From 10d38d08079e6262da9cb43559b00968ebb080ec Mon Sep 17 00:00:00 2001
From: dragonmux <git@dragonmux.network>
Date: Thu, 7 Dec 2023 10:44:02 +0000
Subject: [PATCH] sfdp: Implemented a validation step for the SFDP Basic
 Parameter Table Header

---
 src/include/sfdpInternal.hxx |  3 ++-
 src/sfdp.cxx                 | 47 ++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/src/include/sfdpInternal.hxx b/src/include/sfdpInternal.hxx
index 80fba09..b1a5d89 100644
--- a/src/include/sfdpInternal.hxx
+++ b/src/include/sfdpInternal.hxx
@@ -63,7 +63,8 @@ namespace bmpflash::sfdp
 
 		[[nodiscard]] uint16_t jedecParameterID() const noexcept
 			{ return static_cast<uint16_t>((jedecParameterIDHigh << 8U) | jedecParameterIDLow); }
-		[[nodiscard]] size_t tableLength() const noexcept { return static_cast<size_t>(tableLengthInU32s) * 4U; }
+		[[nodiscard]] size_t tableLength() const noexcept { return static_cast<size_t>(tableLengthInU32s * 4U); }
+		void validate() noexcept;
 	};
 
 	struct memoryDensity_t
diff --git a/src/sfdp.cxx b/src/sfdp.cxx
index 86edbc7..b1e701f 100644
--- a/src/sfdp.cxx
+++ b/src/sfdp.cxx
@@ -111,6 +111,7 @@ namespace bmpflash::sfdp
 			displayTableHeader(tableHeader, idx + 1U);
 			if (tableHeader.jedecParameterID() == basicSPIParameterTable)
 			{
+				tableHeader.validate();
 				if (!displayBasicParameterTable(probe, tableHeader))
 					return false;
 			}
@@ -185,7 +186,10 @@ namespace bmpflash::sfdp
 				return std::nullopt;
 
 			if (tableHeader.jedecParameterID() == basicSPIParameterTable)
+			{
+				tableHeader.validate();
 				return readBasicParameterTable(probe, tableHeader);
+			}
 		}
 		return std::nullopt;
 	}
@@ -226,4 +230,47 @@ namespace bmpflash::sfdp
 				return tableLength();
 		}
 	}
+
+	void parameterTableHeader_t::validate() noexcept
+	{
+		const auto expectedLength{lengthForVersion()};
+		const auto actualLength{tableLength()};
+		// If the table is the proper length for the version, we're done
+		if (actualLength == expectedLength)
+			return;
+
+		// If the table is longer than it should be for the stated version, truncate it
+		if (actualLength > expectedLength)
+			tableLengthInU32s = static_cast<uint8_t>(expectedLength / 4U);
+		// Otherwise fix the version number to match the one for the actual length
+		else
+		{
+			// 24 uint32_t's -> v1.8
+			if (expectedLength == 96U)
+			{
+				versionMajor = 1U;
+				versionMinor = 8U;
+			}
+			// 21 uint32_t's -> v1.7
+			else if (expectedLength == 84U)
+			{
+				versionMajor = 1U;
+				versionMinor = 7U;
+			}
+			// 16 uint32_t's -> v1.6 (assume the newer standard)
+			else if (expectedLength == 64U)
+			{
+				versionMajor = 1U;
+				versionMinor = 6U;
+			}
+			// 21 uint32_t's -> v1.4 (assume the newer standard)
+			else if (expectedLength == 9U)
+			{
+				versionMajor = 1U;
+				versionMinor = 4U;
+			}
+			else
+				console.error("This should not be possible, please check sfdp.cxx for sanity");
+		}
+	}
 } // namespace bmpflash::sfdp