This is a note to let you know that I've just added the patch titled tipc: fix unique bearer names sanity check to the 5.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tipc-fix-unique-bearer-names-sanity-check.patch and it can be found in the queue-5.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a2976701b49292d9d2bfa7763787c59be45d1447 Author: Hoang Le <hoang.h.le@xxxxxxxxxxxxxx> Date: Thu Apr 1 09:30:48 2021 +0700 tipc: fix unique bearer names sanity check [ Upstream commit f20a46c3044c3f75232b3d0e2d09af9b25efaf45 ] When enabling a bearer by name, we don't sanity check its name with higher slot in bearer list. This may have the effect that the name of an already enabled bearer bypasses the check. To fix the above issue, we just perform an extra checking with all existing bearers. Fixes: cb30a63384bc9 ("tipc: refactor function tipc_enable_bearer()") Cc: stable@xxxxxxxxxxxxxxx Acked-by: Jon Maloy <jmaloy@xxxxxxxxxx> Signed-off-by: Hoang Le <hoang.h.le@xxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c index 1090f21fcfac..0c8882052ba0 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -255,6 +255,7 @@ static int tipc_enable_bearer(struct net *net, const char *name, int bearer_id = 0; int res = -EINVAL; char *errstr = ""; + u32 i; if (!bearer_name_validate(name, &b_names)) { errstr = "illegal name"; @@ -279,31 +280,38 @@ static int tipc_enable_bearer(struct net *net, const char *name, prio = m->priority; /* Check new bearer vs existing ones and find free bearer id if any */ - while (bearer_id < MAX_BEARERS) { - b = rtnl_dereference(tn->bearer_list[bearer_id]); - if (!b) - break; + bearer_id = MAX_BEARERS; + i = MAX_BEARERS; + while (i-- != 0) { + b = rtnl_dereference(tn->bearer_list[i]); + if (!b) { + bearer_id = i; + continue; + } if (!strcmp(name, b->name)) { errstr = "already enabled"; NL_SET_ERR_MSG(extack, "Already enabled"); goto rejected; } - bearer_id++; - if (b->priority != prio) - continue; - if (++with_this_prio <= 2) - continue; - pr_warn("Bearer <%s>: already 2 bearers with priority %u\n", - name, prio); - if (prio == TIPC_MIN_LINK_PRI) { - errstr = "cannot adjust to lower"; - NL_SET_ERR_MSG(extack, "Cannot adjust to lower"); - goto rejected; + + if (b->priority == prio && + (++with_this_prio > 2)) { + pr_warn("Bearer <%s>: already 2 bearers with priority %u\n", + name, prio); + + if (prio == TIPC_MIN_LINK_PRI) { + errstr = "cannot adjust to lower"; + NL_SET_ERR_MSG(extack, "Cannot adjust to lower"); + goto rejected; + } + + pr_warn("Bearer <%s>: trying with adjusted priority\n", + name); + prio--; + bearer_id = MAX_BEARERS; + i = MAX_BEARERS; + with_this_prio = 1; } - pr_warn("Bearer <%s>: trying with adjusted priority\n", name); - prio--; - bearer_id = 0; - with_this_prio = 1; } if (bearer_id >= MAX_BEARERS) {