From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:44135 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391928AbeIVGKp (ORCPT ); Sat, 22 Sep 2018 02:10:45 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Andy Lutomirski" , "Oleg Nesterov" , "Kees Cook" Date: Sat, 22 Sep 2018 01:15:42 +0100 Message-ID: Subject: [PATCH 3.16 56/63] seccomp: split mode setting routines In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: 3.16.58-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit 3b23dd12846215eff4afb073366b80c0c4d7543e upstream. Separates the two mode setting paths to make things more readable with fewer #ifdefs within function bodies. Signed-off-by: Kees Cook Reviewed-by: Oleg Nesterov Reviewed-by: Andy Lutomirski Signed-off-by: Ben Hutchings --- kernel/seccomp.c | 71 ++++++++++++++++++++++++++++++++---------------- 1 file changed, 48 insertions(+), 23 deletions(-) --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -489,48 +489,66 @@ long prctl_get_seccomp(void) } /** - * seccomp_set_mode: internal function for setting seccomp mode - * @seccomp_mode: requested mode to use - * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER - * - * This function may be called repeatedly with a @seccomp_mode of - * SECCOMP_MODE_FILTER to install additional filters. Every filter - * successfully installed will be evaluated (in reverse order) for each system - * call the task makes. + * seccomp_set_mode_strict: internal function for setting strict seccomp * * Once current->seccomp.mode is non-zero, it may not be changed. * * Returns 0 on success or -EINVAL on failure. */ -static long seccomp_set_mode(unsigned long seccomp_mode, char __user *filter) +static long seccomp_set_mode_strict(void) { + const unsigned long seccomp_mode = SECCOMP_MODE_STRICT; long ret = -EINVAL; if (!seccomp_may_assign_mode(seccomp_mode)) goto out; - switch (seccomp_mode) { - case SECCOMP_MODE_STRICT: - ret = 0; #ifdef TIF_NOTSC - disable_TSC(); + disable_TSC(); #endif - break; + seccomp_assign_mode(seccomp_mode); + ret = 0; + +out: + + return ret; +} + #ifdef CONFIG_SECCOMP_FILTER - case SECCOMP_MODE_FILTER: - ret = seccomp_attach_user_filter(filter); - if (ret) - goto out; - break; -#endif - default: +/** + * seccomp_set_mode_filter: internal function for setting seccomp filter + * @filter: struct sock_fprog containing filter + * + * This function may be called repeatedly to install additional filters. + * Every filter successfully installed will be evaluated (in reverse order) + * for each system call the task makes. + * + * Once current->seccomp.mode is non-zero, it may not be changed. + * + * Returns 0 on success or -EINVAL on failure. + */ +static long seccomp_set_mode_filter(char __user *filter) +{ + const unsigned long seccomp_mode = SECCOMP_MODE_FILTER; + long ret = -EINVAL; + + if (!seccomp_may_assign_mode(seccomp_mode)) + goto out; + + ret = seccomp_attach_user_filter(filter); + if (ret) goto out; - } seccomp_assign_mode(seccomp_mode); out: return ret; } +#else +static inline long seccomp_set_mode_filter(char __user *filter) +{ + return -EINVAL; +} +#endif /** * prctl_set_seccomp: configures current->seccomp.mode @@ -541,5 +559,12 @@ out: */ long prctl_set_seccomp(unsigned long seccomp_mode, char __user *filter) { - return seccomp_set_mode(seccomp_mode, filter); + switch (seccomp_mode) { + case SECCOMP_MODE_STRICT: + return seccomp_set_mode_strict(); + case SECCOMP_MODE_FILTER: + return seccomp_set_mode_filter(filter); + default: + return -EINVAL; + } }