[edk2-devel] [PATCH] EmbeddedPkg/NonCoherentDmaLib: avoid dereferencing bogus buffer address

[Ard Biesheuvel]

The bounce buffering code in NonCoherentDmaLib copies data into the
bounce buffer using CopyMem(), but passes Map->HostAddress as the
source of the copy before it has been assigned its correct value.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel at arm.com>
---
 EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c b/EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c
index 115345765435..9c8ef5bfb533 100644
--- a/EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c
+++ b/EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.c
@@ -225,8 +225,7 @@ DmaMap (
     }
 
     if (Map->Operation == MapOperationBusMasterRead) {
-      CopyMem (Map->BufferAddress, (VOID *)(UINTN)Map->HostAddress,
-        *NumberOfBytes);
+      CopyMem (Map->BufferAddress, (VOID *)(UINTN)HostAddress, *NumberOfBytes);
     }
     mCpu->FlushDataCache (mCpu, (UINTN)Map->BufferAddress, AllocSize,
             EfiCpuFlushTypeWriteBack);
-- 
2.27.0


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