On Wed, Sep 08, 2021 at 11:15:34AM +0100, Lee Jones wrote:
> From: Liu Jian <liujian56@xxxxxxxxxx>
>
> [ Upstream commit 23d2b94043ca8835bd1e67749020e839f396a1c2 ]
>
> I got below panic when doing fuzz test:
>
> Kernel panic - not syncing: panic_on_warn set ...
> CPU: 0 PID: 4056 Comm: syz-executor.3 Tainted: G B 5.14.0-rc1-00195-gcff5c4254439-dirty #2
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
> Call Trace:
> dump_stack_lvl+0x7a/0x9b
> panic+0x2cd/0x5af
> end_report.cold+0x5a/0x5a
> kasan_report+0xec/0x110
> ip_check_mc_rcu+0x556/0x5d0
> __mkroute_output+0x895/0x1740
> ip_route_output_key_hash_rcu+0x2d0/0x1050
> ip_route_output_key_hash+0x182/0x2e0
> ip_route_output_flow+0x28/0x130
> udp_sendmsg+0x165d/0x2280
> udpv6_sendmsg+0x121e/0x24f0
> inet6_sendmsg+0xf7/0x140
> sock_sendmsg+0xe9/0x180
> ____sys_sendmsg+0x2b8/0x7a0
> ___sys_sendmsg+0xf0/0x160
> __sys_sendmmsg+0x17e/0x3c0
> __x64_sys_sendmmsg+0x9e/0x100
> do_syscall_64+0x3b/0x90
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x462eb9
> Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 48 89 f8
> 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48>
> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f3df5af1c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
> RAX: ffffffffffffffda RBX: 000000000073bf00 RCX: 0000000000462eb9
> RDX: 0000000000000312 RSI: 0000000020001700 RDI: 0000000000000007
> RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3df5af26bc
> R13: 00000000004c372d R14: 0000000000700b10 R15: 00000000ffffffff
>
> It is one use-after-free in ip_check_mc_rcu.
> In ip_mc_del_src, the ip_sf_list of pmc has been freed under pmc->lock protection.
> But access to ip_sf_list in ip_check_mc_rcu is not protected by the lock.
>
> Cc: <stable@xxxxxxxxxxxxxxx> # 4.4+
> Signed-off-by: Liu Jian <liujian56@xxxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
> ---
> net/ipv4/igmp.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
> index 00576bae183d3..0c321996c6eb0 100644
> --- a/net/ipv4/igmp.c
> +++ b/net/ipv4/igmp.c
> @@ -2720,6 +2720,7 @@ int ip_check_mc_rcu(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u
> rv = 1;
> } else if (im) {
> if (src_addr) {
> + spin_lock_bh(&im->lock);
> for (psf = im->sources; psf; psf = psf->sf_next) {
> if (psf->sf_inaddr == src_addr)
> break;
> @@ -2730,6 +2731,7 @@ int ip_check_mc_rcu(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u
> im->sfcount[MCAST_EXCLUDE];
> else
> rv = im->sfcount[MCAST_EXCLUDE] != 0;
> + spin_unlock_bh(&im->lock);
> } else
> rv = 1; /* unspecified source; tentatively allow */
> }
> --
> 2.33.0.153.gba50c8fa24-goog
>
Now queued up, thanks.
greg k-h
