diff options
| -rw-r--r-- | Documentation/sysctl/kernel.txt | 1 | ||||
| -rw-r--r-- | Documentation/userspace-api/seccomp_filter.rst | 16 | ||||
| -rw-r--r-- | kernel/seccomp.c | 51 |
3 files changed, 68 insertions, 0 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index bac23c198360..995c42cf86ba 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -74,6 +74,7 @@ show up in /proc/sys/kernel: - reboot-cmd [ SPARC only ] - rtsig-max - rtsig-nr +- seccomp/ ==> Documentation/userspace-api/seccomp_filter.rst - sem - sem_next_id [ sysv ipc ] - sg-big-buff [ generic SCSI device (sg) ] diff --git a/Documentation/userspace-api/seccomp_filter.rst b/Documentation/userspace-api/seccomp_filter.rst index f71eb5ef1f2d..35fc7cbf1d95 100644 --- a/Documentation/userspace-api/seccomp_filter.rst +++ b/Documentation/userspace-api/seccomp_filter.rst @@ -169,7 +169,23 @@ The ``samples/seccomp/`` directory contains both an x86-specific example and a more generic example of a higher level macro interface for BPF program generation. +Sysctls +======= + +Seccomp's sysctl files can be found in the ``/proc/sys/kernel/seccomp/`` +directory. Here's a description of each file in that directory: + +``actions_avail``: + A read-only ordered list of seccomp return values (refer to the + ``SECCOMP_RET_*`` macros above) in string form. The ordering, from + left-to-right, is the least permissive return value to the most + permissive return value. + The list represents the set of seccomp return values supported + by the kernel. A userspace program may use this list to + determine if the actions found in the ``seccomp.h``, when the + program was built, differs from the set of actions actually + supported in the current running kernel. Adding architecture support =========================== diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 1f3347fc2605..5f19f41e4e50 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -17,11 +17,13 @@ #include <linux/audit.h> #include <linux/compat.h> #include <linux/coredump.h> +#include <linux/kmemleak.h> #include <linux/sched.h> #include <linux/sched/task_stack.h> #include <linux/seccomp.h> #include <linux/slab.h> #include <linux/syscalls.h> +#include <linux/sysctl.h> #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER #include <asm/syscall.h> @@ -934,3 +936,52 @@ out: return ret; } #endif + +#ifdef CONFIG_SYSCTL + +/* Human readable action names for friendly sysctl interaction */ +#define SECCOMP_RET_KILL_NAME "kill" +#define SECCOMP_RET_TRAP_NAME "trap" +#define SECCOMP_RET_ERRNO_NAME "errno" +#define SECCOMP_RET_TRACE_NAME "trace" +#define SECCOMP_RET_ALLOW_NAME "allow" + +static const char seccomp_actions_avail[] = SECCOMP_RET_KILL_NAME " " + SECCOMP_RET_TRAP_NAME " " + SECCOMP_RET_ERRNO_NAME " " + SECCOMP_RET_TRACE_NAME " " + SECCOMP_RET_ALLOW_NAME; + +static struct ctl_path seccomp_sysctl_path[] = { + { .procname = "kernel", }, + { .procname = "seccomp", }, + { } +}; + +static struct ctl_table seccomp_sysctl_table[] = { + { + .procname = "actions_avail", + .data = (void *) &seccomp_actions_avail, + .maxlen = sizeof(seccomp_actions_avail), + .mode = 0444, + .proc_handler = proc_dostring, + }, + { } +}; + +static int __init seccomp_sysctl_init(void) +{ + struct ctl_table_header *hdr; + + hdr = register_sysctl_paths(seccomp_sysctl_path, seccomp_sysctl_table); + if (!hdr) + pr_warn("seccomp: sysctl registration failed\n"); + else + kmemleak_not_leak(hdr); + + return 0; +} + +device_initcall(seccomp_sysctl_init) + +#endif /* CONFIG_SYSCTL */ |