fix parent-memory-clobber in posix_spawn (environ)

[musl] / src / process / posix_spawn.c

diff --git a/src/process/posix_spawn.c b/src/process/posix_spawn.c
index 7018c37..c3e800b 100644 (file)
--- a/src/process/posix_spawn.c
+++ b/src/process/posix_spawn.c
@@ -2,14 +2,27 @@
 #include <unistd.h>
 #include <signal.h>
 #include <stdint.h>
+#include <fcntl.h>
 #include "syscall.h"
+#include "pthread_impl.h"
+#include "fdop.h"
+#include "libc.h"
 
 extern char **environ;
 
-int __posix_spawnx(pid_t *res, const char *path,
-       int (*exec)(const char *, char *const *),
+static void dummy_0()
+{
+}
+weak_alias(dummy_0, __acquire_ptc);
+weak_alias(dummy_0, __release_ptc);
+
+pid_t __vfork(void);
+
+int __posix_spawnx(pid_t *restrict res, const char *restrict path,
+       int (*exec)(const char *, char *const *, char *const *),
        const posix_spawn_file_actions_t *fa,
-       const posix_spawnattr_t *attr, char **argv, char **envp)
+       const posix_spawnattr_t *restrict attr,
+       char *const argv[restrict], char *const envp[restrict])
 {
        pid_t pid;
        sigset_t oldmask;
@@ -18,8 +31,11 @@ int __posix_spawnx(pid_t *res, const char *path,
 
        if (!attr) attr = &dummy_attr;
 
-       sigprocmask(SIG_BLOCK, (void *)(uint64_t []){-1}, &oldmask);
-       pid = __syscall(SYS_fork);
+       sigprocmask(SIG_BLOCK, SIGALL_SET, &oldmask);
+
+       __acquire_ptc();
+       pid = __vfork();
+       __release_ptc();
 
        if (pid) {
                sigprocmask(SIG_SETMASK, &oldmask, 0);
@@ -28,14 +44,14 @@ int __posix_spawnx(pid_t *res, const char *path,
                return 0;
        }
 
-       for (i=1; i<=64; i++) {
+       for (i=1; i<=8*__SYSCALL_SSLEN; i++) {
                struct sigaction sa;
-               sigaction(i, 0, &sa);
-               if (sa.sa_handler!=SIG_IGN ||
+               __libc_sigaction(i, 0, &sa);
+               if (sa.sa_handler!=SIG_DFL && (sa.sa_handler!=SIG_IGN ||
                    ((attr->__flags & POSIX_SPAWN_SETSIGDEF)
-                    && sigismember(&attr->__def, i) )) {
+                    && sigismember(&attr->__def, i) ))) {
                        sa.sa_handler = SIG_DFL;
-                       sigaction(i, &sa, 0);
+                       __libc_sigaction(i, &sa, 0);
                }
        }
 
@@ -49,19 +65,46 @@ int __posix_spawnx(pid_t *res, const char *path,
                __syscall(SYS_setuid, __syscall(SYS_getuid)) ))
                _exit(127);
 
+       if (fa && fa->__actions) {
+               struct fdop *op;
+               int ret, fd;
+               for (op = fa->__actions; op->next; op = op->next);
+               for (; op; op = op->prev) {
+                       switch(op->cmd) {
+                       case FDOP_CLOSE:
+                               ret = __syscall(SYS_close, op->fd);
+                               break;
+                       case FDOP_DUP2:
+                               ret = __syscall(SYS_dup2, op->fd, op->newfd)<0;
+                               break;
+                       case FDOP_OPEN:
+                               fd = __syscall(SYS_open, op->path,
+                                       op->oflag | O_LARGEFILE, op->mode);
+                               if (fd == op->fd) {
+                                       ret = 0;
+                               } else {
+                                       ret = __syscall(SYS_dup2, fd, op->fd)<0;
+                                       __syscall(SYS_close, fd);
+                               }
+                               break;
+                       }
+                       if (ret) _exit(127);
+               }
+       }
+
        sigprocmask(SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK)
                ? &attr->__mask : &oldmask, 0);
 
-       if (envp) environ = envp;
-       exec(path, argv);
+       exec(path, argv, envp ? envp : environ);
        _exit(127);
 
        return 0;
 }
 
-int posix_spawn(pid_t *res, const char *path,
+int posix_spawn(pid_t *restrict res, const char *restrict path,
        const posix_spawn_file_actions_t *fa,
-       const posix_spawnattr_t *attr, char **argv, char **envp)
+       const posix_spawnattr_t *restrict attr,
+       char *const argv[restrict], char *const envp[restrict])
 {
-       return __posix_spawnx(res, path, execv, fa, attr, argv, envp);
+       return __posix_spawnx(res, path, execve, fa, attr, argv, envp);
 }