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 4.19-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-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b2cd22be373a63d086d56637d7f1c8ac409672c4 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 8ab17f0da026..e1006ed4d90a 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -243,6 +243,7 @@ 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"; @@ -267,31 +268,38 @@ 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) {