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| author | Long Qin <qin.long@intel.com> | 2017-11-01 16:10:04 +0800 |
|---|---|---|
| committer | Long Qin <qin.long@intel.com> | 2017-11-06 14:50:17 +0800 |
| commit | cf8197a39d07179027455421a182598bd6989999 (patch) | |
| tree | e84e54f0e272db3bcac08d4de9c3f008e734b718 /CryptoPkg | |
| parent | f6f486e7bf7667ca7bcf50d808e056bd5ac7deaf (diff) | |
| download | edk2-cf8197a39d07179027455421a182598bd6989999.tar.gz edk2-cf8197a39d07179027455421a182598bd6989999.tar.bz2 edk2-cf8197a39d07179027455421a182598bd6989999.zip | |
CryptoPkg/BaseCryptLib: Fix buffer overflow issue in realloc wrapper
There is one long-standing problem in CRT realloc wrapper, which will
cause the obvious buffer overflow issue when re-allocating one bigger
memory block:
void *realloc (void *ptr, size_t size)
{
//
// BUG: hardcode OldSize == size! We have no any knowledge about
// memory size of original pointer ptr.
//
return ReallocatePool ((UINTN) size, (UINTN) size, ptr);
}
This patch introduces one extra header to record the memory buffer size
information when allocating memory block from malloc routine, and re-wrap
the realloc() and free() routines to remove this BUG.
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ting Ye <ting.ye@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Qin Long <qin.long@intel.com>
Reviewed-by: Jian J Wang <jian.j.wang@intel.com>
Validated-by: Jian J Wang <jian.j.wang@intel.com>
Diffstat (limited to 'CryptoPkg')
| -rw-r--r-- | CryptoPkg/Library/BaseCryptLib/SysCall/BaseMemAllocation.c | 83 |
1 files changed, 76 insertions, 7 deletions
diff --git a/CryptoPkg/Library/BaseCryptLib/SysCall/BaseMemAllocation.c b/CryptoPkg/Library/BaseCryptLib/SysCall/BaseMemAllocation.c index f390e0d449..19c071e2bf 100644 --- a/CryptoPkg/Library/BaseCryptLib/SysCall/BaseMemAllocation.c +++ b/CryptoPkg/Library/BaseCryptLib/SysCall/BaseMemAllocation.c @@ -17,33 +17,102 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. #include <Library/MemoryAllocationLib.h>
//
+// Extra header to record the memory buffer size from malloc routine.
+//
+#define CRYPTMEM_HEAD_SIGNATURE SIGNATURE_32('c','m','h','d')
+typedef struct {
+ UINT32 Signature;
+ UINT32 Reserved;
+ UINTN Size;
+} CRYPTMEM_HEAD;
+
+#define CRYPTMEM_OVERHEAD sizeof(CRYPTMEM_HEAD)
+
+//
// -- Memory-Allocation Routines --
//
/* Allocates memory blocks */
void *malloc (size_t size)
{
- return AllocatePool ((UINTN) size);
+ CRYPTMEM_HEAD *PoolHdr;
+ UINTN NewSize;
+ VOID *Data;
+
+ //
+ // Adjust the size by the buffer header overhead
+ //
+ NewSize = (UINTN)(size) + CRYPTMEM_OVERHEAD;
+
+ Data = AllocatePool (NewSize);
+ if (Data != NULL) {
+ PoolHdr = (CRYPTMEM_HEAD *)Data;
+ //
+ // Record the memory brief information
+ //
+ PoolHdr->Signature = CRYPTMEM_HEAD_SIGNATURE;
+ PoolHdr->Size = size;
+
+ return (VOID *)(PoolHdr + 1);
+ } else {
+ //
+ // The buffer allocation failed.
+ //
+ return NULL;
+ }
}
/* Reallocate memory blocks */
void *realloc (void *ptr, size_t size)
{
- //
- // BUG: hardcode OldSize == size! We have no any knowledge about
- // memory size of original pointer ptr.
- //
- return ReallocatePool ((UINTN) size, (UINTN) size, ptr);
+ CRYPTMEM_HEAD *OldPoolHdr;
+ CRYPTMEM_HEAD *NewPoolHdr;
+ UINTN OldSize;
+ UINTN NewSize;
+ VOID *Data;
+
+ NewSize = (UINTN)size + CRYPTMEM_OVERHEAD;
+ Data = AllocatePool (NewSize);
+ if (Data != NULL) {
+ NewPoolHdr = (CRYPTMEM_HEAD *)Data;
+ NewPoolHdr->Signature = CRYPTMEM_HEAD_SIGNATURE;
+ NewPoolHdr->Size = size;
+ if (ptr != NULL) {
+ //
+ // Retrieve the original size from the buffer header.
+ //
+ OldPoolHdr = (CRYPTMEM_HEAD *)ptr - 1;
+ ASSERT (OldPoolHdr->Signature == CRYPTMEM_HEAD_SIGNATURE);
+ OldSize = OldPoolHdr->Size;
+
+ //
+ // Duplicate the buffer content.
+ //
+ CopyMem ((VOID *)(NewPoolHdr + 1), ptr, MIN (OldSize, size));
+ FreePool ((VOID *)OldPoolHdr);
+ }
+
+ return (VOID *)(NewPoolHdr + 1);
+ } else {
+ //
+ // The buffer allocation failed.
+ //
+ return NULL;
+ }
}
/* De-allocates or frees a memory block */
void free (void *ptr)
{
+ CRYPTMEM_HEAD *PoolHdr;
+
//
// In Standard C, free() handles a null pointer argument transparently. This
// is not true of FreePool() below, so protect it.
//
if (ptr != NULL) {
- FreePool (ptr);
+ PoolHdr = (CRYPTMEM_HEAD *)ptr - 1;
+ ASSERT (PoolHdr->Signature == CRYPTMEM_HEAD_SIGNATURE);
+ FreePool (PoolHdr);
}
}
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