[PATCH] drivers/staging/bcm: Integer overflow

[Wenliang Fan]

The checking condition in 'validateFlash2xReadWrite()' is not
sufficient. A large number invalid would cause an integer overflow and
pass the condition, which could cause further integer overflows in
'Bcmchar.c:bcm_char_ioctl()'.

Signed-off-by: Wenliang Fan <fanwlexca@xxxxxxxxx>
---
 drivers/staging/bcm/nvm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/staging/bcm/nvm.c b/drivers/staging/bcm/nvm.c
index 9e5f955..7f3dd4b 100644
--- a/drivers/staging/bcm/nvm.c
+++ b/drivers/staging/bcm/nvm.c
@@ -3944,6 +3944,11 @@ int validateFlash2xReadWrite(struct bcm_mini_adapter *Adapter, struct bcm_flash2
 
 	BCM_DEBUG_PRINT(Adapter, DBG_TYPE_OTHERS, NVM_RW, DBG_LVL_ALL, "End offset :%x\n", uiSectEndOffset);
 
+	/* psFlash2xReadWrite->offset and uiNumOfBytes are user controlled and can lead to integer overflows */
+	if (uiSectStartOffset + psFlash2xReadWrite->offset < uiSectStartOffset)
+		return false;
+	if (uiSectStartOffset + psFlash2xReadWrite->offset + uiNumOfBytes < uiNumOfBytes)
+		return false;
 	/* Checking the boundary condition */
 	if ((uiSectStartOffset + psFlash2xReadWrite->offset + uiNumOfBytes) <= uiSectEndOffset)
 		return TRUE;
-- 
1.8.5.rc1.28.g7061504

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