diff options
Diffstat (limited to 'security/yama')
| -rw-r--r-- | security/yama/Kconfig | 8 | ||||
| -rw-r--r-- | security/yama/yama_lsm.c | 57 |
2 files changed, 57 insertions, 8 deletions
diff --git a/security/yama/Kconfig b/security/yama/Kconfig index 51d6709d8bbd..20ef5143c0c0 100644 --- a/security/yama/Kconfig +++ b/security/yama/Kconfig @@ -11,3 +11,11 @@ config SECURITY_YAMA Further information can be found in Documentation/security/Yama.txt. If you are unsure how to answer this question, answer N. + +config SECURITY_YAMA_STACKED + bool "Yama stacked with other LSMs" + depends on SECURITY_YAMA + default n + help + When Yama is built into the kernel, force it to stack with the + selected primary LSM. diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c index 83554ee8a587..b4c29848b49d 100644 --- a/security/yama/yama_lsm.c +++ b/security/yama/yama_lsm.c @@ -100,7 +100,7 @@ static void yama_ptracer_del(struct task_struct *tracer, * yama_task_free - check for task_pid to remove from exception list * @task: task being removed */ -static void yama_task_free(struct task_struct *task) +void yama_task_free(struct task_struct *task) { yama_ptracer_del(task, task); } @@ -116,7 +116,7 @@ static void yama_task_free(struct task_struct *task) * Return 0 on success, -ve on error. -ENOSYS is returned when Yama * does not handle the given option. */ -static int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3, +int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5) { int rc; @@ -143,7 +143,7 @@ static int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3, if (arg2 == 0) { yama_ptracer_del(NULL, myself); rc = 0; - } else if (arg2 == PR_SET_PTRACER_ANY) { + } else if (arg2 == PR_SET_PTRACER_ANY || (int)arg2 == -1) { rc = yama_ptracer_add(NULL, myself); } else { struct task_struct *tracer; @@ -243,7 +243,7 @@ static int ptracer_exception_found(struct task_struct *tracer, * * Returns 0 if following the ptrace is allowed, -ve on error. */ -static int yama_ptrace_access_check(struct task_struct *child, +int yama_ptrace_access_check(struct task_struct *child, unsigned int mode) { int rc; @@ -279,24 +279,61 @@ static int yama_ptrace_access_check(struct task_struct *child, } if (rc) { - char name[sizeof(current->comm)]; printk_ratelimited(KERN_NOTICE "ptrace of pid %d was attempted by: %s (pid %d)\n", - child->pid, - get_task_comm(name, current), - current->pid); + child->pid, current->comm, current->pid); } return rc; } +/** + * yama_ptrace_traceme - validate PTRACE_TRACEME calls + * @parent: task that will become the ptracer of the current task + * + * Returns 0 if following the ptrace is allowed, -ve on error. + */ +int yama_ptrace_traceme(struct task_struct *parent) +{ + int rc; + + /* If standard caps disallows it, so does Yama. We should + * only tighten restrictions further. + */ + rc = cap_ptrace_traceme(parent); + if (rc) + return rc; + + /* Only disallow PTRACE_TRACEME on more aggressive settings. */ + switch (ptrace_scope) { + case YAMA_SCOPE_CAPABILITY: + if (!ns_capable(task_user_ns(parent), CAP_SYS_PTRACE)) + rc = -EPERM; + break; + case YAMA_SCOPE_NO_ATTACH: + rc = -EPERM; + break; + } + + if (rc) { + printk_ratelimited(KERN_NOTICE + "ptraceme of pid %d was attempted by: %s (pid %d)\n", + current->pid, parent->comm, parent->pid); + } + + return rc; +} + +#ifndef CONFIG_SECURITY_YAMA_STACKED static struct security_operations yama_ops = { .name = "yama", .ptrace_access_check = yama_ptrace_access_check, + .ptrace_traceme = yama_ptrace_traceme, .task_prctl = yama_task_prctl, .task_free = yama_task_free, }; +#endif #ifdef CONFIG_SYSCTL static int yama_dointvec_minmax(struct ctl_table *table, int write, @@ -343,13 +380,17 @@ static struct ctl_table yama_sysctl_table[] = { static __init int yama_init(void) { +#ifndef CONFIG_SECURITY_YAMA_STACKED if (!security_module_enable(&yama_ops)) return 0; +#endif printk(KERN_INFO "Yama: becoming mindful.\n"); +#ifndef CONFIG_SECURITY_YAMA_STACKED if (register_security(&yama_ops)) panic("Yama: kernel registration failed.\n"); +#endif #ifdef CONFIG_SYSCTL if (!register_sysctl_paths(yama_sysctl_path, yama_sysctl_table)) |