From e725a66c0202b5f36c2f9d59d26a65c53bbf21f7 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 14 Mar 2016 15:18:35 +0100 Subject: [PATCH] farsync: fix off-by-one bug in fst_add_one gcc-6 finds an out of bounds access in the fst_add_one function when calculating the end of the mmio area: drivers/net/wan/farsync.c: In function 'fst_add_one': drivers/net/wan/farsync.c:418:53: error: index 2 denotes an offset greater than size of 'u8[2][8192] {aka unsigned char[2][8192]}' [-Werror=array-bounds] #define BUF_OFFSET(X) (BFM_BASE + offsetof(struct buf_window, X)) ^ include/linux/compiler-gcc.h:158:21: note: in definition of macro '__compiler_offsetof' __builtin_offsetof(a, b) ^ drivers/net/wan/farsync.c:418:37: note: in expansion of macro 'offsetof' #define BUF_OFFSET(X) (BFM_BASE + offsetof(struct buf_window, X)) ^~~~~~~~ drivers/net/wan/farsync.c:2519:36: note: in expansion of macro 'BUF_OFFSET' + BUF_OFFSET ( txBuffer[i][NUM_TX_BUFFER][0]); ^~~~~~~~~~ The warning is correct, but not critical because this appears to be a write-only variable that is set by each WAN driver but never accessed afterwards. I'm taking the minimal fix here, using the correct pointer by pointing 'mem_end' to the last byte inside of the register area as all other WAN drivers do, rather than the first byte outside of it. An alternative would be to just remove the mem_end member entirely. Signed-off-by: Arnd Bergmann Signed-off-by: David S. Miller --- drivers/net/wan/farsync.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wan/farsync.c b/drivers/net/wan/farsync.c index 44541dbc5c28..69b994f3b8c5 100644 --- a/drivers/net/wan/farsync.c +++ b/drivers/net/wan/farsync.c @@ -2516,7 +2516,7 @@ fst_add_one(struct pci_dev *pdev, const struct pci_device_id *ent) dev->mem_start = card->phys_mem + BUF_OFFSET ( txBuffer[i][0][0]); dev->mem_end = card->phys_mem - + BUF_OFFSET ( txBuffer[i][NUM_TX_BUFFER][0]); + + BUF_OFFSET ( txBuffer[i][NUM_TX_BUFFER - 1][LEN_RX_BUFFER - 1]); dev->base_addr = card->pci_conf; dev->irq = card->irq; -- 2.20.1