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* [PATCH v3] MdePkg/BaseMemoryLib*: check for zero length in ZeroMem ()
@ 2016-11-04  9:04 Ard Biesheuvel
  2016-11-04  9:08 ` Gao, Liming
  0 siblings, 1 reply; 3+ messages in thread
From: Ard Biesheuvel @ 2016-11-04  9:04 UTC (permalink / raw)
  To: edk2-devel, michael.d.kinney, liming.gao
  Cc: lersek, jaben.carsey, Ard Biesheuvel

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



^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2016-11-04  9:54 UTC | newest]

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

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