[PATCH 4.16 12/48] ipmr: properly check rhltable_init() return value

From: Greg Kroah-Hartman
Date: Sat Jun 09 2018 - 11:31:55 EST

4.16-stable review patch. If anyone has any objections, please let me know.


From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit 66fb33254f45df4b049f487aff1cbde1ef919390 ]

commit 8fb472c09b9d ("ipmr: improve hash scalability")
added a call to rhltable_init() without checking its return value.

This problem was then later copied to IPv6 and factorized in commit
0bbbf0e7d0e7 ("ipmr, ip6mr: Unite creation of new mr_table")

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 31552 Comm: syz-executor7 Not tainted 4.17.0-rc5+ #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:rht_key_hashfn include/linux/rhashtable.h:277 [inline]
RIP: 0010:__rhashtable_lookup include/linux/rhashtable.h:630 [inline]
RIP: 0010:rhltable_lookup include/linux/rhashtable.h:716 [inline]
RIP: 0010:mr_mfc_find_parent+0x2ad/0xbb0 net/ipv4/ipmr_base.c:63
RSP: 0018:ffff8801826aef70 EFLAGS: 00010203
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffc90001ea0000
RDX: 0000000000000079 RSI: ffffffff8661e859 RDI: 000000000000000c
RBP: ffff8801826af1c0 R08: ffff8801b2212000 R09: ffffed003b5e46c2
R10: ffffed003b5e46c2 R11: ffff8801daf23613 R12: dffffc0000000000
R13: ffff8801826af198 R14: ffff8801cf8225c0 R15: ffff8801826af658
FS: 00007ff7fa732700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000003ffffff9c CR3: 00000001b0210000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ip6mr_cache_find_parent net/ipv6/ip6mr.c:981 [inline]
ip6mr_mfc_delete+0x1fe/0x6b0 net/ipv6/ip6mr.c:1221
ip6_mroute_setsockopt+0x15c6/0x1d70 net/ipv6/ip6mr.c:1698
do_ipv6_setsockopt.isra.9+0x422/0x4660 net/ipv6/ipv6_sockglue.c:163
ipv6_setsockopt+0xbd/0x170 net/ipv6/ipv6_sockglue.c:922
rawv6_setsockopt+0x59/0x140 net/ipv6/raw.c:1060
sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:3039
__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

Fixes: 8fb472c09b9d ("ipmr: improve hash scalability")
Fixes: 0bbbf0e7d0e7 ("ipmr, ip6mr: Unite creation of new mr_table")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>
Cc: Yuval Mintz <yuvalm@xxxxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/ipv4/ipmr.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -356,6 +356,7 @@ static const struct rhashtable_params ip
static struct mr_table *ipmr_new_table(struct net *net, u32 id)
struct mr_table *mrt;
+ int err;

/* "pimreg%u" should not exceed 16 bytes (IFNAMSIZ) */
if (id != RT_TABLE_DEFAULT && id >= 1000000000)
@@ -371,7 +372,11 @@ static struct mr_table *ipmr_new_table(s
write_pnet(&mrt->net, net);
mrt->id = id;

- rhltable_init(&mrt->mfc_hash, &ipmr_rht_params);
+ err = rhltable_init(&mrt->mfc_hash, &ipmr_rht_params);
+ if (err) {
+ kfree(mrt);
+ return ERR_PTR(err);
+ }