[PATCH net] net: dsa: ksz: fix skb freeing
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STALE3353d
From: Vivien Didelot <hidden>
Date: 2017-08-09 20:49:29
Also in:
lkml
Subsystem:
microchip ksz series ethernet switch driver, networking [dsa], networking [general], the rest · Maintainers:
Woojung Huh, Andrew Lunn, Vladimir Oltean, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The DSA layer frees the original skb when an xmit function returns NULL, meaning an error occurred. But if the tagging code copied the original skb, it is responsible of freeing the copy if an error occurs. The ksz tagging code currently has two issues: if skb_put_padto fails, the skb copy is not freed, and the original skb will be freed twice. To fix that, move skb_put_padto inside both branches of the skb_tailroom condition, before freeing the original skb, and free the copy on error. Signed-off-by: Vivien Didelot <redacted> --- net/dsa/tag_ksz.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
index fab41de8e983..de66ca8e6201 100644
--- a/net/dsa/tag_ksz.c
+++ b/net/dsa/tag_ksz.c@@ -42,6 +42,9 @@ static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev) padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len; if (skb_tailroom(skb) >= padlen + KSZ_INGRESS_TAG_LEN) { + if (skb_put_padto(skb, skb->len + padlen)) + return NULL; + nskb = skb; } else { nskb = alloc_skb(NET_IP_ALIGN + skb->len +
@@ -56,13 +59,15 @@ static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev) skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head); skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len)); + + if (skb_put_padto(nskb, nskb->len + padlen)) { + kfree_skb(nskb); + return NULL; + } + kfree_skb(skb); } - /* skb is freed when it fails */ - if (skb_put_padto(nskb, nskb->len + padlen)) - return NULL; - tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN); tag[0] = 0; tag[1] = 1 << p->dp->index; /* destination port */
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2.14.0