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From: "Ard Biesheuvel" <ard.biesheuvel@arm.com>
To: devel@edk2.groups.io
Cc: leif@nuviainc.com, pete@akeo.ie, awarkentin@vmware.com,
	jeremy.linton@arm.com, Samer.El-Haj-Mahmoud@arm.com,
	Ard Biesheuvel <ard.biesheuvel@arm.com>
Subject: [PATCH] EmbeddedPkg/NonCoherentDmaLib: avoid dereferencing bogus buffer address
Date: Wed, 17 Jun 2020 17:38:24 +0200	[thread overview]
Message-ID: <20200617153824.1175136-1-ard.biesheuvel@arm.com> (raw)

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@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


             reply	other threads:[~2020-06-17 15:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-17 15:38 Ard Biesheuvel [this message]
2020-06-17 16:14 ` [PATCH] EmbeddedPkg/NonCoherentDmaLib: avoid dereferencing bogus buffer address Leif Lindholm
2020-06-17 18:31   ` Ard Biesheuvel
2020-06-17 16:19 ` [edk2-devel] " Andrei Warkentin

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