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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: edk2-devel@lists.01.org, michael.d.kinney@intel.com,
	liming.gao@intel.com
Cc: lersek@redhat.com, jaben.carsey@intel.com,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: [PATCH v3] MdePkg/BaseMemoryLib*: check for zero length in ZeroMem ()
Date: Fri,  4 Nov 2016 09:04:38 +0000	[thread overview]
Message-ID: <1478250278-27796-1-git-send-email-ard.biesheuvel@linaro.org> (raw)

Unlike other string functions in this library, ZeroMem () does not
return early when the length of the input buffer is 0. So add the
same to ZeroMem () as well, for all implementations of BaseMemoryLib
living under MdePkg/

This fixes an issue with the ARM implementation of BaseMemoryLibOPtDxe,
whose InternalMemZeroMem code does not expect a length of 0, and always
writes at least a single byte.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>
---
 MdePkg/Library/BaseMemoryLib/ZeroMemWrapper.c       | 6 +++++-
 MdePkg/Library/BaseMemoryLibMmx/ZeroMemWrapper.c    | 6 +++++-
 MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c | 6 +++++-
 MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c | 6 +++++-
 MdePkg/Library/BaseMemoryLibRepStr/ZeroMemWrapper.c | 6 +++++-
 MdePkg/Library/BaseMemoryLibSse2/ZeroMemWrapper.c   | 6 +++++-
 MdePkg/Library/PeiMemoryLib/ZeroMemWrapper.c        | 6 +++++-
 MdePkg/Library/UefiMemoryLib/ZeroMemWrapper.c       | 6 +++++-
 8 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/MdePkg/Library/BaseMemoryLib/ZeroMemWrapper.c b/MdePkg/Library/BaseMemoryLib/ZeroMemWrapper.c
index 2a0a038fd6c5..9dd0b45e188e 100644
--- a/MdePkg/Library/BaseMemoryLib/ZeroMemWrapper.c
+++ b/MdePkg/Library/BaseMemoryLib/ZeroMemWrapper.c
@@ -46,7 +46,11 @@ ZeroMem (
   IN UINTN  Length
   )
 {
-  ASSERT (!(Buffer == NULL && Length > 0));
+  if (Length == 0) {
+    return Buffer;
+  }
+
+  ASSERT (Buffer != NULL);
   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
   return InternalMemZeroMem (Buffer, Length);
 }
diff --git a/MdePkg/Library/BaseMemoryLibMmx/ZeroMemWrapper.c b/MdePkg/Library/BaseMemoryLibMmx/ZeroMemWrapper.c
index 2a0a038fd6c5..9dd0b45e188e 100644
--- a/MdePkg/Library/BaseMemoryLibMmx/ZeroMemWrapper.c
+++ b/MdePkg/Library/BaseMemoryLibMmx/ZeroMemWrapper.c
@@ -46,7 +46,11 @@ ZeroMem (
   IN UINTN  Length
   )
 {
-  ASSERT (!(Buffer == NULL && Length > 0));
+  if (Length == 0) {
+    return Buffer;
+  }
+
+  ASSERT (Buffer != NULL);
   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
   return InternalMemZeroMem (Buffer, Length);
 }
diff --git a/MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c b/MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c
index 2a0a038fd6c5..9dd0b45e188e 100644
--- a/MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c
+++ b/MdePkg/Library/BaseMemoryLibOptDxe/ZeroMemWrapper.c
@@ -46,7 +46,11 @@ ZeroMem (
   IN UINTN  Length
   )
 {
-  ASSERT (!(Buffer == NULL && Length > 0));
+  if (Length == 0) {
+    return Buffer;
+  }
+
+  ASSERT (Buffer != NULL);
   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
   return InternalMemZeroMem (Buffer, Length);
 }
diff --git a/MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c b/MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c
index 2a0a038fd6c5..9dd0b45e188e 100644
--- a/MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c
+++ b/MdePkg/Library/BaseMemoryLibOptPei/ZeroMemWrapper.c
@@ -46,7 +46,11 @@ ZeroMem (
   IN UINTN  Length
   )
 {
-  ASSERT (!(Buffer == NULL && Length > 0));
+  if (Length == 0) {
+    return Buffer;
+  }
+
+  ASSERT (Buffer != NULL);
   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
   return InternalMemZeroMem (Buffer, Length);
 }
diff --git a/MdePkg/Library/BaseMemoryLibRepStr/ZeroMemWrapper.c b/MdePkg/Library/BaseMemoryLibRepStr/ZeroMemWrapper.c
index 2a0a038fd6c5..9dd0b45e188e 100644
--- a/MdePkg/Library/BaseMemoryLibRepStr/ZeroMemWrapper.c
+++ b/MdePkg/Library/BaseMemoryLibRepStr/ZeroMemWrapper.c
@@ -46,7 +46,11 @@ ZeroMem (
   IN UINTN  Length
   )
 {
-  ASSERT (!(Buffer == NULL && Length > 0));
+  if (Length == 0) {
+    return Buffer;
+  }
+
+  ASSERT (Buffer != NULL);
   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
   return InternalMemZeroMem (Buffer, Length);
 }
diff --git a/MdePkg/Library/BaseMemoryLibSse2/ZeroMemWrapper.c b/MdePkg/Library/BaseMemoryLibSse2/ZeroMemWrapper.c
index 2a0a038fd6c5..9dd0b45e188e 100644
--- a/MdePkg/Library/BaseMemoryLibSse2/ZeroMemWrapper.c
+++ b/MdePkg/Library/BaseMemoryLibSse2/ZeroMemWrapper.c
@@ -46,7 +46,11 @@ ZeroMem (
   IN UINTN  Length
   )
 {
-  ASSERT (!(Buffer == NULL && Length > 0));
+  if (Length == 0) {
+    return Buffer;
+  }
+
+  ASSERT (Buffer != NULL);
   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
   return InternalMemZeroMem (Buffer, Length);
 }
diff --git a/MdePkg/Library/PeiMemoryLib/ZeroMemWrapper.c b/MdePkg/Library/PeiMemoryLib/ZeroMemWrapper.c
index 5adddbbfad66..a3aa7d10a689 100644
--- a/MdePkg/Library/PeiMemoryLib/ZeroMemWrapper.c
+++ b/MdePkg/Library/PeiMemoryLib/ZeroMemWrapper.c
@@ -46,7 +46,11 @@ ZeroMem (
   IN UINTN  Length
   )
 {
-  ASSERT (!(Buffer == NULL && Length > 0));
+  if (Length == 0) {
+    return Buffer;
+  }
+
+  ASSERT (Buffer != NULL);
   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
   return InternalMemZeroMem (Buffer, Length);
 }
diff --git a/MdePkg/Library/UefiMemoryLib/ZeroMemWrapper.c b/MdePkg/Library/UefiMemoryLib/ZeroMemWrapper.c
index 5adddbbfad66..a3aa7d10a689 100644
--- a/MdePkg/Library/UefiMemoryLib/ZeroMemWrapper.c
+++ b/MdePkg/Library/UefiMemoryLib/ZeroMemWrapper.c
@@ -46,7 +46,11 @@ ZeroMem (
   IN UINTN  Length
   )
 {
-  ASSERT (!(Buffer == NULL && Length > 0));
+  if (Length == 0) {
+    return Buffer;
+  }
+
+  ASSERT (Buffer != NULL);
   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
   return InternalMemZeroMem (Buffer, Length);
 }
-- 
2.7.4



             reply	other threads:[~2016-11-04  9:04 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-04  9:04 Ard Biesheuvel [this message]
2016-11-04  9:08 ` [PATCH v3] MdePkg/BaseMemoryLib*: check for zero length in ZeroMem () Gao, Liming
2016-11-04  9:54   ` Ard Biesheuvel

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