Messages in this thread Patch in this message |  | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.8 20/49] net: __skb_flow_dissect() must cap its return value | Date | Sat, 19 Nov 2016 10:23:12 +0100 |
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4.8-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
[ Upstream commit 34fad54c2537f7c99d07375e50cb30aa3c23bd83 ]
After Tom patch, thoff field could point past the end of the buffer, this could fool some callers.
If an skb was provided, skb->len should be the upper limit. If not, hlen is supposed to be the upper limit.
Fixes: a6e544b0a88b ("flow_dissector: Jump to exit code in __skb_flow_dissect") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Yibin Yang <yibyang@cisco.com Acked-by: Alexander Duyck <alexander.h.duyck@intel.com> Acked-by: Willem de Bruijn <willemb@google.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/core/flow_dissector.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
--- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -118,7 +118,7 @@ bool __skb_flow_dissect(const struct sk_ struct flow_dissector_key_tags *key_tags; struct flow_dissector_key_keyid *key_keyid; u8 ip_proto = 0; - bool ret = false; + bool ret; if (!data) { data = skb->data; @@ -481,12 +481,17 @@ ip_proto_again: out_good: ret = true; -out_bad: + key_control->thoff = (u16)nhoff; +out: key_basic->n_proto = proto; key_basic->ip_proto = ip_proto; - key_control->thoff = (u16)nhoff; return ret; + +out_bad: + ret = false; + key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen); + goto out; } EXPORT_SYMBOL(__skb_flow_dissect);
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