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ixgbe: avoid premature Rx buffer reuse

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The page recycle code, incorrectly, relied on that a page fragment
could not be freed inside xdp_do_redirect(). This assumption leads to
that page fragments that are used by the stack/XDP redirect can be
reused and overwritten.

To avoid this, store the page count prior invoking xdp_do_redirect().

Fixes: 6453073987 ("ixgbe: add initial support for xdp redirect")
Reported-and-analyzed-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Tested-by: Sandeep Penigalapati <sandeep.penigalapati@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
This commit is contained in:
Björn Töpel 2020-08-25 19:27:35 +02:00 committed by Tony Nguyen
parent 75aab4e10a
commit a06316dc87
1 changed files with 17 additions and 7 deletions
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24
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
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@ -1945,7 +1945,8 @@ static inline bool ixgbe_page_is_reserved(struct page *page)
return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
}
static bool ixgbe_can_reuse_rx_page(struct ixgbe_rx_buffer *rx_buffer)
static bool ixgbe_can_reuse_rx_page(struct ixgbe_rx_buffer *rx_buffer,
int rx_buffer_pgcnt)
{
unsigned int pagecnt_bias = rx_buffer->pagecnt_bias;
struct page *page = rx_buffer->page;
@ -1956,7 +1957,7 @@ static bool ixgbe_can_reuse_rx_page(struct ixgbe_rx_buffer *rx_buffer)
#if (PAGE_SIZE < 8192)
/* if we are only owner of page we can reuse it */
if (unlikely((page_ref_count(page) - pagecnt_bias) > 1))
if (unlikely((rx_buffer_pgcnt - pagecnt_bias) > 1))
return false;
#else
/* The last offset is a bit aggressive in that we assume the
@ -2021,11 +2022,18 @@ static void ixgbe_add_rx_frag(struct ixgbe_ring *rx_ring,
static struct ixgbe_rx_buffer *ixgbe_get_rx_buffer(struct ixgbe_ring *rx_ring,
union ixgbe_adv_rx_desc *rx_desc,
struct sk_buff **skb,
const unsigned int size)
const unsigned int size,
int *rx_buffer_pgcnt)
{
struct ixgbe_rx_buffer *rx_buffer;
rx_buffer = &rx_ring->rx_buffer_info[rx_ring->next_to_clean];
*rx_buffer_pgcnt =
#if (PAGE_SIZE < 8192)
page_count(rx_buffer->page);
#else
0;
#endif
prefetchw(rx_buffer->page);
*skb = rx_buffer->skb;
@ -2055,9 +2063,10 @@ skip_sync:
static void ixgbe_put_rx_buffer(struct ixgbe_ring *rx_ring,
struct ixgbe_rx_buffer *rx_buffer,
struct sk_buff *skb)
struct sk_buff *skb,
int rx_buffer_pgcnt)
{
if (ixgbe_can_reuse_rx_page(rx_buffer)) {
if (ixgbe_can_reuse_rx_page(rx_buffer, rx_buffer_pgcnt)) {
/* hand second half of page back to the ring */
ixgbe_reuse_rx_page(rx_ring, rx_buffer);
} else {
@ -2303,6 +2312,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
union ixgbe_adv_rx_desc *rx_desc;
struct ixgbe_rx_buffer *rx_buffer;
struct sk_buff *skb;
int rx_buffer_pgcnt;
unsigned int size;
/* return some buffers to hardware, one at a time is too slow */
@ -2322,7 +2332,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
*/
dma_rmb();
rx_buffer = ixgbe_get_rx_buffer(rx_ring, rx_desc, &skb, size);
rx_buffer = ixgbe_get_rx_buffer(rx_ring, rx_desc, &skb, size, &rx_buffer_pgcnt);
/* retrieve a buffer from the ring */
if (!skb) {
@ -2367,7 +2377,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector,
break;
}
ixgbe_put_rx_buffer(rx_ring, rx_buffer, skb);
ixgbe_put_rx_buffer(rx_ring, rx_buffer, skb, rx_buffer_pgcnt);
cleaned_count++;
/* place incomplete frames back on ring for completion */