diff options
| author | Toke Høiland-Jørgensen <toke@redhat.com> | 2019-04-04 15:01:33 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-04-04 10:55:59 -0700 |
| commit | c87b4ecdbe8db27867a7b7f840291cd843406bd7 (patch) | |
| tree | 745972ccb1eada0d1672c97b65bbde019890316c /net | |
| parent | b2100cc56fca8c51d28aa42a9f1fbcb2cf351996 (diff) | |
sch_cake: Make sure we can write the IP header before changing DSCP bits
There is not actually any guarantee that the IP headers are valid before we
access the DSCP bits of the packets. Fix this using the same approach taken
in sch_dsmark.
Reported-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sched/sch_cake.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c index a3b55e18df04..259d97bc2abd 100644 --- a/net/sched/sch_cake.c +++ b/net/sched/sch_cake.c @@ -1517,16 +1517,27 @@ static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free) static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash) { + int wlen = skb_network_offset(skb); u8 dscp; switch (tc_skb_protocol(skb)) { case htons(ETH_P_IP): + wlen += sizeof(struct iphdr); + if (!pskb_may_pull(skb, wlen) || + skb_try_make_writable(skb, wlen)) + return 0; + dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2; if (wash && dscp) ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0); return dscp; case htons(ETH_P_IPV6): + wlen += sizeof(struct ipv6hdr); + if (!pskb_may_pull(skb, wlen) || + skb_try_make_writable(skb, wlen)) + return 0; + dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2; if (wash && dscp) ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0); |