[edk2] [Patch 1/2] BaseTools/GenFw: Exit with error when header lookup fails

[Yonghong Zhu]

This patch revises GetPhdrByIndex and GetShdrByIndex to cause GenFw to
exit with an error message when a section header lookup fails.  The
current behavior of those functions in such circumstances is to return
NULL, which can cause GenFw to subsequently fault when it attempts to
dereference the null pointer.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael LeMay <michael.le...@intel.com>
Reviewed-by: Yonghong Zhu <yonghong....@intel.com>
---
 BaseTools/Source/C/GenFw/Elf32Convert.c | 10 +++++++---
 BaseTools/Source/C/GenFw/Elf64Convert.c |  7 +++++--
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/BaseTools/Source/C/GenFw/Elf32Convert.c 
b/BaseTools/Source/C/GenFw/Elf32Convert.c
index eede645..dfd8bec 100644
--- a/BaseTools/Source/C/GenFw/Elf32Convert.c
+++ b/BaseTools/Source/C/GenFw/Elf32Convert.c
@@ -189,23 +189,27 @@ STATIC
 Elf_Shdr*
 GetShdrByIndex (
   UINT32 Num
   )
 {
-  if (Num >= mEhdr->e_shnum)
-    return NULL;
+  if (Num >= mEhdr->e_shnum) {
+    Error (NULL, 0, 3000, "Invalid", "GetShdrByIndex: Index %u is too high.", 
Num);
+    exit(EXIT_FAILURE);
+  }
+
   return (Elf_Shdr*)((UINT8*)mShdrBase + Num * mEhdr->e_shentsize);
 }
 
 STATIC
 Elf_Phdr*
 GetPhdrByIndex (
   UINT32 num
   )
 {
   if (num >= mEhdr->e_phnum) {
-    return NULL;
+    Error (NULL, 0, 3000, "Invalid", "GetPhdrByIndex: Index %u is too high.", 
num);
+    exit(EXIT_FAILURE);
   }
 
   return (Elf_Phdr *)((UINT8*)mPhdrBase + num * mEhdr->e_phentsize);
 }
 
diff --git a/BaseTools/Source/C/GenFw/Elf64Convert.c 
b/BaseTools/Source/C/GenFw/Elf64Convert.c
index 90d80a2..3b55afa 100644
--- a/BaseTools/Source/C/GenFw/Elf64Convert.c
+++ b/BaseTools/Source/C/GenFw/Elf64Convert.c
@@ -195,12 +195,15 @@ STATIC
 Elf_Shdr*
 GetShdrByIndex (
   UINT32 Num
   )
 {
-  if (Num >= mEhdr->e_shnum)
-    return NULL;
+  if (Num >= mEhdr->e_shnum) {
+    Error (NULL, 0, 3000, "Invalid", "GetShdrByIndex: Index %u is too high.", 
Num);
+    exit(EXIT_FAILURE);
+  }
+
   return (Elf_Shdr*)((UINT8*)mShdrBase + Num * mEhdr->e_shentsize);
 }
 
 STATIC
 UINT32
-- 
2.6.1.windows.1

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