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-rw-r--r--kernel/signal.c82
1 files changed, 64 insertions, 18 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 161cad4e448c..1c2dd117fee0 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2844,27 +2844,48 @@ COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
}
#endif
+static const struct {
+ unsigned char limit, layout;
+} sig_sicodes[] = {
+ [SIGILL] = { NSIGILL, SIL_FAULT },
+ [SIGFPE] = { NSIGFPE, SIL_FAULT },
+ [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
+ [SIGBUS] = { NSIGBUS, SIL_FAULT },
+ [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
+#if defined(SIGEMT)
+ [SIGEMT] = { NSIGEMT, SIL_FAULT },
+#endif
+ [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
+ [SIGPOLL] = { NSIGPOLL, SIL_POLL },
+ [SIGSYS] = { NSIGSYS, SIL_SYS },
+};
+
+static bool known_siginfo_layout(int sig, int si_code)
+{
+ if (si_code == SI_KERNEL)
+ return true;
+ else if ((si_code > SI_USER)) {
+ if (sig_specific_sicodes(sig)) {
+ if (si_code <= sig_sicodes[sig].limit)
+ return true;
+ }
+ else if (si_code <= NSIGPOLL)
+ return true;
+ }
+ else if (si_code >= SI_DETHREAD)
+ return true;
+ else if (si_code == SI_ASYNCNL)
+ return true;
+ return false;
+}
+
enum siginfo_layout siginfo_layout(int sig, int si_code)
{
enum siginfo_layout layout = SIL_KILL;
if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
- static const struct {
- unsigned char limit, layout;
- } filter[] = {
- [SIGILL] = { NSIGILL, SIL_FAULT },
- [SIGFPE] = { NSIGFPE, SIL_FAULT },
- [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
- [SIGBUS] = { NSIGBUS, SIL_FAULT },
- [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
-#if defined(SIGEMT)
- [SIGEMT] = { NSIGEMT, SIL_FAULT },
-#endif
- [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
- [SIGPOLL] = { NSIGPOLL, SIL_POLL },
- [SIGSYS] = { NSIGSYS, SIL_SYS },
- };
- if ((sig < ARRAY_SIZE(filter)) && (si_code <= filter[sig].limit)) {
- layout = filter[sig].layout;
+ if ((sig < ARRAY_SIZE(sig_sicodes)) &&
+ (si_code <= sig_sicodes[sig].limit)) {
+ layout = sig_sicodes[sig].layout;
/* Handle the exceptions */
if ((sig == SIGBUS) &&
(si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
@@ -2889,17 +2910,42 @@ enum siginfo_layout siginfo_layout(int sig, int si_code)
return layout;
}
+static inline char __user *si_expansion(const siginfo_t __user *info)
+{
+ return ((char __user *)info) + sizeof(struct kernel_siginfo);
+}
+
int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
{
+ char __user *expansion = si_expansion(to);
if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
return -EFAULT;
+ if (clear_user(expansion, SI_EXPANSION_SIZE))
+ return -EFAULT;
return 0;
}
int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
{
- if (copy_from_user(to, from, sizeof(struct siginfo)))
+ if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
return -EFAULT;
+ if (unlikely(!known_siginfo_layout(to->si_signo, to->si_code))) {
+ char __user *expansion = si_expansion(from);
+ char buf[SI_EXPANSION_SIZE];
+ int i;
+ /*
+ * An unknown si_code might need more than
+ * sizeof(struct kernel_siginfo) bytes. Verify all of the
+ * extra bytes are 0. This guarantees copy_siginfo_to_user
+ * will return this data to userspace exactly.
+ */
+ if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
+ return -EFAULT;
+ for (i = 0; i < SI_EXPANSION_SIZE; i++) {
+ if (buf[i] != 0)
+ return -E2BIG;
+ }
+ }
return 0;
}