Commit 8ec9897e authored by Davide Caratti's avatar Davide Caratti Committed by Jakub Kicinski
Browse files

netlabel: fix RCU annotation for IPv4 options on socket creation 



Xiumei reports the following splat when netlabel and TCP socket are used:

 =============================
 WARNING: suspicious RCU usage
 6.9.0-rc2+ #637 Not tainted
 -----------------------------
 net/ipv4/cipso_ipv4.c:1880 suspicious rcu_dereference_protected() usage!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 1 lock held by ncat/23333:
  #0: ffffffff906030c0 (rcu_read_lock){....}-{1:2}, at: netlbl_sock_setattr+0x25/0x1b0

 stack backtrace:
 CPU: 11 PID: 23333 Comm: ncat Kdump: loaded Not tainted 6.9.0-rc2+ #637
 Hardware name: Supermicro SYS-6027R-72RF/X9DRH-7TF/7F/iTF/iF, BIOS 3.0  07/26/2013
 Call Trace:
  <TASK>
  dump_stack_lvl+0xa9/0xc0
  lockdep_rcu_suspicious+0x117/0x190
  cipso_v4_sock_setattr+0x1ab/0x1b0
  netlbl_sock_setattr+0x13e/0x1b0
  selinux_netlbl_socket_post_create+0x3f/0x80
  selinux_socket_post_create+0x1a0/0x460
  security_socket_post_create+0x42/0x60
  __sock_create+0x342/0x3a0
  __sys_socket_create.part.22+0x42/0x70
  __sys_socket+0x37/0xb0
  __x64_sys_socket+0x16/0x20
  do_syscall_64+0x96/0x180
  ? do_user_addr_fault+0x68d/0xa30
  ? exc_page_fault+0x171/0x280
  ? asm_exc_page_fault+0x22/0x30
  entry_SYSCALL_64_after_hwframe+0x71/0x79
 RIP: 0033:0x7fbc0ca3fc1b
 Code: 73 01 c3 48 8b 0d 05 f2 1b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d d5 f1 1b 00 f7 d8 64 89 01 48
 RSP: 002b:00007fff18635208 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fbc0ca3fc1b
 RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002
 RBP: 000055d24f80f8a0 R08: 0000000000000003 R09: 0000000000000001

R10: 0000000000020000 R11: 0000000000000246 R12: 000055d24f80f8a0
 R13: 0000000000000000 R14: 000055d24f80fb88 R15: 0000000000000000
  </TASK>

The current implementation of cipso_v4_sock_setattr() replaces IP options
under the assumption that the caller holds the socket lock; however, such
assumption is not true, nor needed, in selinux_socket_post_create() hook.

Let all callers of cipso_v4_sock_setattr() specify the "socket lock held"
condition, except selinux_socket_post_create() _ where such condition can
safely be set as true even without holding the socket lock.

Fixes: f6d8bd05 ("inet: add RCU protection to inet->opt")
Reported-by: default avatarXiumei Mu <xmu@redhat.com>
Signed-off-by: default avatarDavide Caratti <dcaratti@redhat.com>
Acked-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
Acked-by: default avatarPaul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/f4260d000a3a55b9e8b6a3b4e3fffc7da9f82d41.1715359817.git.dcaratti@redhat.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1af7f88a

include/net/cipso_ipv4.h

+4 −2
Original line number Diff line number Diff line
@@ -183,7 +183,8 @@ int cipso_v4_getattr(const unsigned char *cipso, 
		     struct netlbl_lsm_secattr *secattr);

int cipso_v4_sock_setattr(struct sock *sk,

			  const struct cipso_v4_doi *doi_def,

			  const struct netlbl_lsm_secattr *secattr);

			  const struct netlbl_lsm_secattr *secattr,

			  bool sk_locked);

void cipso_v4_sock_delattr(struct sock *sk);

int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr);

int cipso_v4_req_setattr(struct request_sock *req,
@@ -214,7 +215,8 @@ static inline int cipso_v4_getattr(const unsigned char *cipso, 


static inline int cipso_v4_sock_setattr(struct sock *sk,

				      const struct cipso_v4_doi *doi_def,

				      const struct netlbl_lsm_secattr *secattr)

				      const struct netlbl_lsm_secattr *secattr,

				      bool sk_locked)

{

	return -ENOSYS;

}

include/net/netlabel.h

+10 −2
Original line number Diff line number Diff line
@@ -470,7 +470,8 @@ void netlbl_bitmap_setbit(unsigned char *bitmap, u32 bit, u8 state); 
int netlbl_enabled(void);

int netlbl_sock_setattr(struct sock *sk,

			u16 family,

			const struct netlbl_lsm_secattr *secattr);

			const struct netlbl_lsm_secattr *secattr,

			bool sk_locked);

void netlbl_sock_delattr(struct sock *sk);

int netlbl_sock_getattr(struct sock *sk,

			struct netlbl_lsm_secattr *secattr);
@@ -487,6 +488,7 @@ int netlbl_skbuff_getattr(const struct sk_buff *skb, 
			  u16 family,

			  struct netlbl_lsm_secattr *secattr);

void netlbl_skbuff_err(struct sk_buff *skb, u16 family, int error, int gateway);

bool netlbl_sk_lock_check(struct sock *sk);



/*

 * LSM label mapping cache operations
@@ -614,7 +616,8 @@ static inline int netlbl_enabled(void) 
}

static inline int netlbl_sock_setattr(struct sock *sk,

				      u16 family,

				      const struct netlbl_lsm_secattr *secattr)

				      const struct netlbl_lsm_secattr *secattr,

				      bool sk_locked)

{

	return -ENOSYS;

}
@@ -673,6 +676,11 @@ static inline struct audit_buffer *netlbl_audit_start(int type, 
{

	return NULL;

}



static inline bool netlbl_sk_lock_check(struct sock *sk)

{

	return true;

}

#endif /* CONFIG_NETLABEL */



const struct netlbl_calipso_ops *

net/ipv4/cipso_ipv4.c

+4 −3
Original line number Diff line number Diff line
@@ -1815,6 +1815,7 @@ static int cipso_v4_genopt(unsigned char *buf, u32 buf_len, 
 * @sk: the socket

 * @doi_def: the CIPSO DOI to use

 * @secattr: the specific security attributes of the socket

 * @sk_locked: true if caller holds the socket lock

 *

 * Description:

 * Set the CIPSO option on the given socket using the DOI definition and
@@ -1826,7 +1827,8 @@ static int cipso_v4_genopt(unsigned char *buf, u32 buf_len, 
 */

int cipso_v4_sock_setattr(struct sock *sk,

			  const struct cipso_v4_doi *doi_def,

			  const struct netlbl_lsm_secattr *secattr)

			  const struct netlbl_lsm_secattr *secattr,

			  bool sk_locked)

{

	int ret_val = -EPERM;

	unsigned char *buf = NULL;
@@ -1876,8 +1878,7 @@ int cipso_v4_sock_setattr(struct sock *sk, 


	sk_inet = inet_sk(sk);



	old = rcu_dereference_protected(sk_inet->inet_opt,

					lockdep_sock_is_held(sk));

	old = rcu_dereference_protected(sk_inet->inet_opt, sk_locked);

	if (inet_test_bit(IS_ICSK, sk)) {

		sk_conn = inet_csk(sk);

		if (old)

net/netlabel/netlabel_kapi.c

+28 −3
Original line number Diff line number Diff line
@@ -965,6 +965,7 @@ int netlbl_enabled(void) 
 * @sk: the socket to label

 * @family: protocol family

 * @secattr: the security attributes

 * @sk_locked: true if caller holds the socket lock

 *

 * Description:

 * Attach the correct label to the given socket using the security attributes
@@ -977,7 +978,8 @@ int netlbl_enabled(void) 
 */

int netlbl_sock_setattr(struct sock *sk,

			u16 family,

			const struct netlbl_lsm_secattr *secattr)

			const struct netlbl_lsm_secattr *secattr,

			bool sk_locked)

{

	int ret_val;

	struct netlbl_dom_map *dom_entry;
@@ -997,7 +999,7 @@ int netlbl_sock_setattr(struct sock *sk, 
		case NETLBL_NLTYPE_CIPSOV4:

			ret_val = cipso_v4_sock_setattr(sk,

							dom_entry->def.cipso,

							secattr);

							secattr, sk_locked);

			break;

		case NETLBL_NLTYPE_UNLABELED:

			ret_val = 0;
@@ -1090,6 +1092,28 @@ int netlbl_sock_getattr(struct sock *sk, 
	return ret_val;

}



/**

 * netlbl_sk_lock_check - Check if the socket lock has been acquired.

 * @sk: the socket to be checked

 *

 * Return: true if socket @sk is locked or if lock debugging is disabled at

 * runtime or compile-time; false otherwise

 *

 */

#ifdef CONFIG_LOCKDEP

bool netlbl_sk_lock_check(struct sock *sk)

{

	if (debug_locks)

		return lockdep_sock_is_held(sk);

	return true;

}

#else

bool netlbl_sk_lock_check(struct sock *sk)

{

	return true;

}

#endif



/**

 * netlbl_conn_setattr - Label a connected socket using the correct protocol

 * @sk: the socket to label
@@ -1126,7 +1150,8 @@ int netlbl_conn_setattr(struct sock *sk, 
		switch (entry->type) {

		case NETLBL_NLTYPE_CIPSOV4:

			ret_val = cipso_v4_sock_setattr(sk,

							entry->cipso, secattr);

							entry->cipso, secattr,

							netlbl_sk_lock_check(sk));

			break;

		case NETLBL_NLTYPE_UNLABELED:

			/* just delete the protocols we support for right now

security/selinux/netlabel.c

+4 −1
Original line number Diff line number Diff line
@@ -402,7 +402,10 @@ int selinux_netlbl_socket_post_create(struct sock *sk, u16 family) 
	secattr = selinux_netlbl_sock_genattr(sk);

	if (secattr == NULL)

		return -ENOMEM;

	rc = netlbl_sock_setattr(sk, family, secattr);

	/* On socket creation, replacement of IP options is safe even if

	 * the caller does not hold the socket lock.

	 */

	rc = netlbl_sock_setattr(sk, family, secattr, true);

	switch (rc) {

	case 0:

		sksec->nlbl_state = NLBL_LABELED;