Dumitru Ceara <dce...@redhat.com> writes: > On 4/5/22 21:20, Aaron Conole wrote: >> Dumitru Ceara <dce...@redhat.com> writes: >> >>> On 4/5/22 16:41, Aaron Conole wrote: >>>> Dumitru Ceara <dce...@redhat.com> writes: >>>> >>>>> This is undefined behavior and was reported by UB Sanitizer: >>>>> lib/meta-flow.c:3445:16: runtime error: member access within null >>>>> pointer of type 'struct vl_mf_field' >>>>> #0 0x6aad0f in mf_get_vl_mff lib/meta-flow.c:3445 >>>>> #1 0x6d96d7 in mf_from_oxm_header lib/nx-match.c:260 >>>>> #2 0x6d9e2e in nx_pull_header__ lib/nx-match.c:341 >>>>> #3 0x6daafa in nx_pull_header lib/nx-match.c:488 >>>>> #4 0x6abcb6 in mf_vl_mff_nx_pull_header lib/meta-flow.c:3605 >>>>> #5 0x73b9be in decode_NXAST_RAW_REG_MOVE lib/ofp-actions.c:2652 >>>>> #6 0x764ccd in ofpact_decode lib/ofp-actions.inc2:4681 >>>>> [...] >>>>> lib/sset.c:315:12: runtime error: applying zero offset to null pointer >>>>> #0 0xcc2e6a in sset_at_position /root/ovs/lib/sset.c:315:12 >>>>> #1 0x5734b3 in port_dump_next >>>>> /root/ovs/ofproto/ofproto-dpif.c:4083:20 >>>>> [...] >>>>> lib/ovsdb-data.c:2194:56: runtime error: applying zero offset to null >>>>> pointer >>>>> #0 0x5e9530 in ovsdb_datum_added_removed >>>>> /root/ovs/lib/ovsdb-data.c:2194:56 >>>>> #1 0x4d6258 in update_row_ref_count >>>>> /root/ovs/ovsdb/transaction.c:335:17 >>>>> #2 0x4c360b in for_each_txn_row >>>>> /root/ovs/ovsdb/transaction.c:1572:33 >>>>> [...] >>>>> lib/ofpbuf.c:440:30: runtime error: applying zero offset to null pointer >>>>> #0 0x75066d in ofpbuf_push_uninit lib/ofpbuf.c:440 >>>>> #1 0x46ac8a in ovnacts_parse lib/actions.c:4190 >>>>> #2 0x46ad91 in ovnacts_parse_string lib/actions.c:4208 >>>>> #3 0x4106d1 in test_parse_actions tests/test-ovn.c:1324 >>>>> [...] >>>>> lib/ofp-actions.c:3205:22: runtime error: applying non-zero offset 2 to >>>>> null pointer >>>>> #0 0x6e1641 in set_field_split_str >>>>> /root/ovs/lib/ofp-actions.c:3205:22 >>>>> [...] >>>>> lib/tnl-ports.c:74:12: runtime error: applying zero offset to null >>>>> pointer >>>>> #0 0xceffe7 in tnl_port_cast /root/ovs/lib/tnl-ports.c:74:12 >>>>> #1 0xcf14c3 in map_insert /root/ovs/lib/tnl-ports.c:116:13 >>>>> [...] >>>>> ofproto/ofproto.c:8905:16: runtime error: applying zero offset to null >>>>> pointer >>>>> #0 0x556795 in eviction_group_hash_rule >>>>> /root/ovs/ofproto/ofproto.c:8905:16 >>>>> #1 0x503f8d in eviction_group_add_rule >>>>> /root/ovs/ofproto/ofproto.c:9022:42 >>>>> [...] >>>>> >>>>> Also, it's valid to have an empty ofpact list and we should be able to >>>>> try to iterate through it. >>>>> >>>>> UB Sanitizer report: >>>>> include/openvswitch/ofp-actions.h:222:12: runtime error: applying zero >>>>> offset to null pointer >>>>> #0 0x665d69 in ofpact_end >>>>> /root/ovs/./include/openvswitch/ofp-actions.h:222:12 >>>>> #1 0x66b2cf in ofpacts_put_openflow_actions >>>>> /root/ovs/lib/ofp-actions.c:8861:5 >>>>> #2 0x6ffdd1 in ofputil_encode_flow_mod >>>>> /root/ovs/lib/ofp-flow.c:447:9 >>>>> [...] >>>>> >>>>> Signed-off-by: Dumitru Ceara <dce...@redhat.com> >>>>> --- >>>>> v5: >>>>> - Rebase. >>>>> v4: >>>>> - Addressed Ilya's comments. >>>>> --- >>>> >>>> Glad to see that the undefined behavior got removed, BUT this >>>> can introduce some different undefined behavior - places where we >>>> have a calls to ofpbuf_at_...() always assume a valid pointer is >>>> returned. >>>> >>> >>> Thanks for the review! >>> >>>> I think it makes sense to abort if b->data is NULL in these cases. >>>> Maybe something like: >>>> >>>> ovs_abort(0, "invalid buffer data pointer"); >>>> >>>> WDYT? >>>> >>> >>> Calling ovs_abort() directly from openvswitch/util.h will be a challenge >>> because it's an internal function and the openvswitch/util.h header is >>> public. Worst case we just call ovs_assert() like we already do in >>> ofpbuf_at_assert(). >> >> Maybe we can expose ovs_abort as well? >> > > We can, but should we then expose all of the following, for consistency? > > OVS_NO_RETURN void ovs_abort(int err_no, const char *format, ...) > OVS_PRINTF_FORMAT(2, 3); > OVS_NO_RETURN void ovs_abort_valist(int err_no, const char *format, va_list) > OVS_PRINTF_FORMAT(2, 0); > OVS_NO_RETURN void ovs_fatal(int err_no, const char *format, ...) > OVS_PRINTF_FORMAT(2, 3); > OVS_NO_RETURN void ovs_fatal_valist(int err_no, const char *format, va_list) > OVS_PRINTF_FORMAT(2, 0);
I think it makes sense. Maybe Ilya/Ian disagrees >>> But, just to make sure I understood properly, you'd like to assert that >>> b->data is not NULL only in ofpbuf_at() and ofpbuf_at_assert(), right? >> >> right - only for those places where we have the assumption that the >> return must be !NULL >> > > Ok. > >>> Because the other ofpact_...() functions are also called in valid >>> scenarios on ofpbufs that have b->data = NULL. >>> > > [...] _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
