[v2] MdePkg/UefiFileHandleLib: Fix potential NULL dereference.

[edk2] [PATCH v2] MdePkg/UefiFileHandleLib: Fix potential NULL dereference.

Marvin Häuser posted 1 patch 5 years, 11 months ago

Diff against v1
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MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c | 28 +++++++++++---------
1 file changed, 15 insertions(+), 13 deletions(-)

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[edk2] [PATCH v2] MdePkg/UefiFileHandleLib: Fix potential NULL dereference.

Posted by Marvin Häuser 5 years, 11 months ago

Move the NULL-check in FileHandleGetInfo() to directly after the
allocation to prevent potential NULL dereferences.

V2:
  - Do not change the copyright date as requested.
  - Added R-bs from V1 as no functional changes have been made.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marvin Haeuser <Marvin.Haeuser@outlook.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
---
 MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c | 28 +++++++++++---------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c b/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
index 57aad77bc135..5b3d39ef6103 100644
--- a/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
+++ b/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c
@@ -74,19 +74,21 @@ FileHandleGetInfo (
     // error is expected.  getting size to allocate
     //
     FileInfo = AllocateZeroPool(FileInfoSize);
-    //
-    // now get the information
-    //
-    Status = FileHandle->GetInfo(FileHandle,
-                                 &gEfiFileInfoGuid,
-                                 &FileInfoSize,
-                                 FileInfo);
-    //
-    // if we got an error free the memory and return NULL
-    //
-    if (EFI_ERROR(Status) && (FileInfo != NULL)) {
-      FreePool(FileInfo);
-      FileInfo = NULL;
+    if (FileInfo != NULL) {
+      //
+      // now get the information
+      //
+      Status = FileHandle->GetInfo(FileHandle,
+                                   &gEfiFileInfoGuid,
+                                   &FileInfoSize,
+                                   FileInfo);
+      //
+      // if we got an error free the memory and return NULL
+      //
+      if (EFI_ERROR(Status)) {
+        FreePool(FileInfo);
+        FileInfo = NULL;
+      }
     }
   }
   return (FileInfo);
-- 
2.17.0.windows.1

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