Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Hawkins Jiawei <yin31149@gmail.com>
To:     syzbot+232ebdbd36706c965ebf@syzkaller.appspotmail.com,
        Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Jiri Pirko <jiri@resnulli.us>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     18801353760@163.com, johannes@sipsolutions.net,
        linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
        netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com,
        yin31149@gmail.com
Subject: Re: [syzbot] memory leak in regulatory_hint_core
Date:   Sun, 30 Oct 2022 23:36:23 +0800
Message-Id: <20221030153622.22720-1-yin31149@gmail.com>
In-Reply-To: <0000000000007fa5c805ec39f00a@google.com>
References: <0000000000007fa5c805ec39f00a@google.com>
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On Sun, 30 Oct 2022 at 00:14, Hawkins Jiawei <yin31149@gmail.com> wrote:
>
> Hi,
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    aae703b02f92 Merge tag 'for-6.1-rc1-tag' of git://git.kern..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=113ed1b4880000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=d2f454d7d3b63980
> > dashboard link: https://syzkaller.appspot.com/bug?extid=232ebdbd36706c965ebf
> > compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=124b8de2880000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12ae6a4a880000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/a6542869e73f/disk-aae703b0.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/1a8ac40b2df8/vmlinux-aae703b0.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+232ebdbd36706c965ebf@syzkaller.appspotmail.com
> >
> > executing program
> > BUG: memory leak
> > unreferenced object 0xffff8881450a3900 (size 64):
> >   comm "swapper/0", pid 1, jiffies 4294937964 (age 66.260s)
> >   hex dump (first 32 bytes):
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >     ff ff ff ff 00 00 00 00 00 00 00 00 30 30 00 00  ............00..
> >   backtrace:
> >     [<ffffffff814cf9f0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
> >     [<ffffffff84070f62>] kmalloc include/linux/slab.h:576 [inline]
> >     [<ffffffff84070f62>] kzalloc include/linux/slab.h:712 [inline]
> >     [<ffffffff84070f62>] regulatory_hint_core+0x22/0x60 net/wireless/reg.c:3242
> >     [<ffffffff8722bfc1>] regulatory_init_db+0x222/0x2de net/wireless/reg.c:4312
> >     [<ffffffff81000fde>] do_one_initcall+0x5e/0x2e0 init/main.c:1303
> >     [<ffffffff8718db35>] do_initcall_level init/main.c:1376 [inline]
> >     [<ffffffff8718db35>] do_initcalls init/main.c:1392 [inline]
> >     [<ffffffff8718db35>] do_basic_setup init/main.c:1411 [inline]
> >     [<ffffffff8718db35>] kernel_init_freeable+0x255/0x2cf init/main.c:1631
> >     [<ffffffff8460cb9a>] kernel_init+0x1a/0x1c0 init/main.c:1519
> >     [<ffffffff8100224f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
> >
> > BUG: memory leak
> > unreferenced object 0xffff88810c287f00 (size 256):
> >   comm "syz-executor105", pid 3600, jiffies 4294943292 (age 12.990s)
> >   hex dump (first 32 bytes):
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >   backtrace:
> >     [<ffffffff814cf9f0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
> >     [<ffffffff839c9e07>] kmalloc include/linux/slab.h:576 [inline]
> >     [<ffffffff839c9e07>] kmalloc_array include/linux/slab.h:627 [inline]
> >     [<ffffffff839c9e07>] kcalloc include/linux/slab.h:659 [inline]
> >     [<ffffffff839c9e07>] tcf_exts_init include/net/pkt_cls.h:250 [inline]
> >     [<ffffffff839c9e07>] tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342
> >     [<ffffffff839caa1f>] tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553
> >     [<ffffffff8394db62>] tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147
> >     [<ffffffff8389e91c>] rtnetlink_rcv_msg+0x4dc/0x5d0 net/core/rtnetlink.c:6082
> >     [<ffffffff839eba67>] netlink_rcv_skb+0x87/0x1d0 net/netlink/af_netlink.c:2540
> >     [<ffffffff839eab87>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
> >     [<ffffffff839eab87>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345
> >     [<ffffffff839eb046>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921
> >     [<ffffffff8383e796>] sock_sendmsg_nosec net/socket.c:714 [inline]
> >     [<ffffffff8383e796>] sock_sendmsg+0x56/0x80 net/socket.c:734
> >     [<ffffffff8383eb08>] ____sys_sendmsg+0x178/0x410 net/socket.c:2482
> >     [<ffffffff83843678>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536
> >     [<ffffffff838439c5>] __sys_sendmmsg+0x105/0x330 net/socket.c:2622
> >     [<ffffffff83843c14>] __do_sys_sendmmsg net/socket.c:2651 [inline]
> >     [<ffffffff83843c14>] __se_sys_sendmmsg net/socket.c:2648 [inline]
> >     [<ffffffff83843c14>] __x64_sys_sendmmsg+0x24/0x30 net/socket.c:2648
> >     [<ffffffff84605fd5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> >     [<ffffffff84605fd5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> >     [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >
> > BUG: memory leak
> > unreferenced object 0xffff88810c287e00 (size 256):
> >   comm "syz-executor105", pid 3600, jiffies 4294943292 (age 12.990s)
> >   hex dump (first 32 bytes):
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >   backtrace:
> >     [<ffffffff814cf9f0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
> >     [<ffffffff839c9e07>] kmalloc include/linux/slab.h:576 [inline]
> >     [<ffffffff839c9e07>] kmalloc_array include/linux/slab.h:627 [inline]
> >     [<ffffffff839c9e07>] kcalloc include/linux/slab.h:659 [inline]
> >     [<ffffffff839c9e07>] tcf_exts_init include/net/pkt_cls.h:250 [inline]
> >     [<ffffffff839c9e07>] tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342
> >     [<ffffffff839caa1f>] tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553
> >     [<ffffffff8394db62>] tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147
> >     [<ffffffff8389e91c>] rtnetlink_rcv_msg+0x4dc/0x5d0 net/core/rtnetlink.c:6082
> >     [<ffffffff839eba67>] netlink_rcv_skb+0x87/0x1d0 net/netlink/af_netlink.c:2540
> >     [<ffffffff839eab87>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
> >     [<ffffffff839eab87>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345
> >     [<ffffffff839eb046>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921
> >     [<ffffffff8383e796>] sock_sendmsg_nosec net/socket.c:714 [inline]
> >     [<ffffffff8383e796>] sock_sendmsg+0x56/0x80 net/socket.c:734
> >     [<ffffffff8383eb08>] ____sys_sendmsg+0x178/0x410 net/socket.c:2482
> >     [<ffffffff83843678>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536
> >     [<ffffffff838439c5>] __sys_sendmmsg+0x105/0x330 net/socket.c:2622
> >     [<ffffffff83843c14>] __do_sys_sendmmsg net/socket.c:2651 [inline]
> >     [<ffffffff83843c14>] __se_sys_sendmmsg net/socket.c:2648 [inline]
> >     [<ffffffff83843c14>] __x64_sys_sendmmsg+0x24/0x30 net/socket.c:2648
> >     [<ffffffff84605fd5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> >     [<ffffffff84605fd5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> >     [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >
> > BUG: memory leak
> > unreferenced object 0xffff88810c1c6d00 (size 256):
> >   comm "syz-executor105", pid 3601, jiffies 4294943831 (age 7.600s)
> >   hex dump (first 32 bytes):
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >   backtrace:
> >     [<ffffffff814cf9f0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
> >     [<ffffffff839c9e07>] kmalloc include/linux/slab.h:576 [inline]
> >     [<ffffffff839c9e07>] kmalloc_array include/linux/slab.h:627 [inline]
> >     [<ffffffff839c9e07>] kcalloc include/linux/slab.h:659 [inline]
> >     [<ffffffff839c9e07>] tcf_exts_init include/net/pkt_cls.h:250 [inline]
> >     [<ffffffff839c9e07>] tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342
> >     [<ffffffff839caa1f>] tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553
> >     [<ffffffff8394db62>] tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147
> >     [<ffffffff8389e91c>] rtnetlink_rcv_msg+0x4dc/0x5d0 net/core/rtnetlink.c:6082
> >     [<ffffffff839eba67>] netlink_rcv_skb+0x87/0x1d0 net/netlink/af_netlink.c:2540
> >     [<ffffffff839eab87>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
> >     [<ffffffff839eab87>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345
> >     [<ffffffff839eb046>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921
> >     [<ffffffff8383e796>] sock_sendmsg_nosec net/socket.c:714 [inline]
> >     [<ffffffff8383e796>] sock_sendmsg+0x56/0x80 net/socket.c:734
> >     [<ffffffff8383eb08>] ____sys_sendmsg+0x178/0x410 net/socket.c:2482
> >     [<ffffffff83843678>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536
> >     [<ffffffff838439c5>] __sys_sendmmsg+0x105/0x330 net/socket.c:2622
> >     [<ffffffff83843c14>] __do_sys_sendmmsg net/socket.c:2651 [inline]
> >     [<ffffffff83843c14>] __se_sys_sendmmsg net/socket.c:2648 [inline]
> >     [<ffffffff83843c14>] __x64_sys_sendmmsg+0x24/0x30 net/socket.c:2648
> >     [<ffffffff84605fd5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> >     [<ffffffff84605fd5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> >     [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> This bug seems to be related to tcindex_set_parms().
>
> To be more specific, kernel should release the old_r->exts before
> initializing it. Let us test it.
Test if we need to release the old_r->exts after RCU assign.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
aae703b02f92bde9264366c545e87cec451de471

diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index 1c9eeb98d826..1c0bee2544d9 100644
--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -338,6 +338,9 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 	struct tcf_result cr = {};
 	int err, balloc = 0;
 	struct tcf_exts e;
+#ifdef CONFIG_NET_CLS_ACT
+	struct tcf_exts old_e = {};
+#endif
 
 	err = tcf_exts_init(&e, net, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
 	if (err < 0)
@@ -479,6 +482,14 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 	}
 
 	if (old_r && old_r != r) {
+#ifdef CONFIG_NET_CLS_ACT
+		/* r->exts is not copied from old_r->exts, and
+		 * the following code will clears the old_r, so
+		 * we need to destroy it after update the tp->root,
+		 * to avoid memory leak bug.
+		 */
+		old_e = old_r->exts;
+#endif
 		err = tcindex_filter_result_init(old_r, cp, net);
 		if (err < 0) {
 			kfree(f);
@@ -510,6 +521,9 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 		tcf_exts_destroy(&new_filter_result.exts);
 	}
 
+#ifdef CONFIG_NET_CLS_ACT
+	tcf_exts_destroy(&old_e);
+#endif
 	if (oldp)
 		tcf_queue_work(&oldp->rwork, tcindex_partial_destroy_work);
 	return 0;