lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <1495654150.4297.11.camel@gmail.com> Date: Wed, 24 May 2017 12:29:10 -0700 From: Greg Rose <gvrose8192@...il.com> To: Alexander Potapenko <glider@...gle.com> Cc: dvyukov@...gle.com, kcc@...gle.com, edumazet@...gle.com, davem@...emloft.net, linux-kernel@...r.kernel.org, netdev@...r.kernel.org Subject: Re: [PATCH] net: rtnetlink: bail out from rtnl_fdb_dump() on parse error On Tue, 2017-05-23 at 13:20 +0200, Alexander Potapenko wrote: > rtnl_fdb_dump() failed to check the result of nlmsg_parse(), which led > to contents of |ifm| being uninitialized because nlh->nlmsglen was too > small to accommodate |ifm|. The uninitialized data may affect some > branches and result in unwanted effects, although kernel data doesn't > seem to leak to the userspace directly. > > The bug has been detected with KMSAN and syzkaller. > > Signed-off-by: Alexander Potapenko <glider@...gle.com> > --- > For the record, here is the KMSAN report: > > ================================================================== > BUG: KMSAN: use of unitialized memory in rtnl_fdb_dump+0x5dc/0x1000 > CPU: 0 PID: 1039 Comm: probe Not tainted 4.11.0-rc5+ #2727 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:16 > dump_stack+0x143/0x1b0 lib/dump_stack.c:52 > kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:1007 > __kmsan_warning_32+0x66/0xb0 mm/kmsan/kmsan_instr.c:491 > rtnl_fdb_dump+0x5dc/0x1000 net/core/rtnetlink.c:3230 > netlink_dump+0x84f/0x1190 net/netlink/af_netlink.c:2168 > __netlink_dump_start+0xc97/0xe50 net/netlink/af_netlink.c:2258 > netlink_dump_start ./include/linux/netlink.h:165 > rtnetlink_rcv_msg+0xae9/0xb40 net/core/rtnetlink.c:4094 > netlink_rcv_skb+0x339/0x5a0 net/netlink/af_netlink.c:2339 > rtnetlink_rcv+0x83/0xa0 net/core/rtnetlink.c:4110 > netlink_unicast_kernel net/netlink/af_netlink.c:1272 > netlink_unicast+0x13b7/0x1480 net/netlink/af_netlink.c:1298 > netlink_sendmsg+0x10b8/0x10f0 net/netlink/af_netlink.c:1844 > sock_sendmsg_nosec net/socket.c:633 > sock_sendmsg net/socket.c:643 > ___sys_sendmsg+0xd4b/0x10f0 net/socket.c:1997 > __sys_sendmsg net/socket.c:2031 > SYSC_sendmsg+0x2c6/0x3f0 net/socket.c:2042 > SyS_sendmsg+0x87/0xb0 net/socket.c:2038 > do_syscall_64+0x102/0x150 arch/x86/entry/common.c:285 > entry_SYSCALL64_slow_path+0x25/0x25 arch/x86/entry/entry_64.S:246 > RIP: 0033:0x401300 > RSP: 002b:00007ffc3b0e6d58 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 00000000004002b0 RCX: 0000000000401300 > RDX: 0000000000000000 RSI: 00007ffc3b0e6d80 RDI: 0000000000000003 > RBP: 00007ffc3b0e6e00 R08: 000000000000000b R09: 0000000000000004 > R10: 000000000000000d R11: 0000000000000246 R12: 0000000000000000 > R13: 00000000004065a0 R14: 0000000000406630 R15: 0000000000000000 > origin: 000000008fe00056 > save_stack_trace+0x59/0x60 arch/x86/kernel/stacktrace.c:59 > kmsan_save_stack_with_flags mm/kmsan/kmsan.c:352 > kmsan_internal_poison_shadow+0xb1/0x1a0 mm/kmsan/kmsan.c:247 > kmsan_poison_shadow+0x6d/0xc0 mm/kmsan/kmsan.c:260 > slab_alloc_node mm/slub.c:2743 > __kmalloc_node_track_caller+0x1f4/0x390 mm/slub.c:4349 > __kmalloc_reserve net/core/skbuff.c:138 > __alloc_skb+0x2cd/0x740 net/core/skbuff.c:231 > alloc_skb ./include/linux/skbuff.h:933 > netlink_alloc_large_skb net/netlink/af_netlink.c:1144 > netlink_sendmsg+0x934/0x10f0 net/netlink/af_netlink.c:1819 > sock_sendmsg_nosec net/socket.c:633 > sock_sendmsg net/socket.c:643 > ___sys_sendmsg+0xd4b/0x10f0 net/socket.c:1997 > __sys_sendmsg net/socket.c:2031 > SYSC_sendmsg+0x2c6/0x3f0 net/socket.c:2042 > SyS_sendmsg+0x87/0xb0 net/socket.c:2038 > do_syscall_64+0x102/0x150 arch/x86/entry/common.c:285 > return_from_SYSCALL_64+0x0/0x6a arch/x86/entry/entry_64.S:246 > ================================================================== > > and the reproducer: > > ================================================================== > #include <sys/socket.h> > #include <net/if_arp.h> > #include <linux/netlink.h> > #include <stdint.h> > > int main() > { > int sock = socket(PF_NETLINK, SOCK_DGRAM | SOCK_NONBLOCK, 0); > struct msghdr msg; > memset(&msg, 0, sizeof(msg)); > char nlmsg_buf[32]; > memset(nlmsg_buf, 0, sizeof(nlmsg_buf)); > struct nlmsghdr *nlmsg = nlmsg_buf; > nlmsg->nlmsg_len = 0x11; > nlmsg->nlmsg_type = 0x1e; // RTM_NEWROUTE = RTM_BASE + 0x0e > // type = 0x0e = 1110b > // kind = 2 > nlmsg->nlmsg_flags = 0x101; // NLM_F_ROOT | NLM_F_REQUEST > nlmsg->nlmsg_seq = 0; > nlmsg->nlmsg_pid = 0; > nlmsg_buf[16] = (char)7; > struct iovec iov; > iov.iov_base = nlmsg_buf; > iov.iov_len = 17; > msg.msg_iov = &iov; > msg.msg_iovlen = 1; > sendmsg(sock, &msg, 0); > return 0; > } > ================================================================== > --- > net/core/rtnetlink.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c > index 49a279a7cc15..9e2c0a7cb325 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -3231,8 +3231,11 @@ static int rtnl_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb) > int err = 0; > int fidx = 0; > > - if (nlmsg_parse(cb->nlh, sizeof(struct ifinfomsg), tb, > - IFLA_MAX, ifla_policy, NULL) == 0) { > + err = nlmsg_parse(cb->nlh, sizeof(struct ifinfomsg), tb, > + IFLA_MAX, ifla_policy, NULL); > + if (err < 0) { > + return -EINVAL; > + } else if (err == 0) { > if (tb[IFLA_MASTER]) > br_idx = nla_get_u32(tb[IFLA_MASTER]); > } Fix looks right to me. Reviewed-by: Greg Rose <gvrose8192@...il.com>
Powered by blists - more mailing lists