File freerdp-CVE-2024-32660.patch of Package freerdp.34024

From 28e5db3ac410c5cf0f63a2f5a2d8f070f6b8cab8 Mon Sep 17 00:00:00 2001
From: akallabeth <akallabeth@posteo.net>
Date: Sat, 20 Apr 2024 19:59:48 +0200
Subject: [PATCH] [codec,zgfx] allocate in segment steps

do not trust the uncompressedSize of a ZGFX_SEGMENTED_MULTIPART and
allocate the output buffer in steps after decoding a segment.
---
 libfreerdp/codec/zgfx.c | 96 ++++++++++++++++++++++++++---------------
 1 file changed, 62 insertions(+), 34 deletions(-)

diff --git a/libfreerdp/codec/zgfx.c b/libfreerdp/codec/zgfx.c
index 28417e3e0..bf415cf0a 100644
--- a/libfreerdp/codec/zgfx.c
+++ b/libfreerdp/codec/zgfx.c
@@ -375,15 +375,56 @@ static BOOL zgfx_decompress_segment(ZGFX_CONTEXT* zgfx, wStream* stream, size_t
 	return TRUE;
 }
 
+/* Allocate the buffers a bit larger.
+ *
+ * Due to optimizations some h264 decoders will read data beyond
+ * the actual available data, so ensure that it will never be a
+ * out of bounds read.
+ */
+static BYTE* aligned_zgfx_malloc(size_t size)
+{
+	return malloc(size + 64);
+}
+
+static BOOL zgfx_append(ZGFX_CONTEXT* zgfx, BYTE** ppConcatenated, size_t uncompressedSize,
+                        size_t* pUsed)
+{
+	WINPR_ASSERT(zgfx);
+	WINPR_ASSERT(ppConcatenated);
+	WINPR_ASSERT(pUsed);
+
+	const size_t used = *pUsed;
+	if (zgfx->OutputCount > UINT32_MAX - used)
+		return FALSE;
+
+	if (used + zgfx->OutputCount > uncompressedSize)
+		return FALSE;
+
+	BYTE* tmp = realloc(*ppConcatenated, used + zgfx->OutputCount + 64ull);
+	if (!tmp)
+		return FALSE;
+	*ppConcatenated = tmp;
+	CopyMemory(&tmp[used], zgfx->OutputBuffer, zgfx->OutputCount);
+	*pUsed = used + zgfx->OutputCount;
+	return TRUE;
+}
+
 int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BYTE** ppDstData,
                     UINT32* pDstSize, UINT32 flags)
 {
 	int status = -1;
-	BYTE descriptor;
+	BYTE descriptor = 0;
+	size_t used = 0;
+	BYTE* pConcatenated = NULL;
 	wStream* stream = Stream_New((BYTE*)pSrcData, SrcSize);
 
 	WINPR_ASSERT(zgfx);
 	WINPR_ASSERT(stream);
+	WINPR_ASSERT(ppDstData);
+	WINPR_ASSERT(pDstSize);
+
+	*ppDstData = NULL;
+	*pDstSize = 0;
 
 	if (Stream_GetRemainingLength(stream) < 1)
 		goto fail;
@@ -395,25 +436,22 @@ int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BY
 		if (!zgfx_decompress_segment(zgfx, stream, Stream_GetRemainingLength(stream)))
 			goto fail;
 
-		*ppDstData = NULL;
-
 		if (zgfx->OutputCount > 0)
-			*ppDstData = (BYTE*)malloc(zgfx->OutputCount);
-
-		if (!*ppDstData)
-			goto fail;
-
-		*pDstSize = zgfx->OutputCount;
-		CopyMemory(*ppDstData, zgfx->OutputBuffer, zgfx->OutputCount);
+		{
+			if (!zgfx_append(zgfx, &pConcatenated, zgfx->OutputCount, &used))
+				goto fail;
+			if (used != zgfx->OutputCount)
+				goto fail;
+			*ppDstData = pConcatenated;
+			*pDstSize = zgfx->OutputCount;
+		}
 	}
 	else if (descriptor == ZGFX_SEGMENTED_MULTIPART)
 	{
-		UINT32 segmentSize;
-		UINT16 segmentNumber;
-		UINT16 segmentCount;
-		UINT32 uncompressedSize;
-		BYTE* pConcatenated;
-		size_t used = 0;
+		UINT32 segmentSize = 0;
+		UINT16 segmentNumber = 0;
+		UINT16 segmentCount = 0;
+		UINT32 uncompressedSize = 0;
 
 		if (Stream_GetRemainingLength(stream) < 6)
 			goto fail;
@@ -421,17 +459,6 @@ int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BY
 		Stream_Read_UINT16(stream, segmentCount);     /* segmentCount (2 bytes) */
 		Stream_Read_UINT32(stream, uncompressedSize); /* uncompressedSize (4 bytes) */
 
-		if (Stream_GetRemainingLength(stream) < segmentCount * sizeof(UINT32))
-			goto fail;
-
-		pConcatenated = (BYTE*)malloc(uncompressedSize);
-
-		if (!pConcatenated)
-			goto fail;
-
-		*ppDstData = pConcatenated;
-		*pDstSize = uncompressedSize;
-
 		for (segmentNumber = 0; segmentNumber < segmentCount; segmentNumber++)
 		{
 			if (Stream_GetRemainingLength(stream) < sizeof(UINT32))
@@ -442,16 +469,15 @@ int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BY
 			if (!zgfx_decompress_segment(zgfx, stream, segmentSize))
 				goto fail;
 
-			if (zgfx->OutputCount > UINT32_MAX - used)
+			if (!zgfx_append(zgfx, &pConcatenated, uncompressedSize, &used))
 				goto fail;
+		}
 
-			if (used + zgfx->OutputCount > uncompressedSize)
-				goto fail;
+		if (used != uncompressedSize)
+			goto fail;
 
-			CopyMemory(pConcatenated, zgfx->OutputBuffer, zgfx->OutputCount);
-			pConcatenated += zgfx->OutputCount;
-			used += zgfx->OutputCount;
-		}
+		*ppDstData = pConcatenated;
+		*pDstSize = uncompressedSize;
 	}
 	else
 	{
@@ -461,6 +487,8 @@ int zgfx_decompress(ZGFX_CONTEXT* zgfx, const BYTE* pSrcData, UINT32 SrcSize, BY
 	status = 1;
 fail:
 	Stream_Free(stream, FALSE);
+	if (status < 0)
+		free(pConcatenated);
 	return status;
 }
 
-- 
2.45.0