diff options
Diffstat (limited to 'linux-user/signal.c')
| -rw-r--r-- | linux-user/signal.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/linux-user/signal.c b/linux-user/signal.c index 1dadddf2dd..9d980456ec 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -278,6 +278,14 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo, tinfo->si_errno = 0; tinfo->si_code = info->si_code; + /* This memset serves two purposes: + * (1) ensure we don't leak random junk to the guest later + * (2) placate false positives from gcc about fields + * being used uninitialized if it chooses to inline both this + * function and tswap_siginfo() into host_to_target_siginfo(). + */ + memset(tinfo->_sifields._pad, 0, sizeof(tinfo->_sifields._pad)); + /* This is awkward, because we have to use a combination of * the si_code and si_signo to figure out which of the union's * members are valid. (Within the host kernel it is always possible @@ -397,8 +405,9 @@ static void tswap_siginfo(target_siginfo_t *tinfo, void host_to_target_siginfo(target_siginfo_t *tinfo, const siginfo_t *info) { - host_to_target_siginfo_noswap(tinfo, info); - tswap_siginfo(tinfo, tinfo); + target_siginfo_t tgt_tmp; + host_to_target_siginfo_noswap(&tgt_tmp, info); + tswap_siginfo(tinfo, &tgt_tmp); } /* XXX: we support only POSIX RT signals are used. */ @@ -627,8 +636,16 @@ static void host_signal_handler(int host_signum, siginfo_t *info, * code in case the guest code provokes one in the window between * now and it getting out to the main loop. Signals will be * unblocked again in process_pending_signals(). + * + * WARNING: we cannot use sigfillset() here because the uc_sigmask + * field is a kernel sigset_t, which is much smaller than the + * libc sigset_t which sigfillset() operates on. Using sigfillset() + * would write 0xff bytes off the end of the structure and trash + * data on the struct. + * We can't use sizeof(uc->uc_sigmask) either, because the libc + * headers define the struct field with the wrong (too large) type. */ - sigfillset(&uc->uc_sigmask); + memset(&uc->uc_sigmask, 0xff, SIGSET_T_SIZE); sigdelset(&uc->uc_sigmask, SIGSEGV); sigdelset(&uc->uc_sigmask, SIGBUS); |