x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 309 insertions, 0 deletions

diff --git a/net/bluetooth/hidp/sock.c b/net/bluetooth/hidp/sock.c
new file mode 100644
index 000000000..b75bea3cf
--- /dev/null
+++ b/net/bluetooth/hidp/sock.c
@@ -0,0 +1,309 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+   HIDP implementation for Linux Bluetooth stack (BlueZ).
+   Copyright (C) 2003-2004 Marcel Holtmann <marcel@holtmann.org>
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
+   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
+   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
+   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
+   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
+   SOFTWARE IS DISCLAIMED.
+*/
+
+#include <linux/compat.h>
+#include <linux/export.h>
+#include <linux/file.h>
+
+#include "hidp.h"
+
+static struct bt_sock_list hidp_sk_list = {
+	.lock = __RW_LOCK_UNLOCKED(hidp_sk_list.lock)
+};
+
+static int hidp_sock_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+
+	BT_DBG("sock %p sk %p", sock, sk);
+
+	if (!sk)
+		return 0;
+
+	bt_sock_unlink(&hidp_sk_list, sk);
+
+	sock_orphan(sk);
+	sock_put(sk);
+
+	return 0;
+}
+
+static int do_hidp_sock_ioctl(struct socket *sock, unsigned int cmd, void __user *argp)
+{
+	struct hidp_connadd_req ca;
+	struct hidp_conndel_req cd;
+	struct hidp_connlist_req cl;
+	struct hidp_conninfo ci;
+	struct socket *csock;
+	struct socket *isock;
+	int err;
+
+	BT_DBG("cmd %x arg %p", cmd, argp);
+
+	switch (cmd) {
+	case HIDPCONNADD:
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		if (copy_from_user(&ca, argp, sizeof(ca)))
+			return -EFAULT;
+
+		csock = sockfd_lookup(ca.ctrl_sock, &err);
+		if (!csock)
+			return err;
+
+		isock = sockfd_lookup(ca.intr_sock, &err);
+		if (!isock) {
+			sockfd_put(csock);
+			return err;
+		}
+		ca.name[sizeof(ca.name)-1] = 0;
+
+		err = hidp_connection_add(&ca, csock, isock);
+		if (!err && copy_to_user(argp, &ca, sizeof(ca)))
+			err = -EFAULT;
+
+		sockfd_put(csock);
+		sockfd_put(isock);
+
+		return err;
+
+	case HIDPCONNDEL:
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		if (copy_from_user(&cd, argp, sizeof(cd)))
+			return -EFAULT;
+
+		return hidp_connection_del(&cd);
+
+	case HIDPGETCONNLIST:
+		if (copy_from_user(&cl, argp, sizeof(cl)))
+			return -EFAULT;
+
+		if (cl.cnum <= 0)
+			return -EINVAL;
+
+		err = hidp_get_connlist(&cl);
+		if (!err && copy_to_user(argp, &cl, sizeof(cl)))
+			return -EFAULT;
+
+		return err;
+
+	case HIDPGETCONNINFO:
+		if (copy_from_user(&ci, argp, sizeof(ci)))
+			return -EFAULT;
+
+		err = hidp_get_conninfo(&ci);
+		if (!err && copy_to_user(argp, &ci, sizeof(ci)))
+			return -EFAULT;
+
+		return err;
+	}
+
+	return -EINVAL;
+}
+
+static int hidp_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	return do_hidp_sock_ioctl(sock, cmd, (void __user *)arg);
+}
+
+#ifdef CONFIG_COMPAT
+struct compat_hidp_connadd_req {
+	int   ctrl_sock;	/* Connected control socket */
+	int   intr_sock;	/* Connected interrupt socket */
+	__u16 parser;
+	__u16 rd_size;
+	compat_uptr_t rd_data;
+	__u8  country;
+	__u8  subclass;
+	__u16 vendor;
+	__u16 product;
+	__u16 version;
+	__u32 flags;
+	__u32 idle_to;
+	char  name[128];
+};
+
+static int hidp_sock_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = compat_ptr(arg);
+	int err;
+
+	if (cmd == HIDPGETCONNLIST) {
+		struct hidp_connlist_req cl;
+		u32 __user *p = argp;
+		u32 uci;
+
+		if (get_user(cl.cnum, p) || get_user(uci, p + 1))
+			return -EFAULT;
+
+		cl.ci = compat_ptr(uci);
+
+		if (cl.cnum <= 0)
+			return -EINVAL;
+
+		err = hidp_get_connlist(&cl);
+
+		if (!err && put_user(cl.cnum, p))
+			err = -EFAULT;
+
+		return err;
+	} else if (cmd == HIDPCONNADD) {
+		struct compat_hidp_connadd_req ca32;
+		struct hidp_connadd_req ca;
+		struct socket *csock;
+		struct socket *isock;
+
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		if (copy_from_user(&ca32, (void __user *) arg, sizeof(ca32)))
+			return -EFAULT;
+
+		ca.ctrl_sock = ca32.ctrl_sock;
+		ca.intr_sock = ca32.intr_sock;
+		ca.parser = ca32.parser;
+		ca.rd_size = ca32.rd_size;
+		ca.rd_data = compat_ptr(ca32.rd_data);
+		ca.country = ca32.country;
+		ca.subclass = ca32.subclass;
+		ca.vendor = ca32.vendor;
+		ca.product = ca32.product;
+		ca.version = ca32.version;
+		ca.flags = ca32.flags;
+		ca.idle_to = ca32.idle_to;
+		ca32.name[sizeof(ca32.name) - 1] = '\0';
+		memcpy(ca.name, ca32.name, 128);
+
+		csock = sockfd_lookup(ca.ctrl_sock, &err);
+		if (!csock)
+			return err;
+
+		isock = sockfd_lookup(ca.intr_sock, &err);
+		if (!isock) {
+			sockfd_put(csock);
+			return err;
+		}
+
+		err = hidp_connection_add(&ca, csock, isock);
+		if (!err && copy_to_user(argp, &ca32, sizeof(ca32)))
+			err = -EFAULT;
+
+		sockfd_put(csock);
+		sockfd_put(isock);
+
+		return err;
+	}
+
+	return hidp_sock_ioctl(sock, cmd, arg);
+}
+#endif
+
+static const struct proto_ops hidp_sock_ops = {
+	.family		= PF_BLUETOOTH,
+	.owner		= THIS_MODULE,
+	.release	= hidp_sock_release,
+	.ioctl		= hidp_sock_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= hidp_sock_compat_ioctl,
+#endif
+	.bind		= sock_no_bind,
+	.getname	= sock_no_getname,
+	.sendmsg	= sock_no_sendmsg,
+	.recvmsg	= sock_no_recvmsg,
+	.listen		= sock_no_listen,
+	.shutdown	= sock_no_shutdown,
+	.connect	= sock_no_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= sock_no_accept,
+	.mmap		= sock_no_mmap
+};
+
+static struct proto hidp_proto = {
+	.name		= "HIDP",
+	.owner		= THIS_MODULE,
+	.obj_size	= sizeof(struct bt_sock)
+};
+
+static int hidp_sock_create(struct net *net, struct socket *sock, int protocol,
+			    int kern)
+{
+	struct sock *sk;
+
+	BT_DBG("sock %p", sock);
+
+	if (sock->type != SOCK_RAW)
+		return -ESOCKTNOSUPPORT;
+
+	sk = bt_sock_alloc(net, sock, &hidp_proto, protocol, GFP_ATOMIC, kern);
+	if (!sk)
+		return -ENOMEM;
+
+	sock->ops = &hidp_sock_ops;
+	sock->state = SS_UNCONNECTED;
+
+	bt_sock_link(&hidp_sk_list, sk);
+
+	return 0;
+}
+
+static const struct net_proto_family hidp_sock_family_ops = {
+	.family	= PF_BLUETOOTH,
+	.owner	= THIS_MODULE,
+	.create	= hidp_sock_create
+};
+
+int __init hidp_init_sockets(void)
+{
+	int err;
+
+	err = proto_register(&hidp_proto, 0);
+	if (err < 0)
+		return err;
+
+	err = bt_sock_register(BTPROTO_HIDP, &hidp_sock_family_ops);
+	if (err < 0) {
+		BT_ERR("Can't register HIDP socket");
+		goto error;
+	}
+
+	err = bt_procfs_init(&init_net, "hidp", &hidp_sk_list, NULL);
+	if (err < 0) {
+		BT_ERR("Failed to create HIDP proc file");
+		bt_sock_unregister(BTPROTO_HIDP);
+		goto error;
+	}
+
+	BT_INFO("HIDP socket layer initialized");
+
+	return 0;
+
+error:
+	proto_unregister(&hidp_proto);
+	return err;
+}
+
+void __exit hidp_cleanup_sockets(void)
+{
+	bt_procfs_cleanup(&init_net, "hidp");
+	bt_sock_unregister(BTPROTO_HIDP);
+	proto_unregister(&hidp_proto);
+}