diff options
Diffstat (limited to 'linux-user/strace.c')
| -rw-r--r-- | linux-user/strace.c | 113 |
1 files changed, 111 insertions, 2 deletions
diff --git a/linux-user/strace.c b/linux-user/strace.c index 5fbe067fd5..d821d165ff 100644 --- a/linux-user/strace.c +++ b/linux-user/strace.c @@ -188,6 +188,93 @@ static void print_si_code(int arg) gemu_log("%s", codename); } +static void get_target_siginfo(target_siginfo_t *tinfo, + const target_siginfo_t *info) +{ + abi_ulong sival_ptr; + + int sig; + int si_errno; + int si_code; + int si_type; + + __get_user(sig, &info->si_signo); + __get_user(si_errno, &tinfo->si_errno); + __get_user(si_code, &info->si_code); + + tinfo->si_signo = sig; + tinfo->si_errno = si_errno; + tinfo->si_code = si_code; + + /* Ensure we don't leak random junk to the guest later */ + 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 + * to tell, but the kernel carefully avoids giving userspace the + * high 16 bits of si_code, so we don't have the information to + * do this the easy way...) We therefore make our best guess, + * bearing in mind that a guest can spoof most of the si_codes + * via rt_sigqueueinfo() if it likes. + * + * Once we have made our guess, we record it in the top 16 bits of + * the si_code, so that print_siginfo() later can use it. + * print_siginfo() will strip these top bits out before printing + * the si_code. + */ + + switch (si_code) { + case SI_USER: + case SI_TKILL: + case SI_KERNEL: + /* Sent via kill(), tkill() or tgkill(), or direct from the kernel. + * These are the only unspoofable si_code values. + */ + __get_user(tinfo->_sifields._kill._pid, &info->_sifields._kill._pid); + __get_user(tinfo->_sifields._kill._uid, &info->_sifields._kill._uid); + si_type = QEMU_SI_KILL; + break; + default: + /* Everything else is spoofable. Make best guess based on signal */ + switch (sig) { + case TARGET_SIGCHLD: + __get_user(tinfo->_sifields._sigchld._pid, + &info->_sifields._sigchld._pid); + __get_user(tinfo->_sifields._sigchld._uid, + &info->_sifields._sigchld._uid); + __get_user(tinfo->_sifields._sigchld._status, + &info->_sifields._sigchld._status); + __get_user(tinfo->_sifields._sigchld._utime, + &info->_sifields._sigchld._utime); + __get_user(tinfo->_sifields._sigchld._stime, + &info->_sifields._sigchld._stime); + si_type = QEMU_SI_CHLD; + break; + case TARGET_SIGIO: + __get_user(tinfo->_sifields._sigpoll._band, + &info->_sifields._sigpoll._band); + __get_user(tinfo->_sifields._sigpoll._fd, + &info->_sifields._sigpoll._fd); + si_type = QEMU_SI_POLL; + break; + default: + /* Assume a sigqueue()/mq_notify()/rt_sigqueueinfo() source. */ + __get_user(tinfo->_sifields._rt._pid, &info->_sifields._rt._pid); + __get_user(tinfo->_sifields._rt._uid, &info->_sifields._rt._uid); + /* XXX: potential problem if 64 bit */ + __get_user(sival_ptr, &info->_sifields._rt._sigval.sival_ptr); + tinfo->_sifields._rt._sigval.sival_ptr = sival_ptr; + + si_type = QEMU_SI_RT; + break; + } + break; + } + + tinfo->si_code = deposit32(si_code, 16, 16, si_type); +} + static void print_siginfo(const target_siginfo_t *tinfo) { /* Print a target_siginfo_t in the format desired for printing @@ -1907,10 +1994,21 @@ print_rt_sigqueueinfo(const struct syscallname *name, abi_long arg0, abi_long arg1, abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5) { + void *p; + target_siginfo_t uinfo; + print_syscall_prologue(name); print_raw_param("%d", arg0, 0); print_signal(arg1, 0); - print_pointer(arg2, 1); + p = lock_user(VERIFY_READ, arg2, sizeof(target_siginfo_t), 1); + if (p) { + get_target_siginfo(&uinfo, p); + print_siginfo(&uinfo); + + unlock_user(p, arg2, 0); + } else { + print_pointer(arg2, 1); + } print_syscall_epilogue(name); } #endif @@ -1921,11 +2019,22 @@ print_rt_tgsigqueueinfo(const struct syscallname *name, abi_long arg0, abi_long arg1, abi_long arg2, abi_long arg3, abi_long arg4, abi_long arg5) { + void *p; + target_siginfo_t uinfo; + print_syscall_prologue(name); print_raw_param("%d", arg0, 0); print_raw_param("%d", arg1, 0); print_signal(arg2, 0); - print_pointer(arg3, 1); + p = lock_user(VERIFY_READ, arg3, sizeof(target_siginfo_t), 1); + if (p) { + get_target_siginfo(&uinfo, p); + print_siginfo(&uinfo); + + unlock_user(p, arg3, 0); + } else { + print_pointer(arg3, 1); + } print_syscall_epilogue(name); } #endif |