From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hoeun Ryu Date: Sun, 19 Feb 2017 19:04:07 +0900 Message-Id: <1487498660-16600-4-git-send-email-hoeun.ryu@gmail.com> In-Reply-To: <1487498660-16600-1-git-send-email-hoeun.ryu@gmail.com> References: <1487498660-16600-1-git-send-email-hoeun.ryu@gmail.com> Subject: [kernel-hardening] [RFC 4/7] selinux: mark __ro_mostly_after_init for selinux_hooks/selinux_nf_ops To: kernel-hardening@lists.openwall.com, linux-kernel@vger.kernel.org Cc: Hoeun Ryu , Paul Moore , Stephen Smalley , Eric Paris , James Morris , "Serge E. Hallyn" , selinux@tycho.nsa.gov, linux-security-module@vger.kernel.org List-ID: It would be good that selinux hooks objects are marked as `__ro_mostly_after_init`. They can not be simply marked as `__ro_after_init' because they should be writable during selinux_disable procedure. `__ro_mostly_after_init` section is temporarily read-write during selinux_disable procedure via set_ro_mostly_after_init_rw/ro pair. Now that they can be read-only except during the procedure. Signed-off-by: Hoeun Ryu --- security/selinux/hooks.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 9a8f12f..64fd799 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -6106,7 +6106,7 @@ static int selinux_key_getsecurity(struct key *key, char **_buffer) #endif -static struct security_hook_list selinux_hooks[] = { +static struct security_hook_list selinux_hooks[] __ro_mostly_after_init = { LSM_HOOK_INIT(binder_set_context_mgr, selinux_binder_set_context_mgr), LSM_HOOK_INIT(binder_transaction, selinux_binder_transaction), LSM_HOOK_INIT(binder_transfer_binder, selinux_binder_transfer_binder), @@ -6381,7 +6381,7 @@ security_initcall(selinux_init); #if defined(CONFIG_NETFILTER) -static struct nf_hook_ops selinux_nf_ops[] = { +static struct nf_hook_ops selinux_nf_ops[] __ro_mostly_after_init = { { .hook = selinux_ipv4_postroute, .pf = NFPROTO_IPV4, @@ -6477,13 +6477,17 @@ int selinux_disable(void) selinux_disabled = 1; selinux_enabled = 0; + set_ro_mostly_after_init_rw(); security_delete_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks)); + set_ro_mostly_after_init_ro(); /* Try to destroy the avc node cache */ avc_disable(); /* Unregister netfilter hooks. */ + set_ro_mostly_after_init_ro(); selinux_nf_ip_exit(); + set_ro_mostly_after_init_rw(); /* Unregister selinuxfs. */ exit_sel_fs(); -- 2.7.4