[edk2-platforms][PATCH v4 01/12] Ext4Pkg: Fix memory leak in Ext4RetrieveDirent

["Savva Mitrofanov" <savvamtr@gmail.com>]

We need to free buffer on return if BlockRemainder != 0. Also changed
return logic from function to use use common exit to prevent code
duplication.

Cc: Marvin Häuser <mhaeuser@posteo.de>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vitaly Cheptsov <vit9696@protonmail.com>
Fixes: d9ceedca6c8f ("Ext4Pkg: Add Ext4Dxe driver.")
Signed-off-by: Savva Mitrofanov <savvamtr@gmail.com>
Reviewed-by: Pedro Falcato <pedro.falcato@gmail.com>
Reviewed-by: Marvin Häuser <mhaeuser@posteo.de>
---
 Features/Ext4Pkg/Ext4Dxe/Directory.c | 30 +++++++++++---------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/Features/Ext4Pkg/Ext4Dxe/Directory.c b/Features/Ext4Pkg/Ext4Dxe/Directory.c
index 73d21d9f9542..c7992cc72717 100644
--- a/Features/Ext4Pkg/Ext4Dxe/Directory.c
+++ b/Features/Ext4Pkg/Ext4Dxe/Directory.c
@@ -113,8 +113,7 @@ Ext4RetrieveDirent (
   UINTN           ToCopy;
   UINTN           BlockOffset;
 
-  Status = EFI_NOT_FOUND;
-  Buf    = AllocatePool (Partition->BlockSize);
+  Buf = AllocatePool (Partition->BlockSize);
 
   if (Buf == NULL) {
     return EFI_OUT_OF_RESOURCES;
@@ -128,7 +127,8 @@ Ext4RetrieveDirent (
   DivU64x32Remainder (DirInoSize, Partition->BlockSize, &BlockRemainder);
   if (BlockRemainder != 0) {
     // Directory inodes need to have block aligned sizes
-    return EFI_VOLUME_CORRUPTED;
+    Status = EFI_VOLUME_CORRUPTED;
+    goto Out;
   }
 
   while (Off < DirInoSize) {
@@ -137,8 +137,7 @@ Ext4RetrieveDirent (
     Status = Ext4Read (Partition, Directory, Buf, Off, &Length);
 
     if (Status != EFI_SUCCESS) {
-      FreePool (Buf);
-      return Status;
+      goto Out;
     }
 
     for (BlockOffset = 0; BlockOffset < Partition->BlockSize; ) {
@@ -146,19 +145,19 @@ Ext4RetrieveDirent (
       RemainingBlock = Partition->BlockSize - BlockOffset;
       // Check if the minimum directory entry fits inside [BlockOffset, EndOfBlock]
       if (RemainingBlock < EXT4_MIN_DIR_ENTRY_LEN) {
-        FreePool (Buf);
-        return EFI_VOLUME_CORRUPTED;
+        Status = EFI_VOLUME_CORRUPTED;
+        goto Out;
       }
 
       if (!Ext4ValidDirent (Entry)) {
-        FreePool (Buf);
-        return EFI_VOLUME_CORRUPTED;
+        Status = EFI_VOLUME_CORRUPTED;
+        goto Out;
       }
 
       if ((Entry->name_len > RemainingBlock) || (Entry->rec_len > RemainingBlock)) {
         // Corrupted filesystem
-        FreePool (Buf);
-        return EFI_VOLUME_CORRUPTED;
+        Status = EFI_VOLUME_CORRUPTED;
+        goto Out;
       }
 
       // Unused entry
@@ -193,8 +192,8 @@ Ext4RetrieveDirent (
         ToCopy = MIN (Entry->rec_len, sizeof (EXT4_DIR_ENTRY));
 
         CopyMem (Result, Entry, ToCopy);
-        FreePool (Buf);
-        return EFI_SUCCESS;
+        Status = EFI_SUCCESS;
+        goto Out;
       }
 
       BlockOffset += Entry->rec_len;
@@ -203,8 +202,11 @@ Ext4RetrieveDirent (
     Off += Partition->BlockSize;
   }
 
+  Status = EFI_NOT_FOUND;
+
+Out:
   FreePool (Buf);
-  return EFI_NOT_FOUND;
+  return Status;
 }
 
 /**
-- 
2.39.1