| Message ID | 20200525095541.46673-1-horatiu.vultur@microchip.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | bridge: mrp: Fix out-of-bounds read in br_mrp_parse | expand |
On 25/05/2020 12:55, Horatiu Vultur wrote: > The issue was reported by syzbot. When the function br_mrp_parse was > called with a valid net_bridge_port, the net_bridge was an invalid > pointer. Therefore the check br->stp_enabled could pass/fail > depending where it was pointing in memory. > The fix consists of setting the net_bridge pointer if the port is a > valid pointer. > > Reported-by: syzbot+9c6f0f1f8e32223df9a4@syzkaller.appspotmail.com > Fixes: 6536993371fa ("bridge: mrp: Integrate MRP into the bridge") > Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com> > --- > net/bridge/br_mrp_netlink.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/net/bridge/br_mrp_netlink.c b/net/bridge/br_mrp_netlink.c > index 397e7f710772a..4a08a99519b04 100644 > --- a/net/bridge/br_mrp_netlink.c > +++ b/net/bridge/br_mrp_netlink.c > @@ -27,6 +27,12 @@ int br_mrp_parse(struct net_bridge *br, struct net_bridge_port *p, > struct nlattr *tb[IFLA_BRIDGE_MRP_MAX + 1]; > int err; > > + /* When this function is called for a port then the br pointer is > + * invalid, therefor set the br to point correctly > + */ > + if (p) > + br = p->br; > + > if (br->stp_enabled != BR_NO_STP) { > NL_SET_ERR_MSG_MOD(extack, "MRP can't be enabled if STP is already enabled"); > return -EINVAL; > You should tag the fix for net-next when it's intended for it. Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
From: Horatiu Vultur <horatiu.vultur@microchip.com> Date: Mon, 25 May 2020 09:55:41 +0000 > The issue was reported by syzbot. When the function br_mrp_parse was > called with a valid net_bridge_port, the net_bridge was an invalid > pointer. Therefore the check br->stp_enabled could pass/fail > depending where it was pointing in memory. > The fix consists of setting the net_bridge pointer if the port is a > valid pointer. > > Reported-by: syzbot+9c6f0f1f8e32223df9a4@syzkaller.appspotmail.com > Fixes: 6536993371fa ("bridge: mrp: Integrate MRP into the bridge") > Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com> Applied to net-next, thanks.
diff --git a/net/bridge/br_mrp_netlink.c b/net/bridge/br_mrp_netlink.c index 397e7f710772a..4a08a99519b04 100644 --- a/net/bridge/br_mrp_netlink.c +++ b/net/bridge/br_mrp_netlink.c @@ -27,6 +27,12 @@ int br_mrp_parse(struct net_bridge *br, struct net_bridge_port *p, struct nlattr *tb[IFLA_BRIDGE_MRP_MAX + 1]; int err; + /* When this function is called for a port then the br pointer is + * invalid, therefor set the br to point correctly + */ + if (p) + br = p->br; + if (br->stp_enabled != BR_NO_STP) { NL_SET_ERR_MSG_MOD(extack, "MRP can't be enabled if STP is already enabled"); return -EINVAL;
The issue was reported by syzbot. When the function br_mrp_parse was called with a valid net_bridge_port, the net_bridge was an invalid pointer. Therefore the check br->stp_enabled could pass/fail depending where it was pointing in memory. The fix consists of setting the net_bridge pointer if the port is a valid pointer. Reported-by: syzbot+9c6f0f1f8e32223df9a4@syzkaller.appspotmail.com Fixes: 6536993371fa ("bridge: mrp: Integrate MRP into the bridge") Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com> --- net/bridge/br_mrp_netlink.c | 6 ++++++ 1 file changed, 6 insertions(+)