Fix panic when trying to delete non-existent gateway in multipath route.

IF non-existend gateway was specified, the code responsible for calculating
 an updated nexthop group, returned the same already-used nexthop group.
After the route table update, the operation result contained the same
 old & new nexthop groups. Thus, the code responsible for decomposing
 the notification to the list of simple nexthop-level notifications,
 was not able to find any differences. As a result, it hasn't updated any
  of the "simple" notification fields, resulting in empty rtentry pointer.
This empty pointer was the direct reason of a panic.

Fix the problem by returning ESRCH when the new nexthop group is the same
 as the old one after applying gateway filter.

Reported by:	Michael <michael.adm at gmail.com>
PR:		255665
MFC after:	3 days
This commit is contained in:
Alexander V. Chernikov 2021-05-07 20:36:50 +00:00
parent ac200a9c38
commit aad59c79f5
2 changed files with 11 additions and 6 deletions

View File

@ -181,10 +181,15 @@ del_route_mpath(struct rib_head *rh, struct rt_addrinfo *info,
if ((info->rti_info[RTAX_GATEWAY] == NULL) && (info->rti_filter == NULL))
return (ESRCH);
error = nhgrp_get_filtered_group(rh, nhg, gw_filter_func, (void *)&ri,
&rnd);
if (error == 0)
error = nhgrp_get_filtered_group(rh, nhg, gw_filter_func, (void *)&ri, &rnd);
if (error == 0) {
if (rnd.rnd_nhgrp == nhg) {
/* No gateway match, unreference new group and return. */
nhop_free_any(rnd.rnd_nhop);
return (ESRCH);
}
error = change_route_nhop(rh, rt, info, &rnd, rc);
}
return (error);
}

View File

@ -578,9 +578,9 @@ nhgrp_get_group(struct rib_head *rh, struct weightened_nhop *wn, int num_nhops,
}
/*
* Creates new nexthop group based on @src group with the nexthops defined in bitmask
* @nhop_mask removed.
* Returns referenced nexthop group or NULL on failure.
* Creates new nexthop group based on @src group without the nexthops
* chosen by @flt_func.
* Returns 0 on success, storring the reference nhop group/object in @rnd.
*/
int
nhgrp_get_filtered_group(struct rib_head *rh, const struct nhgrp_object *src,