| Message ID | 20240904120842.3426084-2-dmantipov@yandex.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v5,1/2] net: sched: fix use-after-free in taprio_change() | expand |
Dmitry Antipov <dmantipov@yandex.ru> writes: > Fix possible use-after-free in 'taprio_dump()' by adding RCU > read-side critical section there. Never seen on x86 but > found on a KASAN-enabled arm64 system when investigating > https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa: > > [T15862] BUG: KASAN: slab-use-after-free in taprio_dump+0xa0c/0xbb0 > [T15862] Read of size 4 at addr ffff0000d4bb88f8 by task repro/15862 > [T15862] > [T15862] CPU: 0 UID: 0 PID: 15862 Comm: repro Not tainted 6.11.0-rc1-00293-gdefaf1a2113a-dirty #2 > [T15862] Hardware name: QEMU QEMU Virtual Machine, BIOS edk2-20240524-5.fc40 05/24/2024 > [T15862] Call trace: > [T15862] dump_backtrace+0x20c/0x220 > [T15862] show_stack+0x2c/0x40 > [T15862] dump_stack_lvl+0xf8/0x174 > [T15862] print_report+0x170/0x4d8 > [T15862] kasan_report+0xb8/0x1d4 > [T15862] __asan_report_load4_noabort+0x20/0x2c > [T15862] taprio_dump+0xa0c/0xbb0 > [T15862] tc_fill_qdisc+0x540/0x1020 > [T15862] qdisc_notify.isra.0+0x330/0x3a0 > [T15862] tc_modify_qdisc+0x7b8/0x1838 > [T15862] rtnetlink_rcv_msg+0x3c8/0xc20 > [T15862] netlink_rcv_skb+0x1f8/0x3d4 > [T15862] rtnetlink_rcv+0x28/0x40 > [T15862] netlink_unicast+0x51c/0x790 > [T15862] netlink_sendmsg+0x79c/0xc20 > [T15862] __sock_sendmsg+0xe0/0x1a0 > [T15862] ____sys_sendmsg+0x6c0/0x840 > [T15862] ___sys_sendmsg+0x1ac/0x1f0 > [T15862] __sys_sendmsg+0x110/0x1d0 > [T15862] __arm64_sys_sendmsg+0x74/0xb0 > [T15862] invoke_syscall+0x88/0x2e0 > [T15862] el0_svc_common.constprop.0+0xe4/0x2a0 > [T15862] do_el0_svc+0x44/0x60 > [T15862] el0_svc+0x50/0x184 > [T15862] el0t_64_sync_handler+0x120/0x12c > [T15862] el0t_64_sync+0x190/0x194 > [T15862] > [T15862] Allocated by task 15857: > [T15862] kasan_save_stack+0x3c/0x70 > [T15862] kasan_save_track+0x20/0x3c > [T15862] kasan_save_alloc_info+0x40/0x60 > [T15862] __kasan_kmalloc+0xd4/0xe0 > [T15862] __kmalloc_cache_noprof+0x194/0x334 > [T15862] taprio_change+0x45c/0x2fe0 > [T15862] tc_modify_qdisc+0x6a8/0x1838 > [T15862] rtnetlink_rcv_msg+0x3c8/0xc20 > [T15862] netlink_rcv_skb+0x1f8/0x3d4 > [T15862] rtnetlink_rcv+0x28/0x40 > [T15862] netlink_unicast+0x51c/0x790 > [T15862] netlink_sendmsg+0x79c/0xc20 > [T15862] __sock_sendmsg+0xe0/0x1a0 > [T15862] ____sys_sendmsg+0x6c0/0x840 > [T15862] ___sys_sendmsg+0x1ac/0x1f0 > [T15862] __sys_sendmsg+0x110/0x1d0 > [T15862] __arm64_sys_sendmsg+0x74/0xb0 > [T15862] invoke_syscall+0x88/0x2e0 > [T15862] el0_svc_common.constprop.0+0xe4/0x2a0 > [T15862] do_el0_svc+0x44/0x60 > [T15862] el0_svc+0x50/0x184 > [T15862] el0t_64_sync_handler+0x120/0x12c > [T15862] el0t_64_sync+0x190/0x194 > [T15862] > [T15862] Freed by task 6192: > [T15862] kasan_save_stack+0x3c/0x70 > [T15862] kasan_save_track+0x20/0x3c > [T15862] kasan_save_free_info+0x4c/0x80 > [T15862] poison_slab_object+0x110/0x160 > [T15862] __kasan_slab_free+0x3c/0x74 > [T15862] kfree+0x134/0x3c0 > [T15862] taprio_free_sched_cb+0x18c/0x220 > [T15862] rcu_core+0x920/0x1b7c > [T15862] rcu_core_si+0x10/0x1c > [T15862] handle_softirqs+0x2e8/0xd64 > [T15862] __do_softirq+0x14/0x20 > > Fixes: 18cdd2f0998a ("net/sched: taprio: taprio_dump and taprio_change are protected by rtnl_mutex") > Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> > --- > v5: add Fixes: and resend due to series change > v4: redesign to preserve original code as much as possible, > adjust commit message and subject to target net tree > v3: tweak commit message as suggested by Vinicius > v2: added to the series > --- Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> Cheers,
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 59fad74d5ff9..522eec6f92d1 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -2372,9 +2372,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) struct tc_mqprio_qopt opt = { 0 }; struct nlattr *nest, *sched_nest; - oper = rtnl_dereference(q->oper_sched); - admin = rtnl_dereference(q->admin_sched); - mqprio_qopt_reconstruct(dev, &opt); nest = nla_nest_start_noflag(skb, TCA_OPTIONS); @@ -2395,18 +2392,23 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) nla_put_u32(skb, TCA_TAPRIO_ATTR_TXTIME_DELAY, q->txtime_delay)) goto options_error; + rcu_read_lock(); + + oper = rtnl_dereference(q->oper_sched); + admin = rtnl_dereference(q->admin_sched); + if (oper && taprio_dump_tc_entries(skb, q, oper)) - goto options_error; + goto options_error_rcu; if (oper && dump_schedule(skb, oper)) - goto options_error; + goto options_error_rcu; if (!admin) goto done; sched_nest = nla_nest_start_noflag(skb, TCA_TAPRIO_ATTR_ADMIN_SCHED); if (!sched_nest) - goto options_error; + goto options_error_rcu; if (dump_schedule(skb, admin)) goto admin_error; @@ -2414,11 +2416,15 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) nla_nest_end(skb, sched_nest); done: + rcu_read_unlock(); return nla_nest_end(skb, nest); admin_error: nla_nest_cancel(skb, sched_nest); +options_error_rcu: + rcu_read_unlock(); + options_error: nla_nest_cancel(skb, nest);
Fix possible use-after-free in 'taprio_dump()' by adding RCU read-side critical section there. Never seen on x86 but found on a KASAN-enabled arm64 system when investigating https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa: [T15862] BUG: KASAN: slab-use-after-free in taprio_dump+0xa0c/0xbb0 [T15862] Read of size 4 at addr ffff0000d4bb88f8 by task repro/15862 [T15862] [T15862] CPU: 0 UID: 0 PID: 15862 Comm: repro Not tainted 6.11.0-rc1-00293-gdefaf1a2113a-dirty #2 [T15862] Hardware name: QEMU QEMU Virtual Machine, BIOS edk2-20240524-5.fc40 05/24/2024 [T15862] Call trace: [T15862] dump_backtrace+0x20c/0x220 [T15862] show_stack+0x2c/0x40 [T15862] dump_stack_lvl+0xf8/0x174 [T15862] print_report+0x170/0x4d8 [T15862] kasan_report+0xb8/0x1d4 [T15862] __asan_report_load4_noabort+0x20/0x2c [T15862] taprio_dump+0xa0c/0xbb0 [T15862] tc_fill_qdisc+0x540/0x1020 [T15862] qdisc_notify.isra.0+0x330/0x3a0 [T15862] tc_modify_qdisc+0x7b8/0x1838 [T15862] rtnetlink_rcv_msg+0x3c8/0xc20 [T15862] netlink_rcv_skb+0x1f8/0x3d4 [T15862] rtnetlink_rcv+0x28/0x40 [T15862] netlink_unicast+0x51c/0x790 [T15862] netlink_sendmsg+0x79c/0xc20 [T15862] __sock_sendmsg+0xe0/0x1a0 [T15862] ____sys_sendmsg+0x6c0/0x840 [T15862] ___sys_sendmsg+0x1ac/0x1f0 [T15862] __sys_sendmsg+0x110/0x1d0 [T15862] __arm64_sys_sendmsg+0x74/0xb0 [T15862] invoke_syscall+0x88/0x2e0 [T15862] el0_svc_common.constprop.0+0xe4/0x2a0 [T15862] do_el0_svc+0x44/0x60 [T15862] el0_svc+0x50/0x184 [T15862] el0t_64_sync_handler+0x120/0x12c [T15862] el0t_64_sync+0x190/0x194 [T15862] [T15862] Allocated by task 15857: [T15862] kasan_save_stack+0x3c/0x70 [T15862] kasan_save_track+0x20/0x3c [T15862] kasan_save_alloc_info+0x40/0x60 [T15862] __kasan_kmalloc+0xd4/0xe0 [T15862] __kmalloc_cache_noprof+0x194/0x334 [T15862] taprio_change+0x45c/0x2fe0 [T15862] tc_modify_qdisc+0x6a8/0x1838 [T15862] rtnetlink_rcv_msg+0x3c8/0xc20 [T15862] netlink_rcv_skb+0x1f8/0x3d4 [T15862] rtnetlink_rcv+0x28/0x40 [T15862] netlink_unicast+0x51c/0x790 [T15862] netlink_sendmsg+0x79c/0xc20 [T15862] __sock_sendmsg+0xe0/0x1a0 [T15862] ____sys_sendmsg+0x6c0/0x840 [T15862] ___sys_sendmsg+0x1ac/0x1f0 [T15862] __sys_sendmsg+0x110/0x1d0 [T15862] __arm64_sys_sendmsg+0x74/0xb0 [T15862] invoke_syscall+0x88/0x2e0 [T15862] el0_svc_common.constprop.0+0xe4/0x2a0 [T15862] do_el0_svc+0x44/0x60 [T15862] el0_svc+0x50/0x184 [T15862] el0t_64_sync_handler+0x120/0x12c [T15862] el0t_64_sync+0x190/0x194 [T15862] [T15862] Freed by task 6192: [T15862] kasan_save_stack+0x3c/0x70 [T15862] kasan_save_track+0x20/0x3c [T15862] kasan_save_free_info+0x4c/0x80 [T15862] poison_slab_object+0x110/0x160 [T15862] __kasan_slab_free+0x3c/0x74 [T15862] kfree+0x134/0x3c0 [T15862] taprio_free_sched_cb+0x18c/0x220 [T15862] rcu_core+0x920/0x1b7c [T15862] rcu_core_si+0x10/0x1c [T15862] handle_softirqs+0x2e8/0xd64 [T15862] __do_softirq+0x14/0x20 Fixes: 18cdd2f0998a ("net/sched: taprio: taprio_dump and taprio_change are protected by rtnl_mutex") Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> --- v5: add Fixes: and resend due to series change v4: redesign to preserve original code as much as possible, adjust commit message and subject to target net tree v3: tweak commit message as suggested by Vinicius v2: added to the series --- net/sched/sch_taprio.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)