SPDDetector.cpp

@@ -30,7 +30,14 @@ bool SPDDetector::is_valid() const
 
 SPDMemoryType SPDDetector::memory_type() const
 {
-    return(mem_type);
+    if(mem_type <= SPD_UNKNOWN)
+    {
+        return(mem_type);
+    }
+    else
+    {
+        return(SPD_UNKNOWN);
+    }
 }
 
 void SPDDetector::detect_memory_type()

SPDAccessor/SPDWrapper.cpp

@@ -65,7 +65,14 @@ SPDWrapper::~SPDWrapper()
 
 SPDMemoryType SPDWrapper::memory_type()
 {
-    return mem_type;
+    if(mem_type <= SPD_UNKNOWN)
+    {
+        return(mem_type);
+    }
+    else
+    {
+        return(SPD_UNKNOWN);
+    }
 }
 
 uint8_t SPDWrapper::address()