8c5dbf2ae0
Unfortunately struct siginfo has holes both in the common part of the structure, in the union members, and in the lack of padding of the union members. The result of those wholes is that the C standard does not guarantee those bits will be initialized. As struct siginfo is for communication between the kernel and userspace that is a problem. Add the helper function clear_siginfo that is guaranteed to clear all of the bits in struct siginfo so when the structure is copied there is no danger of copying old kernel data and causing a leak of information from kernel space to userspace. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
437 lines
12 KiB
C
437 lines
12 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SIGNAL_H
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#define _LINUX_SIGNAL_H
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#include <linux/bug.h>
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#include <linux/signal_types.h>
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#include <linux/string.h>
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struct task_struct;
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/* for sysctl */
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extern int print_fatal_signals;
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static inline void copy_siginfo(struct siginfo *to, const struct siginfo *from)
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{
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memcpy(to, from, sizeof(*to));
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}
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static inline void clear_siginfo(struct siginfo *info)
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{
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memset(info, 0, sizeof(*info));
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}
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int copy_siginfo_to_user(struct siginfo __user *to, const struct siginfo *from);
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enum siginfo_layout {
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SIL_KILL,
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SIL_TIMER,
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SIL_POLL,
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SIL_FAULT,
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SIL_CHLD,
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SIL_RT,
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#ifdef __ARCH_SIGSYS
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SIL_SYS,
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#endif
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};
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enum siginfo_layout siginfo_layout(int sig, int si_code);
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/*
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* Define some primitives to manipulate sigset_t.
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*/
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#ifndef __HAVE_ARCH_SIG_BITOPS
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#include <linux/bitops.h>
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/* We don't use <linux/bitops.h> for these because there is no need to
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be atomic. */
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static inline void sigaddset(sigset_t *set, int _sig)
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{
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unsigned long sig = _sig - 1;
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if (_NSIG_WORDS == 1)
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set->sig[0] |= 1UL << sig;
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else
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set->sig[sig / _NSIG_BPW] |= 1UL << (sig % _NSIG_BPW);
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}
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static inline void sigdelset(sigset_t *set, int _sig)
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{
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unsigned long sig = _sig - 1;
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if (_NSIG_WORDS == 1)
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set->sig[0] &= ~(1UL << sig);
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else
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set->sig[sig / _NSIG_BPW] &= ~(1UL << (sig % _NSIG_BPW));
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}
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static inline int sigismember(sigset_t *set, int _sig)
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{
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unsigned long sig = _sig - 1;
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if (_NSIG_WORDS == 1)
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return 1 & (set->sig[0] >> sig);
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else
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return 1 & (set->sig[sig / _NSIG_BPW] >> (sig % _NSIG_BPW));
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}
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#endif /* __HAVE_ARCH_SIG_BITOPS */
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static inline int sigisemptyset(sigset_t *set)
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{
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switch (_NSIG_WORDS) {
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case 4:
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return (set->sig[3] | set->sig[2] |
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set->sig[1] | set->sig[0]) == 0;
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case 2:
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return (set->sig[1] | set->sig[0]) == 0;
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case 1:
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return set->sig[0] == 0;
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default:
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BUILD_BUG();
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return 0;
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}
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}
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static inline int sigequalsets(const sigset_t *set1, const sigset_t *set2)
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{
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switch (_NSIG_WORDS) {
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case 4:
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return (set1->sig[3] == set2->sig[3]) &&
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(set1->sig[2] == set2->sig[2]) &&
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(set1->sig[1] == set2->sig[1]) &&
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(set1->sig[0] == set2->sig[0]);
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case 2:
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return (set1->sig[1] == set2->sig[1]) &&
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(set1->sig[0] == set2->sig[0]);
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case 1:
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return set1->sig[0] == set2->sig[0];
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}
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return 0;
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}
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#define sigmask(sig) (1UL << ((sig) - 1))
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#ifndef __HAVE_ARCH_SIG_SETOPS
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#include <linux/string.h>
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#define _SIG_SET_BINOP(name, op) \
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static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
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{ \
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unsigned long a0, a1, a2, a3, b0, b1, b2, b3; \
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\
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switch (_NSIG_WORDS) { \
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case 4: \
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a3 = a->sig[3]; a2 = a->sig[2]; \
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b3 = b->sig[3]; b2 = b->sig[2]; \
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r->sig[3] = op(a3, b3); \
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r->sig[2] = op(a2, b2); \
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case 2: \
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a1 = a->sig[1]; b1 = b->sig[1]; \
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r->sig[1] = op(a1, b1); \
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case 1: \
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a0 = a->sig[0]; b0 = b->sig[0]; \
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r->sig[0] = op(a0, b0); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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}
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#define _sig_or(x,y) ((x) | (y))
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_SIG_SET_BINOP(sigorsets, _sig_or)
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#define _sig_and(x,y) ((x) & (y))
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_SIG_SET_BINOP(sigandsets, _sig_and)
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#define _sig_andn(x,y) ((x) & ~(y))
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_SIG_SET_BINOP(sigandnsets, _sig_andn)
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#undef _SIG_SET_BINOP
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#undef _sig_or
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#undef _sig_and
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#undef _sig_andn
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#define _SIG_SET_OP(name, op) \
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static inline void name(sigset_t *set) \
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{ \
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switch (_NSIG_WORDS) { \
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case 4: set->sig[3] = op(set->sig[3]); \
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set->sig[2] = op(set->sig[2]); \
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case 2: set->sig[1] = op(set->sig[1]); \
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case 1: set->sig[0] = op(set->sig[0]); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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}
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#define _sig_not(x) (~(x))
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_SIG_SET_OP(signotset, _sig_not)
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#undef _SIG_SET_OP
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#undef _sig_not
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static inline void sigemptyset(sigset_t *set)
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{
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switch (_NSIG_WORDS) {
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default:
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memset(set, 0, sizeof(sigset_t));
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break;
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case 2: set->sig[1] = 0;
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case 1: set->sig[0] = 0;
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break;
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}
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}
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static inline void sigfillset(sigset_t *set)
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{
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switch (_NSIG_WORDS) {
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default:
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memset(set, -1, sizeof(sigset_t));
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break;
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case 2: set->sig[1] = -1;
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case 1: set->sig[0] = -1;
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break;
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}
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}
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/* Some extensions for manipulating the low 32 signals in particular. */
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static inline void sigaddsetmask(sigset_t *set, unsigned long mask)
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{
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set->sig[0] |= mask;
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}
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static inline void sigdelsetmask(sigset_t *set, unsigned long mask)
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{
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set->sig[0] &= ~mask;
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}
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static inline int sigtestsetmask(sigset_t *set, unsigned long mask)
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{
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return (set->sig[0] & mask) != 0;
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}
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static inline void siginitset(sigset_t *set, unsigned long mask)
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{
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set->sig[0] = mask;
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switch (_NSIG_WORDS) {
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default:
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memset(&set->sig[1], 0, sizeof(long)*(_NSIG_WORDS-1));
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break;
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case 2: set->sig[1] = 0;
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case 1: ;
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}
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}
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static inline void siginitsetinv(sigset_t *set, unsigned long mask)
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{
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set->sig[0] = ~mask;
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switch (_NSIG_WORDS) {
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default:
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memset(&set->sig[1], -1, sizeof(long)*(_NSIG_WORDS-1));
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break;
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case 2: set->sig[1] = -1;
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case 1: ;
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}
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}
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#endif /* __HAVE_ARCH_SIG_SETOPS */
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static inline void init_sigpending(struct sigpending *sig)
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{
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sigemptyset(&sig->signal);
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INIT_LIST_HEAD(&sig->list);
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}
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extern void flush_sigqueue(struct sigpending *queue);
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/* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
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static inline int valid_signal(unsigned long sig)
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{
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return sig <= _NSIG ? 1 : 0;
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}
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struct timespec;
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struct pt_regs;
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extern int next_signal(struct sigpending *pending, sigset_t *mask);
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extern int do_send_sig_info(int sig, struct siginfo *info,
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struct task_struct *p, bool group);
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extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p);
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extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
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extern int sigprocmask(int, sigset_t *, sigset_t *);
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extern void set_current_blocked(sigset_t *);
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extern void __set_current_blocked(const sigset_t *);
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extern int show_unhandled_signals;
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extern int get_signal(struct ksignal *ksig);
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extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping);
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extern void exit_signals(struct task_struct *tsk);
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extern void kernel_sigaction(int, __sighandler_t);
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static inline void allow_signal(int sig)
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{
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/*
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* Kernel threads handle their own signals. Let the signal code
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* know it'll be handled, so that they don't get converted to
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* SIGKILL or just silently dropped.
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*/
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kernel_sigaction(sig, (__force __sighandler_t)2);
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}
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static inline void disallow_signal(int sig)
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{
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kernel_sigaction(sig, SIG_IGN);
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}
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extern struct kmem_cache *sighand_cachep;
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int unhandled_signal(struct task_struct *tsk, int sig);
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/*
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* In POSIX a signal is sent either to a specific thread (Linux task)
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* or to the process as a whole (Linux thread group). How the signal
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* is sent determines whether it's to one thread or the whole group,
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* which determines which signal mask(s) are involved in blocking it
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* from being delivered until later. When the signal is delivered,
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* either it's caught or ignored by a user handler or it has a default
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* effect that applies to the whole thread group (POSIX process).
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*
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* The possible effects an unblocked signal set to SIG_DFL can have are:
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* ignore - Nothing Happens
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* terminate - kill the process, i.e. all threads in the group,
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* similar to exit_group. The group leader (only) reports
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* WIFSIGNALED status to its parent.
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* coredump - write a core dump file describing all threads using
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* the same mm and then kill all those threads
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* stop - stop all the threads in the group, i.e. TASK_STOPPED state
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*
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* SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.
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* Other signals when not blocked and set to SIG_DFL behaves as follows.
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* The job control signals also have other special effects.
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*
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* +--------------------+------------------+
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* | POSIX signal | default action |
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* +--------------------+------------------+
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* | SIGHUP | terminate |
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* | SIGINT | terminate |
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* | SIGQUIT | coredump |
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* | SIGILL | coredump |
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* | SIGTRAP | coredump |
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* | SIGABRT/SIGIOT | coredump |
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* | SIGBUS | coredump |
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* | SIGFPE | coredump |
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* | SIGKILL | terminate(+) |
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* | SIGUSR1 | terminate |
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* | SIGSEGV | coredump |
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* | SIGUSR2 | terminate |
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* | SIGPIPE | terminate |
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* | SIGALRM | terminate |
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* | SIGTERM | terminate |
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* | SIGCHLD | ignore |
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* | SIGCONT | ignore(*) |
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* | SIGSTOP | stop(*)(+) |
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* | SIGTSTP | stop(*) |
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* | SIGTTIN | stop(*) |
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* | SIGTTOU | stop(*) |
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* | SIGURG | ignore |
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* | SIGXCPU | coredump |
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* | SIGXFSZ | coredump |
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* | SIGVTALRM | terminate |
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* | SIGPROF | terminate |
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* | SIGPOLL/SIGIO | terminate |
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* | SIGSYS/SIGUNUSED | coredump |
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* | SIGSTKFLT | terminate |
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* | SIGWINCH | ignore |
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* | SIGPWR | terminate |
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* | SIGRTMIN-SIGRTMAX | terminate |
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* +--------------------+------------------+
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* | non-POSIX signal | default action |
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* +--------------------+------------------+
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* | SIGEMT | coredump |
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* +--------------------+------------------+
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*
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* (+) For SIGKILL and SIGSTOP the action is "always", not just "default".
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* (*) Special job control effects:
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* When SIGCONT is sent, it resumes the process (all threads in the group)
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* from TASK_STOPPED state and also clears any pending/queued stop signals
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* (any of those marked with "stop(*)"). This happens regardless of blocking,
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* catching, or ignoring SIGCONT. When any stop signal is sent, it clears
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* any pending/queued SIGCONT signals; this happens regardless of blocking,
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* catching, or ignored the stop signal, though (except for SIGSTOP) the
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* default action of stopping the process may happen later or never.
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*/
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#ifdef SIGEMT
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#define SIGEMT_MASK rt_sigmask(SIGEMT)
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#else
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#define SIGEMT_MASK 0
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#endif
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#if SIGRTMIN > BITS_PER_LONG
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#define rt_sigmask(sig) (1ULL << ((sig)-1))
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#else
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#define rt_sigmask(sig) sigmask(sig)
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#endif
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#define siginmask(sig, mask) \
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((sig) < SIGRTMIN && (rt_sigmask(sig) & (mask)))
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#define SIG_KERNEL_ONLY_MASK (\
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rt_sigmask(SIGKILL) | rt_sigmask(SIGSTOP))
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#define SIG_KERNEL_STOP_MASK (\
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rt_sigmask(SIGSTOP) | rt_sigmask(SIGTSTP) | \
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rt_sigmask(SIGTTIN) | rt_sigmask(SIGTTOU) )
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#define SIG_KERNEL_COREDUMP_MASK (\
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rt_sigmask(SIGQUIT) | rt_sigmask(SIGILL) | \
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rt_sigmask(SIGTRAP) | rt_sigmask(SIGABRT) | \
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rt_sigmask(SIGFPE) | rt_sigmask(SIGSEGV) | \
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rt_sigmask(SIGBUS) | rt_sigmask(SIGSYS) | \
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rt_sigmask(SIGXCPU) | rt_sigmask(SIGXFSZ) | \
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SIGEMT_MASK )
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#define SIG_KERNEL_IGNORE_MASK (\
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rt_sigmask(SIGCONT) | rt_sigmask(SIGCHLD) | \
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rt_sigmask(SIGWINCH) | rt_sigmask(SIGURG) )
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#define SIG_SPECIFIC_SICODES_MASK (\
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rt_sigmask(SIGILL) | rt_sigmask(SIGFPE) | \
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rt_sigmask(SIGSEGV) | rt_sigmask(SIGBUS) | \
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rt_sigmask(SIGTRAP) | rt_sigmask(SIGCHLD) | \
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rt_sigmask(SIGPOLL) | rt_sigmask(SIGSYS) | \
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SIGEMT_MASK )
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#define sig_kernel_only(sig) siginmask(sig, SIG_KERNEL_ONLY_MASK)
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#define sig_kernel_coredump(sig) siginmask(sig, SIG_KERNEL_COREDUMP_MASK)
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#define sig_kernel_ignore(sig) siginmask(sig, SIG_KERNEL_IGNORE_MASK)
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#define sig_kernel_stop(sig) siginmask(sig, SIG_KERNEL_STOP_MASK)
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#define sig_specific_sicodes(sig) siginmask(sig, SIG_SPECIFIC_SICODES_MASK)
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#define sig_fatal(t, signr) \
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(!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \
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(t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL)
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void signals_init(void);
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int restore_altstack(const stack_t __user *);
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int __save_altstack(stack_t __user *, unsigned long);
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#define save_altstack_ex(uss, sp) do { \
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stack_t __user *__uss = uss; \
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struct task_struct *t = current; \
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put_user_ex((void __user *)t->sas_ss_sp, &__uss->ss_sp); \
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put_user_ex(t->sas_ss_flags, &__uss->ss_flags); \
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put_user_ex(t->sas_ss_size, &__uss->ss_size); \
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if (t->sas_ss_flags & SS_AUTODISARM) \
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sas_ss_reset(t); \
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} while (0);
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#ifdef CONFIG_PROC_FS
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struct seq_file;
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extern void render_sigset_t(struct seq_file *, const char *, sigset_t *);
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#endif
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#endif /* _LINUX_SIGNAL_H */
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