diff options
Diffstat (limited to 'linux-user/syscall.c')
| -rw-r--r-- | linux-user/syscall.c | 266 |
1 files changed, 197 insertions, 69 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 032d338869..df70255e5f 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -110,6 +110,10 @@ int __clone2(int (*fn)(void *), void *child_stack_base, CLONE_PARENT_SETTID | CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID) //#define DEBUG +/* Define DEBUG_ERESTARTSYS to force every syscall to be restarted + * once. This exercises the codepaths for restart. + */ +//#define DEBUG_ERESTARTSYS //#include <linux/msdos_fs.h> #define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct linux_dirent [2]) @@ -355,18 +359,6 @@ static int sys_getcwd1(char *buf, size_t size) return strlen(buf)+1; } -static int sys_openat(int dirfd, const char *pathname, int flags, mode_t mode) -{ - /* - * open(2) has extra parameter 'mode' when called with - * flag O_CREAT. - */ - if ((flags & O_CREAT) != 0) { - return (openat(dirfd, pathname, flags, mode)); - } - return (openat(dirfd, pathname, flags)); -} - #ifdef TARGET_NR_utimensat #ifdef CONFIG_UTIMENSAT static int sys_utimensat(int dirfd, const char *pathname, @@ -438,15 +430,6 @@ _syscall5(int, sys_ppoll, struct pollfd *, fds, nfds_t, nfds, size_t, sigsetsize) #endif -#if defined(TARGET_NR_pselect6) -#ifndef __NR_pselect6 -# define __NR_pselect6 -1 -#endif -#define __NR_sys_pselect6 __NR_pselect6 -_syscall6(int, sys_pselect6, int, nfds, fd_set *, readfds, fd_set *, writefds, - fd_set *, exceptfds, struct timespec *, timeout, void *, sig); -#endif - #if defined(TARGET_NR_prlimit64) #ifndef __NR_prlimit64 # define __NR_prlimit64 -1 @@ -619,15 +602,19 @@ static uint16_t host_to_target_errno_table[ERRNO_TABLE_SIZE] = { static inline int host_to_target_errno(int err) { - if(host_to_target_errno_table[err]) + if (err >= 0 && err < ERRNO_TABLE_SIZE && + host_to_target_errno_table[err]) { return host_to_target_errno_table[err]; + } return err; } static inline int target_to_host_errno(int err) { - if (target_to_host_errno_table[err]) + if (err >= 0 && err < ERRNO_TABLE_SIZE && + target_to_host_errno_table[err]) { return target_to_host_errno_table[err]; + } return err; } @@ -652,6 +639,67 @@ char *target_strerror(int err) return strerror(target_to_host_errno(err)); } +#define safe_syscall0(type, name) \ +static type safe_##name(void) \ +{ \ + return safe_syscall(__NR_##name); \ +} + +#define safe_syscall1(type, name, type1, arg1) \ +static type safe_##name(type1 arg1) \ +{ \ + return safe_syscall(__NR_##name, arg1); \ +} + +#define safe_syscall2(type, name, type1, arg1, type2, arg2) \ +static type safe_##name(type1 arg1, type2 arg2) \ +{ \ + return safe_syscall(__NR_##name, arg1, arg2); \ +} + +#define safe_syscall3(type, name, type1, arg1, type2, arg2, type3, arg3) \ +static type safe_##name(type1 arg1, type2 arg2, type3 arg3) \ +{ \ + return safe_syscall(__NR_##name, arg1, arg2, arg3); \ +} + +#define safe_syscall4(type, name, type1, arg1, type2, arg2, type3, arg3, \ + type4, arg4) \ +static type safe_##name(type1 arg1, type2 arg2, type3 arg3, type4 arg4) \ +{ \ + return safe_syscall(__NR_##name, arg1, arg2, arg3, arg4); \ +} + +#define safe_syscall5(type, name, type1, arg1, type2, arg2, type3, arg3, \ + type4, arg4, type5, arg5) \ +static type safe_##name(type1 arg1, type2 arg2, type3 arg3, type4 arg4, \ + type5 arg5) \ +{ \ + return safe_syscall(__NR_##name, arg1, arg2, arg3, arg4, arg5); \ +} + +#define safe_syscall6(type, name, type1, arg1, type2, arg2, type3, arg3, \ + type4, arg4, type5, arg5, type6, arg6) \ +static type safe_##name(type1 arg1, type2 arg2, type3 arg3, type4 arg4, \ + type5 arg5, type6 arg6) \ +{ \ + return safe_syscall(__NR_##name, arg1, arg2, arg3, arg4, arg5, arg6); \ +} + +safe_syscall3(ssize_t, read, int, fd, void *, buff, size_t, count) +safe_syscall3(ssize_t, write, int, fd, const void *, buff, size_t, count) +safe_syscall4(int, openat, int, dirfd, const char *, pathname, \ + int, flags, mode_t, mode) +safe_syscall4(pid_t, wait4, pid_t, pid, int *, status, int, options, \ + struct rusage *, rusage) +safe_syscall5(int, waitid, idtype_t, idtype, id_t, id, siginfo_t *, infop, \ + int, options, struct rusage *, rusage) +safe_syscall3(int, execve, const char *, filename, char **, argv, char **, envp) +safe_syscall6(int, pselect6, int, nfds, fd_set *, readfds, fd_set *, writefds, \ + fd_set *, exceptfds, struct timespec *, timeout, void *, sig) +safe_syscall6(int,futex,int *,uaddr,int,op,int,val, \ + const struct timespec *,timeout,int *,uaddr2,int,val3) + static inline int host_to_target_sock_type(int host_type) { int target_type; @@ -1062,7 +1110,8 @@ static abi_long do_select(int n, { fd_set rfds, wfds, efds; fd_set *rfds_ptr, *wfds_ptr, *efds_ptr; - struct timeval tv, *tv_ptr; + struct timeval tv; + struct timespec ts, *ts_ptr; abi_long ret; ret = copy_from_user_fdset_ptr(&rfds, &rfds_ptr, rfd_addr, n); @@ -1081,12 +1130,15 @@ static abi_long do_select(int n, if (target_tv_addr) { if (copy_from_user_timeval(&tv, target_tv_addr)) return -TARGET_EFAULT; - tv_ptr = &tv; + ts.tv_sec = tv.tv_sec; + ts.tv_nsec = tv.tv_usec * 1000; + ts_ptr = &ts; } else { - tv_ptr = NULL; + ts_ptr = NULL; } - ret = get_errno(select(n, rfds_ptr, wfds_ptr, efds_ptr, tv_ptr)); + ret = get_errno(safe_pselect6(n, rfds_ptr, wfds_ptr, efds_ptr, + ts_ptr, NULL)); if (!is_error(ret)) { if (rfd_addr && copy_to_user_fdset(rfd_addr, &rfds, n)) @@ -1096,8 +1148,13 @@ static abi_long do_select(int n, if (efd_addr && copy_to_user_fdset(efd_addr, &efds, n)) return -TARGET_EFAULT; - if (target_tv_addr && copy_to_user_timeval(target_tv_addr, &tv)) - return -TARGET_EFAULT; + if (target_tv_addr) { + tv.tv_sec = ts.tv_sec; + tv.tv_usec = ts.tv_nsec / 1000; + if (copy_to_user_timeval(target_tv_addr, &tv)) { + return -TARGET_EFAULT; + } + } } return ret; @@ -3095,7 +3152,7 @@ static inline abi_long do_msgsnd(int msqid, abi_long msgp, } static inline abi_long do_msgrcv(int msqid, abi_long msgp, - unsigned int msgsz, abi_long msgtyp, + ssize_t msgsz, abi_long msgtyp, int msgflg) { struct target_msgbuf *target_mb; @@ -3103,10 +3160,18 @@ static inline abi_long do_msgrcv(int msqid, abi_long msgp, struct msgbuf *host_mb; abi_long ret = 0; + if (msgsz < 0) { + return -TARGET_EINVAL; + } + if (!lock_user_struct(VERIFY_WRITE, target_mb, msgp, 0)) return -TARGET_EFAULT; - host_mb = g_malloc(msgsz+sizeof(long)); + host_mb = g_try_malloc(msgsz + sizeof(long)); + if (!host_mb) { + ret = -TARGET_ENOMEM; + goto end; + } ret = get_errno(msgrcv(msqid, host_mb, msgsz, msgtyp, msgflg)); if (ret > 0) { @@ -5034,6 +5099,40 @@ static inline int tswapid(int id) #endif /* USE_UID16 */ +/* We must do direct syscalls for setting UID/GID, because we want to + * implement the Linux system call semantics of "change only for this thread", + * not the libc/POSIX semantics of "change for all threads in process". + * (See http://ewontfix.com/17/ for more details.) + * We use the 32-bit version of the syscalls if present; if it is not + * then either the host architecture supports 32-bit UIDs natively with + * the standard syscall, or the 16-bit UID is the best we can do. + */ +#ifdef __NR_setuid32 +#define __NR_sys_setuid __NR_setuid32 +#else +#define __NR_sys_setuid __NR_setuid +#endif +#ifdef __NR_setgid32 +#define __NR_sys_setgid __NR_setgid32 +#else +#define __NR_sys_setgid __NR_setgid +#endif +#ifdef __NR_setresuid32 +#define __NR_sys_setresuid __NR_setresuid32 +#else +#define __NR_sys_setresuid __NR_setresuid +#endif +#ifdef __NR_setresgid32 +#define __NR_sys_setresgid __NR_setresgid32 +#else +#define __NR_sys_setresgid __NR_setresgid +#endif + +_syscall1(int, sys_setuid, uid_t, uid) +_syscall1(int, sys_setgid, gid_t, gid) +_syscall3(int, sys_setresuid, uid_t, ruid, uid_t, euid, uid_t, suid) +_syscall3(int, sys_setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid) + void syscall_init(void) { IOCTLEntry *ie; @@ -5137,8 +5236,8 @@ static inline abi_long target_to_host_timespec(struct timespec *host_ts, if (!lock_user_struct(VERIFY_READ, target_ts, target_addr, 1)) return -TARGET_EFAULT; - host_ts->tv_sec = tswapal(target_ts->tv_sec); - host_ts->tv_nsec = tswapal(target_ts->tv_nsec); + __get_user(host_ts->tv_sec, &target_ts->tv_sec); + __get_user(host_ts->tv_nsec, &target_ts->tv_nsec); unlock_user_struct(target_ts, target_addr, 0); return 0; } @@ -5150,8 +5249,8 @@ static inline abi_long host_to_target_timespec(abi_ulong target_addr, if (!lock_user_struct(VERIFY_WRITE, target_ts, target_addr, 0)) return -TARGET_EFAULT; - target_ts->tv_sec = tswapal(host_ts->tv_sec); - target_ts->tv_nsec = tswapal(host_ts->tv_nsec); + __put_user(host_ts->tv_sec, &target_ts->tv_sec); + __put_user(host_ts->tv_nsec, &target_ts->tv_nsec); unlock_user_struct(target_ts, target_addr, 1); return 0; } @@ -5326,12 +5425,12 @@ static int do_futex(target_ulong uaddr, int op, int val, target_ulong timeout, } else { pts = NULL; } - return get_errno(sys_futex(g2h(uaddr), op, tswap32(val), + return get_errno(safe_futex(g2h(uaddr), op, tswap32(val), pts, NULL, val3)); case FUTEX_WAKE: - return get_errno(sys_futex(g2h(uaddr), op, val, NULL, NULL, 0)); + return get_errno(safe_futex(g2h(uaddr), op, val, NULL, NULL, 0)); case FUTEX_FD: - return get_errno(sys_futex(g2h(uaddr), op, val, NULL, NULL, 0)); + return get_errno(safe_futex(g2h(uaddr), op, val, NULL, NULL, 0)); case FUTEX_REQUEUE: case FUTEX_CMP_REQUEUE: case FUTEX_WAKE_OP: @@ -5341,11 +5440,11 @@ static int do_futex(target_ulong uaddr, int op, int val, target_ulong timeout, to satisfy the compiler. We do not need to tswap TIMEOUT since it's not compared to guest memory. */ pts = (struct timespec *)(uintptr_t) timeout; - return get_errno(sys_futex(g2h(uaddr), op, val, pts, - g2h(uaddr2), - (base_op == FUTEX_CMP_REQUEUE - ? tswap32(val3) - : val3))); + return get_errno(safe_futex(g2h(uaddr), op, val, pts, + g2h(uaddr2), + (base_op == FUTEX_CMP_REQUEUE + ? tswap32(val3) + : val3))); default: return -TARGET_ENOSYS; } @@ -5555,7 +5654,9 @@ static int open_self_cmdline(void *cpu_env, int fd) nb_read = read(fd_orig, buf, sizeof(buf)); if (nb_read < 0) { + int e = errno; fd_orig = close(fd_orig); + errno = e; return -1; } else if (nb_read == 0) { break; @@ -5575,7 +5676,9 @@ static int open_self_cmdline(void *cpu_env, int fd) if (word_skipped) { if (write(fd, cp_buf, nb_read) != nb_read) { + int e = errno; close(fd_orig); + errno = e; return -1; } } @@ -5595,7 +5698,7 @@ static int open_self_maps(void *cpu_env, int fd) fp = fopen("/proc/self/maps", "r"); if (fp == NULL) { - return -EACCES; + return -1; } while ((read = getline(&line, &len, fp)) != -1) { @@ -5739,7 +5842,7 @@ static int open_net_route(void *cpu_env, int fd) fp = fopen("/proc/net/route", "r"); if (fp == NULL) { - return -EACCES; + return -1; } /* read header */ @@ -5789,7 +5892,7 @@ static int do_openat(void *cpu_env, int dirfd, const char *pathname, int flags, if (is_proc_myself(pathname, "exe")) { int execfd = qemu_getauxval(AT_EXECFD); - return execfd ? execfd : get_errno(sys_openat(dirfd, exec_path, flags, mode)); + return execfd ? execfd : safe_openat(dirfd, exec_path, flags, mode); } for (fake_open = fakes; fake_open->filename; fake_open++) { @@ -5815,7 +5918,9 @@ static int do_openat(void *cpu_env, int dirfd, const char *pathname, int flags, unlink(filename); if ((r = fake_open->fill(cpu_env, fd))) { + int e = errno; close(fd); + errno = e; return r; } lseek(fd, 0, SEEK_SET); @@ -5823,7 +5928,7 @@ static int do_openat(void *cpu_env, int dirfd, const char *pathname, int flags, return fd; } - return get_errno(sys_openat(dirfd, path(pathname), flags, mode)); + return safe_openat(dirfd, path(pathname), flags, mode); } #define TIMER_MAGIC 0x0caf0000 @@ -5861,6 +5966,21 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, struct statfs stfs; void *p; +#if defined(DEBUG_ERESTARTSYS) + /* Debug-only code for exercising the syscall-restart code paths + * in the per-architecture cpu main loops: restart every syscall + * the guest makes once before letting it through. + */ + { + static int flag; + + flag = !flag; + if (flag) { + return -TARGET_ERESTARTSYS; + } + } +#endif + #ifdef DEBUG gemu_log("syscall %d", num); #endif @@ -5907,7 +6027,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, else { if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0))) goto efault; - ret = get_errno(read(arg1, p, arg3)); + ret = get_errno(safe_read(arg1, p, arg3)); if (ret >= 0 && fd_trans_host_to_target_data(arg1)) { ret = fd_trans_host_to_target_data(arg1)(p, ret); @@ -5918,7 +6038,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, case TARGET_NR_write: if (!(p = lock_user(VERIFY_READ, arg2, arg3, 1))) goto efault; - ret = get_errno(write(arg1, p, arg3)); + ret = get_errno(safe_write(arg1, p, arg3)); unlock_user(p, arg2, 0); break; #ifdef TARGET_NR_open @@ -5968,7 +6088,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, case TARGET_NR_waitpid: { int status; - ret = get_errno(waitpid(arg1, &status, arg3)); + ret = get_errno(safe_wait4(arg1, &status, arg3, 0)); if (!is_error(ret) && arg2 && ret && put_user_s32(host_to_target_waitstatus(status), arg2)) goto efault; @@ -5980,7 +6100,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, { siginfo_t info; info.si_pid = 0; - ret = get_errno(waitid(arg1, arg2, &info, arg4)); + ret = get_errno(safe_waitid(arg1, arg2, &info, arg4, NULL)); if (!is_error(ret) && arg3 && info.si_pid != 0) { if (!(p = lock_user(VERIFY_WRITE, arg3, sizeof(target_siginfo_t), 0))) goto efault; @@ -6106,7 +6226,17 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, if (!(p = lock_user_string(arg1))) goto execve_efault; - ret = get_errno(execve(p, argp, envp)); + /* Although execve() is not an interruptible syscall it is + * a special case where we must use the safe_syscall wrapper: + * if we allow a signal to happen before we make the host + * syscall then we will 'lose' it, because at the point of + * execve the process leaves QEMU's control. So we use the + * safe syscall wrapper to ensure that we either take the + * signal as a guest signal, or else it does not happen + * before the execve completes and makes it the other + * program's problem. + */ + ret = get_errno(safe_execve(p, argp, envp)); unlock_user(p, arg1, 0); goto execve_end; @@ -6930,12 +7060,10 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, break; #ifdef TARGET_NR_sigreturn case TARGET_NR_sigreturn: - /* NOTE: ret is eax, so not transcoding must be done */ ret = do_sigreturn(cpu_env); break; #endif case TARGET_NR_rt_sigreturn: - /* NOTE: ret is eax, so not transcoding must be done */ ret = do_rt_sigreturn(cpu_env); break; case TARGET_NR_sethostname: @@ -7124,8 +7252,8 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, sig_ptr = NULL; } - ret = get_errno(sys_pselect6(n, rfds_ptr, wfds_ptr, efds_ptr, - ts_ptr, sig_ptr)); + ret = get_errno(safe_pselect6(n, rfds_ptr, wfds_ptr, efds_ptr, + ts_ptr, sig_ptr)); if (!is_error(ret)) { if (rfd_addr && copy_to_user_fdset(rfd_addr, &rfds, n)) @@ -7694,7 +7822,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, rusage_ptr = &rusage; else rusage_ptr = NULL; - ret = get_errno(wait4(arg1, &status, arg3, rusage_ptr)); + ret = get_errno(safe_wait4(arg1, &status, arg3, rusage_ptr)); if (!is_error(ret)) { if (status_ptr && ret) { status = host_to_target_waitstatus(status); @@ -8740,9 +8868,9 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #endif #ifdef TARGET_NR_setresuid case TARGET_NR_setresuid: - ret = get_errno(setresuid(low2highuid(arg1), - low2highuid(arg2), - low2highuid(arg3))); + ret = get_errno(sys_setresuid(low2highuid(arg1), + low2highuid(arg2), + low2highuid(arg3))); break; #endif #ifdef TARGET_NR_getresuid @@ -8761,9 +8889,9 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #endif #ifdef TARGET_NR_getresgid case TARGET_NR_setresgid: - ret = get_errno(setresgid(low2highgid(arg1), - low2highgid(arg2), - low2highgid(arg3))); + ret = get_errno(sys_setresgid(low2highgid(arg1), + low2highgid(arg2), + low2highgid(arg3))); break; #endif #ifdef TARGET_NR_getresgid @@ -8789,10 +8917,10 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, break; #endif case TARGET_NR_setuid: - ret = get_errno(setuid(low2highuid(arg1))); + ret = get_errno(sys_setuid(low2highuid(arg1))); break; case TARGET_NR_setgid: - ret = get_errno(setgid(low2highgid(arg1))); + ret = get_errno(sys_setgid(low2highgid(arg1))); break; case TARGET_NR_setfsuid: ret = get_errno(setfsuid(arg1)); @@ -9074,7 +9202,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #endif #ifdef TARGET_NR_setresuid32 case TARGET_NR_setresuid32: - ret = get_errno(setresuid(arg1, arg2, arg3)); + ret = get_errno(sys_setresuid(arg1, arg2, arg3)); break; #endif #ifdef TARGET_NR_getresuid32 @@ -9093,7 +9221,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #endif #ifdef TARGET_NR_setresgid32 case TARGET_NR_setresgid32: - ret = get_errno(setresgid(arg1, arg2, arg3)); + ret = get_errno(sys_setresgid(arg1, arg2, arg3)); break; #endif #ifdef TARGET_NR_getresgid32 @@ -9120,12 +9248,12 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #endif #ifdef TARGET_NR_setuid32 case TARGET_NR_setuid32: - ret = get_errno(setuid(arg1)); + ret = get_errno(sys_setuid(arg1)); break; #endif #ifdef TARGET_NR_setgid32 case TARGET_NR_setgid32: - ret = get_errno(setgid(arg1)); + ret = get_errno(sys_setgid(arg1)); break; #endif #ifdef TARGET_NR_setfsuid32 |