diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2022-05-10 17:57:34 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-05-12 01:06:42 +0300 |
| commit | 8b796475fd7882663a870456466a4fb315cc1bd6 (patch) | |
| tree | cf45a0626337a12ad074bde229bce94890aee34d /include/net/tc_act | |
| parent | 3cc5c6a7829a67d943a8e9c42edbcc0db18493e2 (diff) | |
| download | linux-8b796475fd7882663a870456466a4fb315cc1bd6.tar.xz | |
net/sched: act_pedit: really ensure the skb is writable
Currently pedit tries to ensure that the accessed skb offset
is writable via skb_unclone(). The action potentially allows
touching any skb bytes, so it may end-up modifying shared data.
The above causes some sporadic MPTCP self-test failures, due to
this code:
tc -n $ns2 filter add dev ns2eth$i egress \
protocol ip prio 1000 \
handle 42 fw \
action pedit munge offset 148 u8 invert \
pipe csum tcp \
index 100
The above modifies a data byte outside the skb head and the skb is
a cloned one, carrying a TCP output packet.
This change addresses the issue by keeping track of a rough
over-estimate highest skb offset accessed by the action and ensuring
such offset is really writable.
Note that this may cause performance regressions in some scenarios,
but hopefully pedit is not in the critical path.
Fixes: db2c24175d14 ("act_pedit: access skb->data safely")
Acked-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Tested-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/1fcf78e6679d0a287dd61bb0f04730ce33b3255d.1652194627.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/net/tc_act')
| -rw-r--r-- | include/net/tc_act/tc_pedit.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/net/tc_act/tc_pedit.h b/include/net/tc_act/tc_pedit.h index 748cf87a4d7e..3e02709a1df6 100644 --- a/include/net/tc_act/tc_pedit.h +++ b/include/net/tc_act/tc_pedit.h @@ -14,6 +14,7 @@ struct tcf_pedit { struct tc_action common; unsigned char tcfp_nkeys; unsigned char tcfp_flags; + u32 tcfp_off_max_hint; struct tc_pedit_key *tcfp_keys; struct tcf_pedit_key_ex *tcfp_keys_ex; }; |