| Message ID | 20250110153546.41344-1-jhs@mojatatu.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,1/1] net: sched: fix ets qdisc OOB Indexing | expand |
Jamal Hadi Salim <jhs@mojatatu.com> writes: > Haowei Yan <g1042620637@gmail.com> found that ets_class_from_arg() can > index an Out-Of-Bound class in ets_class_from_arg() when passed clid of > 0. The overflow may cause local privilege escalation. > > [ 18.852298] ------------[ cut here ]------------ > [ 18.853271] UBSAN: array-index-out-of-bounds in net/sched/sch_ets.c:93:20 > [ 18.853743] index 18446744073709551615 is out of range for type 'ets_class [16]' > [ 18.854254] CPU: 0 UID: 0 PID: 1275 Comm: poc Not tainted 6.12.6-dirty #17 > [ 18.854821] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 > [ 18.856532] Call Trace: > [ 18.857441] <TASK> > [ 18.858227] dump_stack_lvl+0xc2/0xf0 > [ 18.859607] dump_stack+0x10/0x20 > [ 18.860908] __ubsan_handle_out_of_bounds+0xa7/0xf0 > [ 18.864022] ets_class_change+0x3d6/0x3f0 > [ 18.864322] tc_ctl_tclass+0x251/0x910 > [ 18.864587] ? lock_acquire+0x5e/0x140 > [ 18.865113] ? __mutex_lock+0x9c/0xe70 > [ 18.866009] ? __mutex_lock+0xa34/0xe70 > [ 18.866401] rtnetlink_rcv_msg+0x170/0x6f0 > [ 18.866806] ? __lock_acquire+0x578/0xc10 > [ 18.867184] ? __pfx_rtnetlink_rcv_msg+0x10/0x10 > [ 18.867503] netlink_rcv_skb+0x59/0x110 > [ 18.867776] rtnetlink_rcv+0x15/0x30 > [ 18.868159] netlink_unicast+0x1c3/0x2b0 > [ 18.868440] netlink_sendmsg+0x239/0x4b0 > [ 18.868721] ____sys_sendmsg+0x3e2/0x410 > [ 18.869012] ___sys_sendmsg+0x88/0xe0 > [ 18.869276] ? rseq_ip_fixup+0x198/0x260 > [ 18.869563] ? rseq_update_cpu_node_id+0x10a/0x190 > [ 18.869900] ? trace_hardirqs_off+0x5a/0xd0 > [ 18.870196] ? syscall_exit_to_user_mode+0xcc/0x220 > [ 18.870547] ? do_syscall_64+0x93/0x150 > [ 18.870821] ? __memcg_slab_free_hook+0x69/0x290 > [ 18.871157] __sys_sendmsg+0x69/0xd0 > [ 18.871416] __x64_sys_sendmsg+0x1d/0x30 > [ 18.871699] x64_sys_call+0x9e2/0x2670 > [ 18.871979] do_syscall_64+0x87/0x150 > [ 18.873280] ? do_syscall_64+0x93/0x150 > [ 18.874742] ? lock_release+0x7b/0x160 > [ 18.876157] ? do_user_addr_fault+0x5ce/0x8f0 > [ 18.877833] ? irqentry_exit_to_user_mode+0xc2/0x210 > [ 18.879608] ? irqentry_exit+0x77/0xb0 > [ 18.879808] ? clear_bhb_loop+0x15/0x70 > [ 18.880023] ? clear_bhb_loop+0x15/0x70 > [ 18.880223] ? clear_bhb_loop+0x15/0x70 > [ 18.880426] entry_SYSCALL_64_after_hwframe+0x76/0x7e > [ 18.880683] RIP: 0033:0x44a957 > [ 18.880851] Code: ff ff e8 fc 00 00 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 8974 24 10 > [ 18.881766] RSP: 002b:00007ffcdd00fad8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > [ 18.882149] RAX: ffffffffffffffda RBX: 00007ffcdd010db8 RCX: 000000000044a957 > [ 18.882507] RDX: 0000000000000000 RSI: 00007ffcdd00fb70 RDI: 0000000000000003 > [ 18.885037] RBP: 00007ffcdd010bc0 R08: 000000000703c770 R09: 000000000703c7c0 > [ 18.887203] R10: 0000000000000080 R11: 0000000000000246 R12: 0000000000000001 > [ 18.888026] R13: 00007ffcdd010da8 R14: 00000000004ca7d0 R15: 0000000000000001 > [ 18.888395] </TASK> > [ 18.888610] ---[ end trace ]--- > > Fixes: dcc68b4d8084 ("net: sch_ets: Add a new Qdisc") > Reported-by: Haowei Yan <g1042620637@gmail.com> > Suggested-by: Haowei Yan <g1042620637@gmail.com> > Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> > --- > net/sched/sch_ets.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/net/sched/sch_ets.c b/net/sched/sch_ets.c > index f80bc05d4c5a..f27b50daae58 100644 > --- a/net/sched/sch_ets.c > +++ b/net/sched/sch_ets.c > @@ -91,6 +91,8 @@ ets_class_from_arg(struct Qdisc *sch, unsigned long arg) > { > struct ets_sched *q = qdisc_priv(sch); > > + if (arg == 0 || arg >= q->nbands) > + return NULL; > return &q->classes[arg - 1]; > } OK, It looks like RTM_NEWTCLASS with NLM_F_CREATE and a not-found clid would go to ets_class_change(), where there is code that seemingly would bounce not-found classes (if (!cl) ...), but that never triggers because ets_class_from_arg just always returns a pointer. I'm looking around and it looks like in the other call chains that end with ets_class_from_arg(), cl comes from the find callback and therefore should be safe. Patch looks good, thanks! Reviewed-by: Petr Machata <petrm@nvidia.com>
On Fri, Jan 10, 2025 at 4:35 PM Jamal Hadi Salim <jhs@mojatatu.com> wrote: > > Haowei Yan <g1042620637@gmail.com> found that ets_class_from_arg() can > index an Out-Of-Bound class in ets_class_from_arg() when passed clid of > 0. The overflow may cause local privilege escalation. > > [ 18.852298] ------------[ cut here ]------------ > [ 18.853271] UBSAN: array-index-out-of-bounds in net/sched/sch_ets.c:93:20 > [ 18.853743] index 18446744073709551615 is out of range for type 'ets_class [16]' > [ 18.854254] CPU: 0 UID: 0 PID: 1275 Comm: poc Not tainted 6.12.6-dirty #17 > [ 18.854821] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 > Fixes: dcc68b4d8084 ("net: sch_ets: Add a new Qdisc") > Reported-by: Haowei Yan <g1042620637@gmail.com> > Suggested-by: Haowei Yan <g1042620637@gmail.com> > Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> > --- > net/sched/sch_ets.c | 2 ++ > 1 file changed, 2 insertions(+) Reviewed-by: Eric Dumazet <edumazet@google.com>
diff --git a/net/sched/sch_ets.c b/net/sched/sch_ets.c index f80bc05d4c5a..f27b50daae58 100644 --- a/net/sched/sch_ets.c +++ b/net/sched/sch_ets.c @@ -91,6 +91,8 @@ ets_class_from_arg(struct Qdisc *sch, unsigned long arg) { struct ets_sched *q = qdisc_priv(sch); + if (arg == 0 || arg >= q->nbands) + return NULL; return &q->classes[arg - 1]; }
Haowei Yan <g1042620637@gmail.com> found that ets_class_from_arg() can index an Out-Of-Bound class in ets_class_from_arg() when passed clid of 0. The overflow may cause local privilege escalation. [ 18.852298] ------------[ cut here ]------------ [ 18.853271] UBSAN: array-index-out-of-bounds in net/sched/sch_ets.c:93:20 [ 18.853743] index 18446744073709551615 is out of range for type 'ets_class [16]' [ 18.854254] CPU: 0 UID: 0 PID: 1275 Comm: poc Not tainted 6.12.6-dirty #17 [ 18.854821] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 [ 18.856532] Call Trace: [ 18.857441] <TASK> [ 18.858227] dump_stack_lvl+0xc2/0xf0 [ 18.859607] dump_stack+0x10/0x20 [ 18.860908] __ubsan_handle_out_of_bounds+0xa7/0xf0 [ 18.864022] ets_class_change+0x3d6/0x3f0 [ 18.864322] tc_ctl_tclass+0x251/0x910 [ 18.864587] ? lock_acquire+0x5e/0x140 [ 18.865113] ? __mutex_lock+0x9c/0xe70 [ 18.866009] ? __mutex_lock+0xa34/0xe70 [ 18.866401] rtnetlink_rcv_msg+0x170/0x6f0 [ 18.866806] ? __lock_acquire+0x578/0xc10 [ 18.867184] ? __pfx_rtnetlink_rcv_msg+0x10/0x10 [ 18.867503] netlink_rcv_skb+0x59/0x110 [ 18.867776] rtnetlink_rcv+0x15/0x30 [ 18.868159] netlink_unicast+0x1c3/0x2b0 [ 18.868440] netlink_sendmsg+0x239/0x4b0 [ 18.868721] ____sys_sendmsg+0x3e2/0x410 [ 18.869012] ___sys_sendmsg+0x88/0xe0 [ 18.869276] ? rseq_ip_fixup+0x198/0x260 [ 18.869563] ? rseq_update_cpu_node_id+0x10a/0x190 [ 18.869900] ? trace_hardirqs_off+0x5a/0xd0 [ 18.870196] ? syscall_exit_to_user_mode+0xcc/0x220 [ 18.870547] ? do_syscall_64+0x93/0x150 [ 18.870821] ? __memcg_slab_free_hook+0x69/0x290 [ 18.871157] __sys_sendmsg+0x69/0xd0 [ 18.871416] __x64_sys_sendmsg+0x1d/0x30 [ 18.871699] x64_sys_call+0x9e2/0x2670 [ 18.871979] do_syscall_64+0x87/0x150 [ 18.873280] ? do_syscall_64+0x93/0x150 [ 18.874742] ? lock_release+0x7b/0x160 [ 18.876157] ? do_user_addr_fault+0x5ce/0x8f0 [ 18.877833] ? irqentry_exit_to_user_mode+0xc2/0x210 [ 18.879608] ? irqentry_exit+0x77/0xb0 [ 18.879808] ? clear_bhb_loop+0x15/0x70 [ 18.880023] ? clear_bhb_loop+0x15/0x70 [ 18.880223] ? clear_bhb_loop+0x15/0x70 [ 18.880426] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 18.880683] RIP: 0033:0x44a957 [ 18.880851] Code: ff ff e8 fc 00 00 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 8974 24 10 [ 18.881766] RSP: 002b:00007ffcdd00fad8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 18.882149] RAX: ffffffffffffffda RBX: 00007ffcdd010db8 RCX: 000000000044a957 [ 18.882507] RDX: 0000000000000000 RSI: 00007ffcdd00fb70 RDI: 0000000000000003 [ 18.885037] RBP: 00007ffcdd010bc0 R08: 000000000703c770 R09: 000000000703c7c0 [ 18.887203] R10: 0000000000000080 R11: 0000000000000246 R12: 0000000000000001 [ 18.888026] R13: 00007ffcdd010da8 R14: 00000000004ca7d0 R15: 0000000000000001 [ 18.888395] </TASK> [ 18.888610] ---[ end trace ]--- Fixes: dcc68b4d8084 ("net: sch_ets: Add a new Qdisc") Reported-by: Haowei Yan <g1042620637@gmail.com> Suggested-by: Haowei Yan <g1042620637@gmail.com> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> --- net/sched/sch_ets.c | 2 ++ 1 file changed, 2 insertions(+)