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Fix the --no-overwrite-dir option
Given this option, tar failed to preserve permissions of empty directories and to create files under directories owned by the current user that did not have the S_IWUSR bit set. * src/extract.c (fd_chmod): Rename to fd_i_chmod. (fd_chmod): New function. (safe_dir_mode): New function. (extract_dir): Special handling for existing directories in --no-overwrite-dir mode. * tests/extrac23.at: New file. * tests/Makefile.am: Add new test case. * tests/testsuite.at: Likewise.
This commit is contained in:
Sergey Poznyakoff
+86
-42
@@ -194,7 +194,7 @@ extr_init (void)
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/* Use fchmod if possible, fchmodat otherwise. */
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static int
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fd_chmod (int fd, char const *file, mode_t mode, int atflag)
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fd_i_chmod (int fd, char const *file, mode_t mode, int atflag)
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{
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if (0 <= fd)
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{
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@@ -205,6 +205,42 @@ fd_chmod (int fd, char const *file, mode_t mode, int atflag)
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return fchmodat (chdir_fd, file, mode, atflag);
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}
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/* A version of fd_i_chmod which gracefully handles several common error
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conditions. Additional argument TYPEFLAG is the type of file in tar
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notation.
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*/
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static int
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fd_chmod(int fd, char const *file_name, int mode, int atflag, int typeflag)
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{
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int chmod_errno = fd_i_chmod (fd, file_name, mode, atflag) == 0 ? 0 : errno;
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/* On Solaris, chmod may fail if we don't have PRIV_ALL, because
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setuid-root files would otherwise be a backdoor. See
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http://opensolaris.org/jive/thread.jspa?threadID=95826
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(2009-09-03). */
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if (chmod_errno == EPERM && (mode & S_ISUID)
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&& priv_set_restore_linkdir () == 0)
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{
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chmod_errno = fd_i_chmod (fd, file_name, mode, atflag) == 0 ? 0 : errno;
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priv_set_remove_linkdir ();
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}
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/* Linux fchmodat does not support AT_SYMLINK_NOFOLLOW, and
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returns ENOTSUP even when operating on non-symlinks, try
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again with the flag disabled if it does not appear to be
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supported and if the file is not a symlink. This
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introduces a race, alas. */
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if (atflag && typeflag != SYMTYPE && ! implemented (chmod_errno))
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chmod_errno = fd_i_chmod (fd, file_name, mode, 0) == 0 ? 0 : errno;
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if (chmod_errno && (typeflag != SYMTYPE || implemented (chmod_errno)))
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{
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errno = chmod_errno;
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return -1;
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}
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return 0;
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}
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/* Use fchown if possible, fchownat otherwise. */
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static int
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fd_chown (int fd, char const *file, uid_t uid, gid_t gid, int atflag)
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@@ -259,35 +295,8 @@ set_mode (char const *file_name,
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if (current_mode != mode)
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{
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int chmod_errno =
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fd_chmod (fd, file_name, mode, atflag) == 0 ? 0 : errno;
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/* On Solaris, chmod may fail if we don't have PRIV_ALL, because
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setuid-root files would otherwise be a backdoor. See
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http://opensolaris.org/jive/thread.jspa?threadID=95826
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(2009-09-03). */
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if (chmod_errno == EPERM && (mode & S_ISUID)
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&& priv_set_restore_linkdir () == 0)
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{
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chmod_errno =
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fd_chmod (fd, file_name, mode, atflag) == 0 ? 0 : errno;
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priv_set_remove_linkdir ();
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}
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/* Linux fchmodat does not support AT_SYMLINK_NOFOLLOW, and
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returns ENOTSUP even when operating on non-symlinks, try
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again with the flag disabled if it does not appear to be
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supported and if the file is not a symlink. This
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introduces a race, alas. */
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if (atflag && typeflag != SYMTYPE && ! implemented (chmod_errno))
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chmod_errno = fd_chmod (fd, file_name, mode, 0) == 0 ? 0 : errno;
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if (chmod_errno
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&& (typeflag != SYMTYPE || implemented (chmod_errno)))
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{
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errno = chmod_errno;
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chmod_error_details (file_name, mode);
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}
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if (fd_chmod (fd, file_name, mode, atflag, typeflag))
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chmod_error_details (file_name, mode);
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}
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}
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}
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@@ -975,6 +984,26 @@ is_directory_link (const char *file_name)
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return res;
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}
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/* Given struct stat of a directory (or directory member) whose ownership
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or permissions of will be restored later, return the temporary permissions
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for that directory, sufficiently restrictive so that in the meantime
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processes owned by other users do not inadvertently create files under this
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directory that inherit the wrong owner, group, or permissions from the
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directory.
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If not root, though, make the directory writeable and searchable at first,
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so that files can be created under it.
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*/
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static inline int
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safe_dir_mode (struct stat const *st)
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{
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return ((st->st_mode
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& (0 < same_owner_option || 0 < same_permissions_option
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? S_IRWXU
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: MODE_RWX))
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| (we_are_root ? 0 : MODE_WXUSR));
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}
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/* Extractor functions for various member types */
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static int
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@@ -1004,18 +1033,7 @@ extract_dir (char *file_name, int typeflag)
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else if (typeflag == GNUTYPE_DUMPDIR)
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skip_member ();
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/* If ownership or permissions will be restored later, create the
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directory with restrictive permissions at first, so that in the
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meantime processes owned by other users do not inadvertently
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create files under this directory that inherit the wrong owner,
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group, or permissions from the directory. If not root, though,
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make the directory writeable and searchable at first, so that
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files can be created under it. */
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mode = ((current_stat_info.stat.st_mode
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& (0 < same_owner_option || 0 < same_permissions_option
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? S_IRWXU
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: MODE_RWX))
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| (we_are_root ? 0 : MODE_WXUSR));
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mode = safe_dir_mode (¤t_stat_info.stat);
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for (;;)
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{
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@@ -1031,6 +1049,7 @@ extract_dir (char *file_name, int typeflag)
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if (errno == EEXIST
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&& (interdir_made
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|| keep_directory_symlink_option
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|| old_files_option == NO_OVERWRITE_DIR_OLD_FILES
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|| old_files_option == DEFAULT_OLD_FILES
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|| old_files_option == OVERWRITE_OLD_FILES))
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{
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@@ -1051,6 +1070,31 @@ extract_dir (char *file_name, int typeflag)
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repair_delayed_set_stat (file_name, &st);
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return 0;
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}
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else if (old_files_option == NO_OVERWRITE_DIR_OLD_FILES)
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{
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/* Temporarily change the directory mode to a safe
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value, to be able to create files in it, should
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the need be.
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*/
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mode = safe_dir_mode (&st);
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status = fd_chmod(-1, file_name, mode,
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AT_SYMLINK_NOFOLLOW, DIRTYPE);
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if (status == 0)
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{
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/* Store the actual directory mode, to be restored
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later.
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*/
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current_stat_info.stat = st;
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current_mode = mode & ~ current_umask;
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current_mode_mask = MODE_RWX;
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atflag = AT_SYMLINK_NOFOLLOW;
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break;
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}
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else
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{
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chmod_error_details (file_name, mode);
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}
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}
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break;
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}
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}
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