From 8ec9897ec2e93a412b9e3119e3137583a85969e0 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Fri, 10 May 2024 19:19:12 +0200 Subject: 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: 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 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: f6d8bd051c39 ("inet: add RCU protection to inet->opt") Reported-by: Xiumei Mu Signed-off-by: Davide Caratti Acked-by: Casey Schaufler Acked-by: Paul Moore Link: https://lore.kernel.org/r/f4260d000a3a55b9e8b6a3b4e3fffc7da9f82d41.1715359817.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski --- security/selinux/netlabel.c | 5 ++++- security/smack/smack_lsm.c | 3 ++- 2 files changed, 6 insertions(+), 2 deletions(-) (limited to 'security') diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c index 8f182800e412..55885634e880 100644 --- a/security/selinux/netlabel.c +++ b/security/selinux/netlabel.c @@ -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; diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 146667937811..efeac8365ad0 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -2565,7 +2565,8 @@ static int smack_netlbl_add(struct sock *sk) local_bh_disable(); bh_lock_sock_nested(sk); - rc = netlbl_sock_setattr(sk, sk->sk_family, &skp->smk_netlabel); + rc = netlbl_sock_setattr(sk, sk->sk_family, &skp->smk_netlabel, + netlbl_sk_lock_check(sk)); switch (rc) { case 0: ssp->smk_state = SMK_NETLBL_LABELED; -- cgit v1.2.3-58-ga151