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author | Alexei Starovoitov <ast@kernel.org> | 2020-06-28 18:33:28 +0300 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2020-06-28 18:37:44 +0300 |
commit | 2bdeb3ed547d8822b2566797afa6c2584abdb119 (patch) | |
tree | b979388fd7d79fecd27e67e48833754be2a95fba /Documentation | |
parent | 7a64135f3229a808067e4bd29be15fe6856a9ae6 (diff) | |
parent | 53792fa45b1b17f78f18bcd0bd167674341297e8 (diff) | |
download | linux-2bdeb3ed547d8822b2566797afa6c2584abdb119.tar.xz |
Merge branch 'fix-sockmap'
John Fastabend says:
====================
Fix a splat introduced by recent changes to avoid skipping ingress policy
when kTLS is enabled. The RCU splat was introduced because in the non-TLS
case the caller is wrapped in an rcu_read_lock/unlock. But, in the TLS
case we have a reference to the psock and the caller did not wrap its
call in rcu_read_lock/unlock.
To fix extend the RCU section to include the redirect case which was
missed. From v1->v2 I changed the location a bit to simplify the code
some. See patch 1.
But, then Martin asked why it was not needed in the non-TLS case. The
answer for patch 1 was, as stated above, because the caller has the
rcu read lock. However, there was still a missing case where a BPF
user could in-theory line up a set of parameters to hit a case
where the code was entered from strparser side from a different context
then the initial caller. To hit this user would need a parser program
to return value greater than skb->len then an ENOMEM error could happen
in the strparser codepath triggering strparser to retry from a workqueue
and without rcu_read_lock original caller used. See patch 2 for details.
Finally, we don't actually have any selftests for parser returning a
value geater than skb->len so add one in patch 3. This is especially
needed because at least I don't have any code that uses the parser
to return value greater than skb->len. So I wouldn't have caught any
errors here in my own testing.
Thanks, John
v1->v2: simplify code in patch 1 some and add patches 2 and 3.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'Documentation')
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