diff options
| -rw-r--r-- | include/linux/pid_namespace.h | 23 | ||||
| -rw-r--r-- | kernel/pid.c | 3 | ||||
| -rw-r--r-- | kernel/pid_namespace.c | 6 | ||||
| -rw-r--r-- | kernel/pid_sysctl.h | 28 | ||||
| -rw-r--r-- | mm/memfd.c | 3 |
5 files changed, 42 insertions, 21 deletions
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index 53974d79d98e..f9f9931e02d6 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -39,7 +39,6 @@ struct pid_namespace { int reboot; /* group exit code if this pidns was rebooted */ struct ns_common ns; #if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE) - /* sysctl for vm.memfd_noexec */ int memfd_noexec_scope; #endif } __randomize_layout; @@ -56,6 +55,23 @@ static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns) return ns; } +#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE) +static inline int pidns_memfd_noexec_scope(struct pid_namespace *ns) +{ + int scope = MEMFD_NOEXEC_SCOPE_EXEC; + + for (; ns; ns = ns->parent) + scope = max(scope, READ_ONCE(ns->memfd_noexec_scope)); + + return scope; +} +#else +static inline int pidns_memfd_noexec_scope(struct pid_namespace *ns) +{ + return 0; +} +#endif + extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct user_namespace *user_ns, struct pid_namespace *ns); extern void zap_pid_ns_processes(struct pid_namespace *pid_ns); @@ -70,6 +86,11 @@ static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns) return ns; } +static inline int pidns_memfd_noexec_scope(struct pid_namespace *ns) +{ + return 0; +} + static inline struct pid_namespace *copy_pid_ns(unsigned long flags, struct user_namespace *user_ns, struct pid_namespace *ns) { diff --git a/kernel/pid.c b/kernel/pid.c index 6a1d23a11026..fee14a4486a3 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -83,6 +83,9 @@ struct pid_namespace init_pid_ns = { #ifdef CONFIG_PID_NS .ns.ops = &pidns_operations, #endif +#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE) + .memfd_noexec_scope = MEMFD_NOEXEC_SCOPE_EXEC, +#endif }; EXPORT_SYMBOL_GPL(init_pid_ns); diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index 0bf44afe04dd..619972c78774 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -110,9 +110,9 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns ns->user_ns = get_user_ns(user_ns); ns->ucounts = ucounts; ns->pid_allocated = PIDNS_ADDING; - - initialize_memfd_noexec_scope(ns); - +#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE) + ns->memfd_noexec_scope = pidns_memfd_noexec_scope(parent_pid_ns); +#endif return ns; out_free_idr: diff --git a/kernel/pid_sysctl.h b/kernel/pid_sysctl.h index b26e027fc9cd..2ee41a3a1dfd 100644 --- a/kernel/pid_sysctl.h +++ b/kernel/pid_sysctl.h @@ -5,33 +5,30 @@ #include <linux/pid_namespace.h> #if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE) -static inline void initialize_memfd_noexec_scope(struct pid_namespace *ns) -{ - ns->memfd_noexec_scope = - task_active_pid_ns(current)->memfd_noexec_scope; -} - static int pid_mfd_noexec_dointvec_minmax(struct ctl_table *table, int write, void *buf, size_t *lenp, loff_t *ppos) { struct pid_namespace *ns = task_active_pid_ns(current); struct ctl_table table_copy; + int err, scope, parent_scope; if (write && !ns_capable(ns->user_ns, CAP_SYS_ADMIN)) return -EPERM; table_copy = *table; - if (ns != &init_pid_ns) - table_copy.data = &ns->memfd_noexec_scope; - /* - * set minimum to current value, the effect is only bigger - * value is accepted. - */ - if (*(int *)table_copy.data > *(int *)table_copy.extra1) - table_copy.extra1 = table_copy.data; + /* You cannot set a lower enforcement value than your parent. */ + parent_scope = pidns_memfd_noexec_scope(ns->parent); + /* Equivalent to pidns_memfd_noexec_scope(ns). */ + scope = max(READ_ONCE(ns->memfd_noexec_scope), parent_scope); + + table_copy.data = &scope; + table_copy.extra1 = &parent_scope; - return proc_dointvec_minmax(&table_copy, write, buf, lenp, ppos); + err = proc_dointvec_minmax(&table_copy, write, buf, lenp, ppos); + if (!err && write) + WRITE_ONCE(ns->memfd_noexec_scope, scope); + return err; } static struct ctl_table pid_ns_ctl_table_vm[] = { @@ -51,7 +48,6 @@ static inline void register_pid_ns_sysctl_table_vm(void) register_sysctl("vm", pid_ns_ctl_table_vm); } #else -static inline void initialize_memfd_noexec_scope(struct pid_namespace *ns) {} static inline void register_pid_ns_sysctl_table_vm(void) {} #endif diff --git a/mm/memfd.c b/mm/memfd.c index aa46521057ab..1cad1904fc26 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -271,7 +271,8 @@ long memfd_fcntl(struct file *file, unsigned int cmd, unsigned int arg) static int check_sysctl_memfd_noexec(unsigned int *flags) { #ifdef CONFIG_SYSCTL - int sysctl = task_active_pid_ns(current)->memfd_noexec_scope; + struct pid_namespace *ns = task_active_pid_ns(current); + int sysctl = pidns_memfd_noexec_scope(ns); if (!(*flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) { if (sysctl >= MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL) |