From 9fe06a51287b2d41baef7ece94df34b5abf19b90 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Wed, 19 Jun 2019 15:30:44 +0100 Subject: [PATCH] iavf: fix dereference of null rx_buffer pointer A recent commit efa14c3985828d ("iavf: allow null RX descriptors") added a null pointer sanity check on rx_buffer, however, rx_buffer is being dereferenced before that check, which implies a null pointer dereference bug can potentially occur. Fix this by only dereferencing rx_buffer until after the null pointer check. Addresses-Coverity: ("Dereference before null check") Signed-off-by: Colin Ian King Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/iavf/iavf_txrx.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/iavf/iavf_txrx.c b/drivers/net/ethernet/intel/iavf/iavf_txrx.c index 1cde1601bc32..0cca1b589b56 100644 --- a/drivers/net/ethernet/intel/iavf/iavf_txrx.c +++ b/drivers/net/ethernet/intel/iavf/iavf_txrx.c @@ -1296,7 +1296,7 @@ static struct sk_buff *iavf_construct_skb(struct iavf_ring *rx_ring, struct iavf_rx_buffer *rx_buffer, unsigned int size) { - void *va = page_address(rx_buffer->page) + rx_buffer->page_offset; + void *va; #if (PAGE_SIZE < 8192) unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2; #else @@ -1308,6 +1308,7 @@ static struct sk_buff *iavf_construct_skb(struct iavf_ring *rx_ring, if (!rx_buffer) return NULL; /* prefetch first cache line of first page */ + va = page_address(rx_buffer->page) + rx_buffer->page_offset; prefetch(va); #if L1_CACHE_BYTES < 128 prefetch(va + L1_CACHE_BYTES); @@ -1362,7 +1363,7 @@ static struct sk_buff *iavf_build_skb(struct iavf_ring *rx_ring, struct iavf_rx_buffer *rx_buffer, unsigned int size) { - void *va = page_address(rx_buffer->page) + rx_buffer->page_offset; + void *va; #if (PAGE_SIZE < 8192) unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2; #else @@ -1374,6 +1375,7 @@ static struct sk_buff *iavf_build_skb(struct iavf_ring *rx_ring, if (!rx_buffer) return NULL; /* prefetch first cache line of first page */ + va = page_address(rx_buffer->page) + rx_buffer->page_offset; prefetch(va); #if L1_CACHE_BYTES < 128 prefetch(va + L1_CACHE_BYTES); -- 2.11.0