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@vger.kernel.org Acked-by: Jon Maloy jmaloy@redhat.com Signed-off-by: Hoang Le hoang.h.le@dektech.com.au --- net/tipc/bearer.c | 46 +++++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 19 deletions(-)

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c index d47e0b940ac9..443f8e5b9477 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -256,6 +256,7 @@ 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"; @@ -280,31 +281,38 @@ 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) {