We don't need to continue parsing if already oversized. This is not very important, but fuzzer times out while parsing very long flow.
The check could be written as a single 'if' statement, but I found my variant much more readable. Reported-at: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35519 Signed-off-by: Ilya Maximets <i.maxim...@ovn.org> --- lib/odp-util.c | 9 +++++++++ tests/odp.at | 14 ++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/lib/odp-util.c b/lib/odp-util.c index 04a183c7c..7729a9060 100644 --- a/lib/odp-util.c +++ b/lib/odp-util.c @@ -6077,6 +6077,15 @@ odp_flow_from_string(const char *s, const struct simap *port_names, } retval = parse_odp_key_mask_attr(&context, s, key, mask); + + if (retval >= 0) { + if (nl_attr_oversized(key->size - NLA_HDRLEN)) { + retval = -E2BIG; + } else if (mask && nl_attr_oversized(mask->size - NLA_HDRLEN)) { + retval = -E2BIG; + } + } + if (retval < 0) { if (errorp) { *errorp = xasprintf("syntax error at %s", s); diff --git a/tests/odp.at b/tests/odp.at index dccafd9d3..07a5cfe39 100644 --- a/tests/odp.at +++ b/tests/odp.at @@ -449,6 +449,20 @@ odp_actions_from_string: error ]) AT_CLEANUP +AT_SETUP([OVS datapath keys parsing and formatting - keys too long]) +dnl Flow keys should fit into a single netlink message. +dnl Empty encap() takes 4 bytes. So, 16384 is too many, but 16383 still fits. +dnl We're getting 'duplicate attribute' error since it's not a logically valid +dnl sequence of keys. 'syntax error' indicates oversized list of keys. +keys=$(printf 'encap(),%.0s' $(seq 16382)) +echo "${keys}encap()" > keys.txt +echo "${keys}encap(),encap()" >> keys.txt +AT_CHECK([ovstest test-odp parse-keys < keys.txt | sed 's/encap(),//g'], [0], [dnl +odp_flow_key_to_flow: error (duplicate encap attribute in flow key; the flow key in error is: encap()) +odp_flow_from_string: error (syntax error at encap()) +]) +AT_CLEANUP + AT_SETUP([OVS datapath keys parsing and formatting - 33 nested encap ]) AT_DATA([odp-in.txt], [dnl encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap(encap())))))))))))))))))))))))))))))))) -- 2.26.3 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
