[coreboot-gerrit] Patch set updated for coreboot: a276a93 amd/agesa/f16kb/Lib/amdlib.c: Integer overflow in loop construct

Edward O'Callaghan (eocallaghan@alterapraxis.com) gerrit at coreboot.org
Mon Dec 8 18:57:57 CET 2014


Edward O'Callaghan (eocallaghan at alterapraxis.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/7676

-gerrit

commit a276a930e123db0d488981c47cff5564d6f5ace9
Author: Edward O'Callaghan <eocallaghan at alterapraxis.com>
Date:   Sun Dec 7 05:20:14 2014 +1100

    amd/agesa/f16kb/Lib/amdlib.c: Integer overflow in loop construct
    
    As is the case in commit:
    
     3312ed7 amd/agesa/f1?/Lib/amdlib.c: Integer overflow in loop construct
    
    The semantics of this loop relies on an integer overflow in Index >=0
    that implies a return value of (UINT8)-1 which around wraps to 0xFF, or
    VOLT_UNSUPPORTED.
    
    Change-Id: Iced3eff3ae7b8935db3bdd6147372cf3b540883c
    Signed-off-by: Edward O'Callaghan <eocallaghan at alterapraxis.com>
---
 src/vendorcode/amd/agesa/f16kb/Lib/amdlib.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/vendorcode/amd/agesa/f16kb/Lib/amdlib.c b/src/vendorcode/amd/agesa/f16kb/Lib/amdlib.c
index d0e66b9..3a7ada8 100644
--- a/src/vendorcode/amd/agesa/f16kb/Lib/amdlib.c
+++ b/src/vendorcode/amd/agesa/f16kb/Lib/amdlib.c
@@ -360,11 +360,11 @@ LibAmdBitScanReverse (
   IN       UINT32 value
 )
 {
-  UINTN Index;
+  UINT8 Index;
   for (Index = 31; Index >= 0; Index--){
-      if (value & (1 << Index)) break;
+      if (value & (1 << Index)) return Index;
   }
-  return (UINT8) Index;
+  return 0xFF;
 }
 VOID
 LibAmdMsrRead (



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