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| author | Florian Fainelli <f.fainelli@gmail.com> | 2017-08-22 15:12:15 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-23 20:33:49 -0700 |
| commit | 49716679248a0bf64d8914711b2d1ea48751853e (patch) | |
| tree | 75ab119854f9db3c887341aa214c0332ac945b5e /net/dsa | |
| parent | cd0a137acbb66208368353723f5f1480995cf1c4 (diff) | |
| download | linux-49716679248a0bf64d8914711b2d1ea48751853e.tar.gz linux-49716679248a0bf64d8914711b2d1ea48751853e.tar.bz2 linux-49716679248a0bf64d8914711b2d1ea48751853e.zip | |
net: dsa: skb_put_padto() already frees nskb
The first call of skb_put_padto() will free up the SKB on error, but we
return NULL which tells dsa_slave_xmit() that the original SKB should be
freed so this would lead to a double free here.
The second skb_put_padto() already frees the passed sk_buff reference
upon error, so calling kfree_skb() on it again is not necessary.
Detected by CoverityScan, CID#1416687 ("USE_AFTER_FREE")
Fixes: e71cb9e00922 ("net: dsa: ksz: fix skb freeing")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Woojung Huh <Woojung.Huh@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dsa')
| -rw-r--r-- | net/dsa/tag_ksz.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c index de66ca8e6201..3bd6e2a83125 100644 --- a/net/dsa/tag_ksz.c +++ b/net/dsa/tag_ksz.c @@ -42,7 +42,8 @@ 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)) + /* Let dsa_slave_xmit() free skb */ + if (__skb_put_padto(skb, skb->len + padlen, false)) return NULL; nskb = skb; @@ -60,10 +61,11 @@ static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev) 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); + /* Let skb_put_padto() free nskb, and let dsa_slave_xmit() free + * skb + */ + if (skb_put_padto(nskb, nskb->len + padlen)) return NULL; - } kfree_skb(skb); } |