On Wed, Jun 12, 2024 at 3:32 PM Mike Pattrick <[email protected]> wrote:
> When compiling with '-fsanitize=address,undefined', the "ovs-ofctl > ct-flush" test will yield the following undefined behavior flagged > by UBSan. This patch uses memcpy to move the 128bit value into the > stack before reading it. > > lib/ofp-prop.c:277:14: runtime error: load of misaligned address > for type 'union ovs_be128', which requires 8 byte alignment > ^ > #0 0x7735d4 in ofpprop_parse_u128 lib/ofp-prop.c:277 > #1 0x6c6c83 in ofp_ct_match_decode lib/ofp-ct.c:529 > #2 0x76f3b5 in ofp_print_nxt_ct_flush lib/ofp-print.c:959 > #3 0x76f3b5 in ofp_to_string__ lib/ofp-print.c:1206 > #4 0x76f3b5 in ofp_to_string lib/ofp-print.c:1264 > #5 0x770c0d in ofp_print lib/ofp-print.c:1308 > #6 0x484a9d in ofctl_ofp_print utilities/ovs-ofctl.c:4899 > #7 0x4ddb77 in ovs_cmdl_run_command__ lib/command-line.c:247 > #8 0x47f6b3 in main utilities/ovs-ofctl.c:186 > > Signed-off-by: Mike Pattrick <[email protected]> > --- > Hi Mike, this is interesting, do you have an idea why it didn't fail in CI by now? Also AFAIR the ofprops is supposed to be aligned to 8 bytes so unless the buffer itself isn't allocated at an address that is not itself 8 bytes aligned it shouldn't happen. In that case we might actually have a problem with other sizes. > lib/ofp-prop.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/lib/ofp-prop.c b/lib/ofp-prop.c > index 0a685750c..ed6365414 100644 > --- a/lib/ofp-prop.c > +++ b/lib/ofp-prop.c > @@ -271,10 +271,12 @@ enum ofperr > ofpprop_parse_u128(const struct ofpbuf *property, ovs_u128 *value) > { > ovs_be128 *p = property->msg; > + ovs_be128 aligned; > if (ofpbuf_msgsize(property) != sizeof *p) { > return OFPERR_OFPBPC_BAD_LEN; > } > - *value = ntoh128(*p); > + memcpy(&aligned, p, sizeof aligned); > + *value = ntoh128(aligned); > return 0; > } > > -- > 2.39.3 > > _______________________________________________ > dev mailing list > [email protected] > https://mail.openvswitch.org/mailman/listinfo/ovs-dev > > Thanks, Ales -- Ales Musil Senior Software Engineer - OVN Core Red Hat EMEA <https://www.redhat.com> [email protected] <https://red.ht/sig> _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
