Merge tag 'iwlwifi-next-for-kalle-2014-12-30' of https://git.kernel.org/pub/scm/linux...

[cascardo/linux.git] / fs / exec.c

diff --git a/fs/exec.c b/fs/exec.c
index 01aebe3..ad8798e 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -748,18 +748,25 @@ EXPORT_SYMBOL(setup_arg_pages);
 
 #endif /* CONFIG_MMU */
 
-static struct file *do_open_exec(struct filename *name)
+static struct file *do_open_execat(int fd, struct filename *name, int flags)
 {
        struct file *file;
        int err;
-       static const struct open_flags open_exec_flags = {
+       struct open_flags open_exec_flags = {
                .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
                .acc_mode = MAY_EXEC | MAY_OPEN,
                .intent = LOOKUP_OPEN,
                .lookup_flags = LOOKUP_FOLLOW,
        };
 
-       file = do_filp_open(AT_FDCWD, name, &open_exec_flags);
+       if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
+               return ERR_PTR(-EINVAL);
+       if (flags & AT_SYMLINK_NOFOLLOW)
+               open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW;
+       if (flags & AT_EMPTY_PATH)
+               open_exec_flags.lookup_flags |= LOOKUP_EMPTY;
+
+       file = do_filp_open(fd, name, &open_exec_flags);
        if (IS_ERR(file))
                goto out;
 
@@ -770,12 +777,13 @@ static struct file *do_open_exec(struct filename *name)
        if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
                goto exit;
 
-       fsnotify_open(file);
-
        err = deny_write_access(file);
        if (err)
                goto exit;
 
+       if (name->name[0] != '\0')
+               fsnotify_open(file);
+
 out:
        return file;
 
@@ -787,7 +795,7 @@ exit:
 struct file *open_exec(const char *name)
 {
        struct filename tmp = { .name = name };
-       return do_open_exec(&tmp);
+       return do_open_execat(AT_FDCWD, &tmp, 0);
 }
 EXPORT_SYMBOL(open_exec);
 
@@ -1428,10 +1436,12 @@ static int exec_binprm(struct linux_binprm *bprm)
 /*
  * sys_execve() executes a new program.
  */
-static int do_execve_common(struct filename *filename,
-                               struct user_arg_ptr argv,
-                               struct user_arg_ptr envp)
+static int do_execveat_common(int fd, struct filename *filename,
+                             struct user_arg_ptr argv,
+                             struct user_arg_ptr envp,
+                             int flags)
 {
+       char *pathbuf = NULL;
        struct linux_binprm *bprm;
        struct file *file;
        struct files_struct *displaced;
@@ -1472,7 +1482,7 @@ static int do_execve_common(struct filename *filename,
        check_unsafe_exec(bprm);
        current->in_execve = 1;
 
-       file = do_open_exec(filename);
+       file = do_open_execat(fd, filename, flags);
        retval = PTR_ERR(file);
        if (IS_ERR(file))
                goto out_unmark;
@@ -1480,7 +1490,28 @@ static int do_execve_common(struct filename *filename,
        sched_exec();
 
        bprm->file = file;
-       bprm->filename = bprm->interp = filename->name;
+       if (fd == AT_FDCWD || filename->name[0] == '/') {
+               bprm->filename = filename->name;
+       } else {
+               if (filename->name[0] == '\0')
+                       pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd);
+               else
+                       pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s",
+                                           fd, filename->name);
+               if (!pathbuf) {
+                       retval = -ENOMEM;
+                       goto out_unmark;
+               }
+               /*
+                * Record that a name derived from an O_CLOEXEC fd will be
+                * inaccessible after exec. Relies on having exclusive access to
+                * current->files (due to unshare_files above).
+                */
+               if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt)))
+                       bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE;
+               bprm->filename = pathbuf;
+       }
+       bprm->interp = bprm->filename;
 
        retval = bprm_mm_init(bprm);
        if (retval)
@@ -1521,6 +1552,7 @@ static int do_execve_common(struct filename *filename,
        acct_update_integrals(current);
        task_numa_free(current);
        free_bprm(bprm);
+       kfree(pathbuf);
        putname(filename);
        if (displaced)
                put_files_struct(displaced);
@@ -1538,6 +1570,7 @@ out_unmark:
 
 out_free:
        free_bprm(bprm);
+       kfree(pathbuf);
 
 out_files:
        if (displaced)
@@ -1553,7 +1586,18 @@ int do_execve(struct filename *filename,
 {
        struct user_arg_ptr argv = { .ptr.native = __argv };
        struct user_arg_ptr envp = { .ptr.native = __envp };
-       return do_execve_common(filename, argv, envp);
+       return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
+}
+
+int do_execveat(int fd, struct filename *filename,
+               const char __user *const __user *__argv,
+               const char __user *const __user *__envp,
+               int flags)
+{
+       struct user_arg_ptr argv = { .ptr.native = __argv };
+       struct user_arg_ptr envp = { .ptr.native = __envp };
+
+       return do_execveat_common(fd, filename, argv, envp, flags);
 }
 
 #ifdef CONFIG_COMPAT
@@ -1569,7 +1613,23 @@ static int compat_do_execve(struct filename *filename,
                .is_compat = true,
                .ptr.compat = __envp,
        };
-       return do_execve_common(filename, argv, envp);
+       return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
+}
+
+static int compat_do_execveat(int fd, struct filename *filename,
+                             const compat_uptr_t __user *__argv,
+                             const compat_uptr_t __user *__envp,
+                             int flags)
+{
+       struct user_arg_ptr argv = {
+               .is_compat = true,
+               .ptr.compat = __argv,
+       };
+       struct user_arg_ptr envp = {
+               .is_compat = true,
+               .ptr.compat = __envp,
+       };
+       return do_execveat_common(fd, filename, argv, envp, flags);
 }
 #endif
 
@@ -1609,6 +1669,20 @@ SYSCALL_DEFINE3(execve,
 {
        return do_execve(getname(filename), argv, envp);
 }
+
+SYSCALL_DEFINE5(execveat,
+               int, fd, const char __user *, filename,
+               const char __user *const __user *, argv,
+               const char __user *const __user *, envp,
+               int, flags)
+{
+       int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;
+
+       return do_execveat(fd,
+                          getname_flags(filename, lookup_flags, NULL),
+                          argv, envp, flags);
+}
+
 #ifdef CONFIG_COMPAT
 COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename,
        const compat_uptr_t __user *, argv,
@@ -1616,4 +1690,17 @@ COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename,
 {
        return compat_do_execve(getname(filename), argv, envp);
 }
+
+COMPAT_SYSCALL_DEFINE5(execveat, int, fd,
+                      const char __user *, filename,
+                      const compat_uptr_t __user *, argv,
+                      const compat_uptr_t __user *, envp,
+                      int,  flags)
+{
+       int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;
+
+       return compat_do_execveat(fd,
+                                 getname_flags(filename, lookup_flags, NULL),
+                                 argv, envp, flags);
+}
 #endif