net: sched: validate stab values

commit e323d865b36134e8c5c82c834df89109a5c60dab upstream.

iproute2 package is well behaved, but malicious user space can
provide illegal shift values and trigger UBSAN reports.

Add stab parameter to red_check_params() to validate user input.

syzbot reported:

UBSAN: shift-out-of-bounds in ./include/net/red.h:312:18
shift exponent 111 is too large for 64-bit type 'long unsigned int'
CPU: 1 PID: 14662 Comm: syz-executor.3 Not tainted 5.12.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
 __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327
 red_calc_qavg_from_idle_time include/net/red.h:312 [inline]
 red_calc_qavg include/net/red.h:353 [inline]
 choke_enqueue.cold+0x18/0x3dd net/sched/sch_choke.c:221
 __dev_xmit_skb net/core/dev.c:3837 [inline]
 __dev_queue_xmit+0x1943/0x2e00 net/core/dev.c:4150
 neigh_hh_output include/net/neighbour.h:499 [inline]
 neigh_output include/net/neighbour.h:508 [inline]
 ip6_finish_output2+0x911/0x1700 net/ipv6/ip6_output.c:117
 __ip6_finish_output net/ipv6/ip6_output.c:182 [inline]
 __ip6_finish_output+0x4c1/0xe10 net/ipv6/ip6_output.c:161
 ip6_finish_output+0x35/0x200 net/ipv6/ip6_output.c:192
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:215
 dst_output include/net/dst.h:448 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 NF_HOOK include/linux/netfilter.h:295 [inline]
 ip6_xmit+0x127e/0x1eb0 net/ipv6/ip6_output.c:320
 inet6_csk_xmit+0x358/0x630 net/ipv6/inet6_connection_sock.c:135
 dccp_transmit_skb+0x973/0x12c0 net/dccp/output.c:138
 dccp_send_reset+0x21b/0x2b0 net/dccp/output.c:535
 dccp_finish_passive_close net/dccp/proto.c:123 [inline]
 dccp_finish_passive_close+0xed/0x140 net/dccp/proto.c:118
 dccp_terminate_connection net/dccp/proto.c:958 [inline]
 dccp_close+0xb3c/0xe60 net/dccp/proto.c:1028
 inet_release+0x12e/0x280 net/ipv4/af_inet.c:431
 inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:478
 __sock_release+0xcd/0x280 net/socket.c:599
 sock_close+0x18/0x20 net/socket.c:1258
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]

Fixes: 8afa10cbe281 ("net_sched: red: Avoid illegal values")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/red.h b/include/net/red.h
index e21e7fd4fe077af986682382d7cc855adee1cd50..8fe55b8b2fb81c46fb242d25fb5e45c73e124094 100644 (file)
--- a/include/net/red.h
+++ b/include/net/red.h
@@ -168,7 +168,8 @@ static inline void red_set_vars(struct red_vars *v)
        v->qcount       = -1;
 }
 
-static inline bool red_check_params(u32 qth_min, u32 qth_max, u8 Wlog, u8 Scell_log)
+static inline bool red_check_params(u32 qth_min, u32 qth_max, u8 Wlog,
+                                   u8 Scell_log, u8 *stab)
 {
        if (fls(qth_min) + Wlog > 32)
                return false;
@@ -178,6 +179,13 @@ static inline bool red_check_params(u32 qth_min, u32 qth_max, u8 Wlog, u8 Scell_
                return false;
        if (qth_max < qth_min)
                return false;
+       if (stab) {
+               int i;
+
+               for (i = 0; i < RED_STAB_SIZE; i++)
+                       if (stab[i] >= 32)
+                               return false;
+       }
        return true;
 }
 

diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index d058397d284bfcce5fc871549ab56d5b78a5fc5d..8b72aed77ed4f76deae6cbf3eb93036c57f8a81a 100644 (file)
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -355,6 +355,7 @@ static int choke_change(struct Qdisc *sch, struct nlattr *opt,
        struct sk_buff **old = NULL;
        unsigned int mask;
        u32 max_P;
+       u8 *stab;
 
        if (opt == NULL)
                return -EINVAL;
@@ -370,8 +371,8 @@ static int choke_change(struct Qdisc *sch, struct nlattr *opt,
        max_P = tb[TCA_CHOKE_MAX_P] ? nla_get_u32(tb[TCA_CHOKE_MAX_P]) : 0;
 
        ctl = nla_data(tb[TCA_CHOKE_PARMS]);
-
-       if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Scell_log))
+       stab = nla_data(tb[TCA_CHOKE_STAB]);
+       if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Scell_log, stab))
                return -EINVAL;
 
        if (ctl->limit > CHOKE_MAX_QUEUE)
@@ -421,7 +422,7 @@ static int choke_change(struct Qdisc *sch, struct nlattr *opt,
 
        red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog,
                      ctl->Plog, ctl->Scell_log,
-                     nla_data(tb[TCA_CHOKE_STAB]),
+                     stab,
                      max_P);
        red_set_vars(&q->vars);
 

diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
index 6f94bca75520bfbbba23efaff457a81c7389dbbe..db7a91a29b59c74b80fe5a4f9826ab0edadb8f0d 100644 (file)
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -357,7 +357,7 @@ static inline int gred_change_vq(struct Qdisc *sch, int dp,
        struct gred_sched *table = qdisc_priv(sch);
        struct gred_sched_data *q = table->tab[dp];
 
-       if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Scell_log))
+       if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Scell_log, stab))
                return -EINVAL;
 
        if (!q) {

diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index a3dc2118539b90deee2fd14ab90bb9feddd3a19d..e42f890fa1478e0ffa9dbe19bdde1d4b32e6670f 100644 (file)
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -199,6 +199,7 @@ static int red_change(struct Qdisc *sch, struct nlattr *opt,
        struct Qdisc *child = NULL;
        int err;
        u32 max_P;
+       u8 *stab;
 
        if (opt == NULL)
                return -EINVAL;
@@ -214,7 +215,9 @@ static int red_change(struct Qdisc *sch, struct nlattr *opt,
        max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
 
        ctl = nla_data(tb[TCA_RED_PARMS]);
-       if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Scell_log))
+       stab = nla_data(tb[TCA_RED_STAB]);
+       if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog,
+                             ctl->Scell_log, stab))
                return -EINVAL;
 
        if (ctl->limit > 0) {
@@ -240,7 +243,7 @@ static int red_change(struct Qdisc *sch, struct nlattr *opt,
        red_set_parms(&q->parms,
                      ctl->qth_min, ctl->qth_max, ctl->Wlog,
                      ctl->Plog, ctl->Scell_log,
-                     nla_data(tb[TCA_RED_STAB]),
+                     stab,
                      max_P);
        red_set_vars(&q->vars);
 

diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index 74f697c4a4d30209def45147cd6e7859b4b79cfe..1bfdf90fa0cce8d9d0bd28634fbf4bf24fc3817e 100644 (file)
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -651,7 +651,7 @@ static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
        }
 
        if (ctl_v1 && !red_check_params(ctl_v1->qth_min, ctl_v1->qth_max,
-                                       ctl_v1->Wlog, ctl_v1->Scell_log))
+                                       ctl_v1->Wlog, ctl_v1->Scell_log, NULL))
                return -EINVAL;
        if (ctl_v1 && ctl_v1->qth_min) {
                p = kmalloc(sizeof(*p), GFP_KERNEL);