| Message ID | f1e771e52c4dce3db4884ac0e629d363d1676b75.1697037788.git.pabeni@redhat.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Commit | 1d6459245311d14cf57960cdfb808ebcf49213eb |
| Delegated to: | Matthieu Baerts |
| Headers | show |
| Series | [mptcp-net,v2] tcp: check mptcp-level constraints for backlog coalescing | expand |
| Context | Check | Description |
|---|---|---|
| matttbe/build | success | Build and static analysis OK |
| matttbe/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 7 lines checked |
| matttbe/KVM_Validation__normal__except_selftest_mptcp_join_ | success | Success! ✅ |
| matttbe/KVM_Validation__debug__except_selftest_mptcp_join_ | success | Success! ✅ |
| matttbe/KVM_Validation__normal__only_selftest_mptcp_join_ | success | Success! ✅ |
| matttbe/KVM_Validation__debug__only_selftest_mptcp_join_ | warning | Unstable: 1 failed test(s): selftest_mptcp_join |
Hi Paolo, Thank you for your modifications, that's great! Our CI did some validations and here is its report: - KVM Validation: normal (except selftest_mptcp_join): - Success! ✅: - Task: https://cirrus-ci.com/task/5873231270248448 - Summary: https://api.cirrus-ci.com/v1/artifact/task/5873231270248448/summary/summary.txt - KVM Validation: debug (except selftest_mptcp_join): - Success! ✅: - Task: https://cirrus-ci.com/task/6659777703444480 - Summary: https://api.cirrus-ci.com/v1/artifact/task/6659777703444480/summary/summary.txt - KVM Validation: normal (only selftest_mptcp_join): - Success! ✅: - Task: https://cirrus-ci.com/task/5533877796601856 - Summary: https://api.cirrus-ci.com/v1/artifact/task/5533877796601856/summary/summary.txt - KVM Validation: debug (only selftest_mptcp_join): - Unstable: 1 failed test(s): selftest_mptcp_join
On Wed, 11 Oct 2023, Paolo Abeni wrote: > The MPTCP protocol can acquire the subflow-level socket lock and > cause the tcp backlog usage. When inserting new skbs into the > backlog, the stack will try to coalesce them. > > Currently, we have no check in place to ensure that such coalescing > will respect the MPTCP-level DSS, and that may cause data stream > corruption, as reported by Christoph. > > Address the issue by adding the relevant admission check for coalescing > in tcp_add_backlog(). > > Note the issue is not easy to reproduce, as the MPTCP protocol tries > hard to avoid acquiring the subflow-level socket lock. > > Fixes: 648ef4b88673 ("mptcp: Implement MPTCP receive path") > Reported-by: Christoph Paasch <cpaasch@apple.com> > Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/420 > Signed-off-by: Paolo Abeni <pabeni@redhat.com> > --- > v1 -> v2: > - !coalesce (mat) > - typo in commit message (mat) Thanks Paolo, v2 LGTM: Reviewed-by: Mat Martineau <martineau@kernel.org> > --- > net/ipv4/tcp_ipv4.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c > index a441740616d7..4d66a8ab3b98 100644 > --- a/net/ipv4/tcp_ipv4.c > +++ b/net/ipv4/tcp_ipv4.c > @@ -1870,6 +1870,7 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, > #ifdef CONFIG_TLS_DEVICE > tail->decrypted != skb->decrypted || > #endif > + !mptcp_skb_can_collapse(tail, skb) || > thtail->doff != th->doff || > memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th))) > goto no_coalesce; > -- > 2.41.0 > > >
Hi Paolo, Mat, On 11/10/2023 17:23, Paolo Abeni wrote: > The MPTCP protocol can acquire the subflow-level socket lock and > cause the tcp backlog usage. When inserting new skbs into the > backlog, the stack will try to coalesce them. > > Currently, we have no check in place to ensure that such coalescing > will respect the MPTCP-level DSS, and that may cause data stream > corruption, as reported by Christoph. > > Address the issue by adding the relevant admission check for coalescing > in tcp_add_backlog(). > > Note the issue is not easy to reproduce, as the MPTCP protocol tries > hard to avoid acquiring the subflow-level socket lock. Thank you for the patch and the review! Now in our tree (fixes for -net): New patches for t/upstream-net and t/upstream: - 1d6459245311: tcp: check mptcp-level constraints for backlog coalescing - Results: 08ccf8391935..b490362cfb13 (export-net) - Results: a3a484f2dee3..54aab2945697 (export) Tests are now in progress: https://cirrus-ci.com/github/multipath-tcp/mptcp_net-next/export-net/20231012T083551 https://cirrus-ci.com/github/multipath-tcp/mptcp_net-next/export/20231012T083551 Cheers, Matt
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a441740616d7..4d66a8ab3b98 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1870,6 +1870,7 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, #ifdef CONFIG_TLS_DEVICE tail->decrypted != skb->decrypted || #endif + !mptcp_skb_can_collapse(tail, skb) || thtail->doff != th->doff || memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th))) goto no_coalesce;
The MPTCP protocol can acquire the subflow-level socket lock and cause the tcp backlog usage. When inserting new skbs into the backlog, the stack will try to coalesce them. Currently, we have no check in place to ensure that such coalescing will respect the MPTCP-level DSS, and that may cause data stream corruption, as reported by Christoph. Address the issue by adding the relevant admission check for coalescing in tcp_add_backlog(). Note the issue is not easy to reproduce, as the MPTCP protocol tries hard to avoid acquiring the subflow-level socket lock. Fixes: 648ef4b88673 ("mptcp: Implement MPTCP receive path") Reported-by: Christoph Paasch <cpaasch@apple.com> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/420 Signed-off-by: Paolo Abeni <pabeni@redhat.com> --- v1 -> v2: - !coalesce (mat) - typo in commit message (mat) --- net/ipv4/tcp_ipv4.c | 1 + 1 file changed, 1 insertion(+)