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authorJulian Anastasov <ja@ssi.bg>2018-05-19 18:22:35 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-06-26 08:08:05 +0800
commit0063faaa86ddd392c7e870da911d1065a25be423 (patch)
treeb3546f9b143c6bd485b3ecd48d562f202fd7c089
parent8268afc568de4f84e2ea29640ea7229b32b47639 (diff)
ipvs: fix buffer overflow with sync daemon and service
[ Upstream commit 52f96757905bbf0edef47f3ee6c7c784e7f8ff8a ] syzkaller reports for buffer overflow for interface name when starting sync daemons [1] What we do is that we copy user structure into larger stack buffer but later we search NUL past the stack buffer. The same happens for sched_name when adding/editing virtual server. We are restricted by IP_VS_SCHEDNAME_MAXLEN and IP_VS_IFNAME_MAXLEN being used as size in include/uapi/linux/ip_vs.h, so they include the space for NUL. As using strlcpy is wrong for unsafe source, replace it with strscpy and add checks to return EINVAL if source string is not NUL-terminated. The incomplete strlcpy fix comes from 2.6.13. For the netlink interface reduce the len parameter for IPVS_DAEMON_ATTR_MCAST_IFN and IPVS_SVC_ATTR_SCHED_NAME, so that we get proper EINVAL. [1] kernel BUG at lib/string.c:1052! invalid opcode: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 373 Comm: syz-executor936 Not tainted 4.17.0-rc4+ #45 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:fortify_panic+0x13/0x20 lib/string.c:1051 RSP: 0018:ffff8801c976f800 EFLAGS: 00010282 RAX: 0000000000000022 RBX: 0000000000000040 RCX: 0000000000000000 RDX: 0000000000000022 RSI: ffffffff8160f6f1 RDI: ffffed00392edef6 RBP: ffff8801c976f800 R08: ffff8801cf4c62c0 R09: ffffed003b5e4fb0 R10: ffffed003b5e4fb0 R11: ffff8801daf27d87 R12: ffff8801c976fa20 R13: ffff8801c976fae4 R14: ffff8801c976fae0 R15: 000000000000048b FS: 00007fd99f75e700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200001c0 CR3: 00000001d6843000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: strlen include/linux/string.h:270 [inline] strlcpy include/linux/string.h:293 [inline] do_ip_vs_set_ctl+0x31c/0x1d00 net/netfilter/ipvs/ip_vs_ctl.c:2388 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x7d/0xd0 net/netfilter/nf_sockopt.c:115 ip_setsockopt+0xd8/0xf0 net/ipv4/ip_sockglue.c:1253 udp_setsockopt+0x62/0xa0 net/ipv4/udp.c:2487 ipv6_setsockopt+0x149/0x170 net/ipv6/ipv6_sockglue.c:917 tcp_setsockopt+0x93/0xe0 net/ipv4/tcp.c:3057 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:3046 __sys_setsockopt+0x1bd/0x390 net/socket.c:1903 __do_sys_setsockopt net/socket.c:1914 [inline] __se_sys_setsockopt net/socket.c:1911 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1911 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x447369 RSP: 002b:00007fd99f75dda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00000000006e39e4 RCX: 0000000000447369 RDX: 000000000000048b RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000018 R09: 0000000000000000 R10: 00000000200001c0 R11: 0000000000000246 R12: 00000000006e39e0 R13: 75a1ff93f0896195 R14: 6f745f3168746576 R15: 0000000000000001 Code: 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b 48 89 df e8 d2 8f 48 fa eb de 55 48 89 fe 48 c7 c7 60 65 64 88 48 89 e5 e8 91 dd f3 f9 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 56 RIP: fortify_panic+0x13/0x20 lib/string.c:1051 RSP: ffff8801c976f800 Reported-and-tested-by: syzbot+aac887f77319868646df@syzkaller.appspotmail.com Fixes: e4ff67513096 ("ipvs: add sync_maxlen parameter for the sync daemon") Fixes: 4da62fc70d7c ("[IPVS]: Fix for overflows") Signed-off-by: Julian Anastasov <ja@ssi.bg> Acked-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/netfilter/ipvs/ip_vs_ctl.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index c5f2350a2b50..079b3c426720 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2390,8 +2390,10 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
struct ipvs_sync_daemon_cfg cfg;
memset(&cfg, 0, sizeof(cfg));
- strlcpy(cfg.mcast_ifn, dm->mcast_ifn,
- sizeof(cfg.mcast_ifn));
+ ret = -EINVAL;
+ if (strscpy(cfg.mcast_ifn, dm->mcast_ifn,
+ sizeof(cfg.mcast_ifn)) <= 0)
+ goto out_dec;
cfg.syncid = dm->syncid;
ret = start_sync_thread(ipvs, &cfg, dm->state);
} else {
@@ -2429,12 +2431,19 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
}
}
+ if ((cmd == IP_VS_SO_SET_ADD || cmd == IP_VS_SO_SET_EDIT) &&
+ strnlen(usvc.sched_name, IP_VS_SCHEDNAME_MAXLEN) ==
+ IP_VS_SCHEDNAME_MAXLEN) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
/* Check for valid protocol: TCP or UDP or SCTP, even for fwmark!=0 */
if (usvc.protocol != IPPROTO_TCP && usvc.protocol != IPPROTO_UDP &&
usvc.protocol != IPPROTO_SCTP) {
- pr_err("set_ctl: invalid protocol: %d %pI4:%d %s\n",
+ pr_err("set_ctl: invalid protocol: %d %pI4:%d\n",
usvc.protocol, &usvc.addr.ip,
- ntohs(usvc.port), usvc.sched_name);
+ ntohs(usvc.port));
ret = -EFAULT;
goto out_unlock;
}
@@ -2863,7 +2872,7 @@ static const struct nla_policy ip_vs_cmd_policy[IPVS_CMD_ATTR_MAX + 1] = {
static const struct nla_policy ip_vs_daemon_policy[IPVS_DAEMON_ATTR_MAX + 1] = {
[IPVS_DAEMON_ATTR_STATE] = { .type = NLA_U32 },
[IPVS_DAEMON_ATTR_MCAST_IFN] = { .type = NLA_NUL_STRING,
- .len = IP_VS_IFNAME_MAXLEN },
+ .len = IP_VS_IFNAME_MAXLEN - 1 },
[IPVS_DAEMON_ATTR_SYNC_ID] = { .type = NLA_U32 },
[IPVS_DAEMON_ATTR_SYNC_MAXLEN] = { .type = NLA_U16 },
[IPVS_DAEMON_ATTR_MCAST_GROUP] = { .type = NLA_U32 },
@@ -2881,7 +2890,7 @@ static const struct nla_policy ip_vs_svc_policy[IPVS_SVC_ATTR_MAX + 1] = {
[IPVS_SVC_ATTR_PORT] = { .type = NLA_U16 },
[IPVS_SVC_ATTR_FWMARK] = { .type = NLA_U32 },
[IPVS_SVC_ATTR_SCHED_NAME] = { .type = NLA_NUL_STRING,
- .len = IP_VS_SCHEDNAME_MAXLEN },
+ .len = IP_VS_SCHEDNAME_MAXLEN - 1 },
[IPVS_SVC_ATTR_PE_NAME] = { .type = NLA_NUL_STRING,
.len = IP_VS_PENAME_MAXLEN },
[IPVS_SVC_ATTR_FLAGS] = { .type = NLA_BINARY,