This is a note to let you know that I've just added the patch titled

ipv4: fib: Fix metrics match when deleting a route

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: ipv4-fib-fix-metrics-match-when-deleting-a-route.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Sun Dec 31 11:12:48 CET 2017

From: Phil Sutter phil@nwl.cc Date: Tue, 19 Dec 2017 15:17:13 +0100 Subject: ipv4: fib: Fix metrics match when deleting a route

From: Phil Sutter phil@nwl.cc

[ Upstream commit d03a45572efa068fa64db211d6d45222660e76c5 ]

The recently added fib_metrics_match() causes a regression for routes with both RTAX_FEATURES and RTAX_CC_ALGO if the latter has TCP_CONG_NEEDS_ECN flag set:

| # ip link add d0 type dummy | # ip link set d0 up | # ip route add 172.29.29.0/24 dev d0 features ecn congctl dctcp | # ip route del 172.29.29.0/24 dev d0 features ecn congctl dctcp | RTNETLINK answers: No such process

During route insertion, fib_convert_metrics() detects that the given CC algo requires ECN and hence sets DST_FEATURE_ECN_CA bit in RTAX_FEATURES.

During route deletion though, fib_metrics_match() compares stored RTAX_FEATURES value with that from userspace (which obviously has no knowledge about DST_FEATURE_ECN_CA) and fails.

Fixes: 5f9ae3d9e7e4a ("ipv4: do metrics match when looking up and deleting a route") Signed-off-by: Phil Sutter phil@nwl.cc Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/fib_semantics.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -706,7 +706,7 @@ bool fib_metrics_match(struct fib_config

nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) { int type = nla_type(nla); - u32 val; + u32 fi_val, val;

if (!type) continue; @@ -723,7 +723,11 @@ bool fib_metrics_match(struct fib_config val = nla_get_u32(nla); }

- if (fi->fib_metrics->metrics[type - 1] != val) + fi_val = fi->fib_metrics->metrics[type - 1]; + if (type == RTAX_FEATURES) + fi_val &= ~DST_FEATURE_ECN_CA; + + if (fi_val != val) return false; }

Patches currently in stable-queue which might be from phil@nwl.cc are

queue-4.14/ipv4-fib-fix-metrics-match-when-deleting-a-route.patch