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seccomp: Rename SECCOMP_RET_KILL to SECCOMP_RET_KILL_THREAD

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In preparation for adding SECCOMP_RET_KILL_PROCESS, rename SECCOMP_RET_KILL
to the more accurate SECCOMP_RET_KILL_THREAD.

The existing selftest values are intentionally left as SECCOMP_RET_KILL
just to be sure we're exercising the alias.

Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2017-08-11 12:53:18 -07:00
parent 59f5cf44a3
commit fd76875ca2
7 changed files with 39 additions and 32 deletions
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2
Documentation/networking/filter.txt
View File

@ -337,7 +337,7 @@ Examples for low-level BPF:
jeq #14, good /* __NR_rt_sigprocmask */
jeq #13, good /* __NR_rt_sigaction */
jeq #35, good /* __NR_nanosleep */
bad: ret #0 /* SECCOMP_RET_KILL */
bad: ret #0 /* SECCOMP_RET_KILL_THREAD */
good: ret #0x7fff0000 /* SECCOMP_RET_ALLOW */
The above example code can be placed into a file (here called "foo"), and

4
Documentation/userspace-api/seccomp_filter.rst
View File

@ -87,11 +87,11 @@ Return values
A seccomp filter may return any of the following values. If multiple
filters exist, the return value for the evaluation of a given system
call will always use the highest precedent value. (For example,
``SECCOMP_RET_KILL`` will always take precedence.)
``SECCOMP_RET_KILL_THREAD`` will always take precedence.)
In precedence order, they are:
``SECCOMP_RET_KILL``:
``SECCOMP_RET_KILL_THREAD``:
Results in the task exiting immediately without executing the
system call. The exit status of the task (``status & 0x7f``) will
be ``SIGSYS``, not ``SIGKILL``.

3
include/uapi/linux/seccomp.h
View File

@ -27,7 +27,8 @@
* The ordering ensures that a min_t() over composed return values always
* selects the least permissive choice.
*/
#define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */
#define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */
#define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD
#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */

39
kernel/seccomp.c
View File

@ -192,7 +192,7 @@ static u32 seccomp_run_filters(const struct seccomp_data *sd,
/* Ensure unexpected behavior doesn't result in failing open. */
if (unlikely(WARN_ON(f == NULL)))
return SECCOMP_RET_KILL;
return SECCOMP_RET_KILL_THREAD;
if (!sd) {
populate_seccomp_data(&sd_local);
@ -529,15 +529,17 @@ static void seccomp_send_sigsys(int syscall, int reason)
#endif /* CONFIG_SECCOMP_FILTER */
/* For use with seccomp_actions_logged */
#define SECCOMP_LOG_KILL (1 << 0)
#define SECCOMP_LOG_KILL_THREAD (1 << 0)
#define SECCOMP_LOG_TRAP (1 << 2)
#define SECCOMP_LOG_ERRNO (1 << 3)
#define SECCOMP_LOG_TRACE (1 << 4)
#define SECCOMP_LOG_LOG (1 << 5)
#define SECCOMP_LOG_ALLOW (1 << 6)
static u32 seccomp_actions_logged = SECCOMP_LOG_KILL | SECCOMP_LOG_TRAP |
SECCOMP_LOG_ERRNO | SECCOMP_LOG_TRACE |
static u32 seccomp_actions_logged = SECCOMP_LOG_KILL_THREAD |
SECCOMP_LOG_TRAP |
SECCOMP_LOG_ERRNO |
SECCOMP_LOG_TRACE |
SECCOMP_LOG_LOG;
static inline void seccomp_log(unsigned long syscall, long signr, u32 action,
@ -560,13 +562,13 @@ static inline void seccomp_log(unsigned long syscall, long signr, u32 action,
case SECCOMP_RET_LOG:
log = seccomp_actions_logged & SECCOMP_LOG_LOG;
break;
case SECCOMP_RET_KILL:
case SECCOMP_RET_KILL_THREAD:
default:
log = seccomp_actions_logged & SECCOMP_LOG_KILL;
log = seccomp_actions_logged & SECCOMP_LOG_KILL_THREAD;
}
/*
* Force an audit message to be emitted when the action is RET_KILL,
* Force an audit message to be emitted when the action is RET_KILL_*,
* RET_LOG, or the FILTER_FLAG_LOG bit was set and the action is
* allowed to be logged by the admin.
*/
@ -605,7 +607,7 @@ static void __secure_computing_strict(int this_syscall)
#ifdef SECCOMP_DEBUG
dump_stack();
#endif
seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL, true);
seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL_THREAD, true);
do_exit(SIGKILL);
}
@ -716,7 +718,7 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
*/
return 0;
case SECCOMP_RET_KILL:
case SECCOMP_RET_KILL_THREAD:
default:
seccomp_log(this_syscall, SIGSYS, action, true);
/* Dump core only if this is the last remaining thread. */
@ -878,7 +880,7 @@ static long seccomp_get_action_avail(const char __user *uaction)
return -EFAULT;
switch (action) {
case SECCOMP_RET_KILL:
case SECCOMP_RET_KILL_THREAD:
case SECCOMP_RET_TRAP:
case SECCOMP_RET_ERRNO:
case SECCOMP_RET_TRACE:
@ -1029,19 +1031,20 @@ out:
#ifdef CONFIG_SYSCTL
/* Human readable action names for friendly sysctl interaction */
#define SECCOMP_RET_KILL_NAME "kill"
#define SECCOMP_RET_KILL_THREAD_NAME "kill_thread"
#define SECCOMP_RET_TRAP_NAME "trap"
#define SECCOMP_RET_ERRNO_NAME "errno"
#define SECCOMP_RET_TRACE_NAME "trace"
#define SECCOMP_RET_LOG_NAME "log"
#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_LOG_NAME " "
SECCOMP_RET_ALLOW_NAME;
static const char seccomp_actions_avail[] =
SECCOMP_RET_KILL_THREAD_NAME " "
SECCOMP_RET_TRAP_NAME " "
SECCOMP_RET_ERRNO_NAME " "
SECCOMP_RET_TRACE_NAME " "
SECCOMP_RET_LOG_NAME " "
SECCOMP_RET_ALLOW_NAME;
struct seccomp_log_name {
u32 log;
@ -1049,7 +1052,7 @@ struct seccomp_log_name {
};
static const struct seccomp_log_name seccomp_log_names[] = {
{ SECCOMP_LOG_KILL, SECCOMP_RET_KILL_NAME },
{ SECCOMP_LOG_KILL_THREAD, SECCOMP_RET_KILL_THREAD_NAME },
{ SECCOMP_LOG_TRAP, SECCOMP_RET_TRAP_NAME },
{ SECCOMP_LOG_ERRNO, SECCOMP_RET_ERRNO_NAME },
{ SECCOMP_LOG_TRACE, SECCOMP_RET_TRACE_NAME },

4
samples/seccomp/bpf-direct.c
View File

@ -129,7 +129,7 @@ static int install_filter(void)
/* Check that read is only using stdin. */
BPF_STMT(BPF_LD+BPF_W+BPF_ABS, syscall_arg(0)),
BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, STDIN_FILENO, 4, 0),
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL),
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL_THREAD),
/* Check that write is only using stdout */
BPF_STMT(BPF_LD+BPF_W+BPF_ABS, syscall_arg(0)),
@ -139,7 +139,7 @@ static int install_filter(void)
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW),
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_TRAP),
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL),
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL_THREAD),
};
struct sock_fprog prog = {
.len = (unsigned short)(sizeof(filter)/sizeof(filter[0])),

2
samples/seccomp/bpf-helper.h
View File

@ -44,7 +44,7 @@ void seccomp_bpf_print(struct sock_filter *filter, size_t count);
#define ALLOW \
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
#define DENY \
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)
BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL_THREAD)
#define JUMP(labels, label) \
BPF_JUMP(BPF_JMP+BPF_JA, FIND_LABEL((labels), (label)), \
JUMP_JT, JUMP_JF)

17
tools/testing/selftests/seccomp/seccomp_bpf.c
View File

@ -68,15 +68,18 @@
#define SECCOMP_MODE_FILTER 2
#endif
#ifndef SECCOMP_RET_KILL_THREAD
#define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */
#endif
#ifndef SECCOMP_RET_KILL
#define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */
#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
#define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD
#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
#endif
#ifndef SECCOMP_RET_LOG
#define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */
#define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */
#endif
#ifndef SECCOMP_RET_ACTION
@ -2696,7 +2699,7 @@ TEST_SIGNAL(filter_flag_log, SIGSYS)
TEST(get_action_avail)
{
__u32 actions[] = { SECCOMP_RET_KILL, SECCOMP_RET_TRAP,
__u32 actions[] = { SECCOMP_RET_KILL_THREAD, SECCOMP_RET_TRAP,
SECCOMP_RET_ERRNO, SECCOMP_RET_TRACE,
SECCOMP_RET_LOG, SECCOMP_RET_ALLOW };
__u32 unknown_action = 0x10000000U;