X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=libbb%2Fcopy_file.c;h=d804eccfaee8009cf55f6957233f6685b9f1e1f9;hb=defc1ea34074e7882724c460260d307cdf981a70;hp=a6cfe122da0ca1000dceb050ee02234f5f6ac14b;hpb=51742f4bb0c57a4d5063ece9437a2f34a42e52c8;p=oweals%2Fbusybox.git

diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index a6cfe122d..d804eccfa 100644
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -19,35 +19,48 @@
 // (or fail, if it points to dir/nonexistent location/etc).
 // This is strange, but POSIX-correct.
 // coreutils cp has --remove-destination to override this...
+//
+// NB: we have special code which still allows for "cp file /dev/node"
+// to work POSIX-ly (the only realistic case where it makes sense)
 
 #define DO_POSIX_CP 0  /* 1 - POSIX behavior, 0 - safe behavior */
 
-
+// errno must be set to relevant value ("why we cannot create dest?")
+// for POSIX mode to give reasonable error message
 static int ask_and_unlink(const char *dest, int flags)
 {
-	// If !DO_POSIX_CP, act as if -f is always in effect - we don't want
-	// "'file' exists" msg, we want unlink to be done (silently unless -i
-	// is also in effect).
-	// This prevents safe way from asking more questions than POSIX does.
+	int e = errno;
 #if DO_POSIX_CP
 	if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
-		fprintf(stderr, "'%s' exists\n", dest);
+		// Either it exists, or the *path* doesnt exist
+		bb_perror_msg("cannot create '%s'", dest);
 		return -1;
 	}
 #endif
+	// If !DO_POSIX_CP, act as if -f is always in effect - we don't want
+	// "cannot create" msg, we want unlink to be done (silently unless -i).
 
 	// TODO: maybe we should do it only if ctty is present?
 	if (flags & FILEUTILS_INTERACTIVE) {
 		// We would not do POSIX insanity. -i asks,
 		// then _unlinks_ the offender. Presto.
-		// (No opening without O_EXCL, no unlinks only if -f)
+		// (No "opening without O_EXCL", no "unlink only if -f")
 		// Or else we will end up having 3 open()s!
 		fprintf(stderr, "%s: overwrite '%s'? ", applet_name, dest);
 		if (!bb_ask_confirmation())
 			return 0; // not allowed to overwrite
 	}
 	if (unlink(dest) < 0) {
-		bb_perror_msg("cannot remove '%s'", dest);
+#if ENABLE_FEATURE_VERBOSE_CP_MESSAGE
+		if (e == errno && e == ENOENT) {
+			/* e == ENOTDIR is similar: path has non-dir component,
+			 * but in this case we don't even reach copy_file() */
+			bb_error_msg("cannot create '%s': Path does not exist", dest);
+			return -1; // error
+		}
+#endif
+		errno = e;
+		bb_perror_msg("cannot create '%s'", dest);
 		return -1; // error
 	}
 	return 1; // ok (to try again)
@@ -58,14 +71,17 @@ static int ask_and_unlink(const char *dest, int flags)
  *  0 copy is made or user answered "no" in interactive mode
  *    (failures to preserve mode/owner/times are not reported in exit code)
  */
-int copy_file(const char *source, const char *dest, int flags)
+int FAST_FUNC copy_file(const char *source, const char *dest, int flags)
 {
+	/* This is a recursive function, try to minimize stack usage */
+	/* NB: each struct stat is ~100 bytes */
 	struct stat source_stat;
 	struct stat dest_stat;
-	int status = 0;
+	signed char retval = 0;
 	signed char dest_exists = 0;
 	signed char ovr;
 
+/* Inverse of cp -d ("cp without -d") */
 #define FLAGS_DEREF (flags & FILEUTILS_DEREFERENCE)
 
 	if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) {
@@ -112,6 +128,7 @@ int copy_file(const char *source, const char *dest, int flags)
 
 	if (S_ISDIR(source_stat.st_mode)) {
 		DIR *dp;
+		const char *tp;
 		struct dirent *d;
 		mode_t saved_umask = 0;
 
@@ -120,12 +137,23 @@ int copy_file(const char *source, const char *dest, int flags)
 			return -1;
 		}
 
-		/* Create DEST.  */
+		/* Did we ever create source ourself before? */
+		tp = is_in_ino_dev_hashtable(&source_stat);
+		if (tp) {
+			/* We did! it's a recursion! man the lifeboats... */
+			bb_error_msg("recursion detected, omitting directory '%s'",
+					source);
+			return -1;
+		}
+
+		/* Create DEST */
 		if (dest_exists) {
 			if (!S_ISDIR(dest_stat.st_mode)) {
 				bb_error_msg("target '%s' is not a directory", dest);
 				return -1;
 			}
+			/* race here: user can substitute a symlink between
+			 * this check and actual creation of files inside dest */
 		} else {
 			mode_t mode;
 			saved_umask = umask(0);
@@ -133,22 +161,29 @@ int copy_file(const char *source, const char *dest, int flags)
 			mode = source_stat.st_mode;
 			if (!(flags & FILEUTILS_PRESERVE_STATUS))
 				mode = source_stat.st_mode & ~saved_umask;
+			/* Allow owner to access new dir (at least for now) */
 			mode |= S_IRWXU;
-
 			if (mkdir(dest, mode) < 0) {
 				umask(saved_umask);
 				bb_perror_msg("cannot create directory '%s'", dest);
 				return -1;
 			}
-
 			umask(saved_umask);
+			/* need stat info for add_to_ino_dev_hashtable */
+			if (lstat(dest, &dest_stat) < 0) {
+				bb_perror_msg("cannot stat '%s'", dest);
+				return -1;
+			}
 		}
+		/* remember (dev,inode) of each created dir.
+		 * NULL: name is not remembered */
+		add_to_ino_dev_hashtable(&dest_stat, NULL);
 
-		/* Recursively copy files in SOURCE.  */
+		/* Recursively copy files in SOURCE */
 		dp = opendir(source);
 		if (dp == NULL) {
-			status = -1;
-			goto preserve_status;
+			retval = -1;
+			goto preserve_mode_ugid_time;
 		}
 
 		while ((d = readdir(dp)) != NULL) {
@@ -159,7 +194,7 @@ int copy_file(const char *source, const char *dest, int flags)
 				continue;
 			new_dest = concat_path_file(dest, d->d_name);
 			if (copy_file(new_source, new_dest, flags) < 0)
-				status = -1;
+				retval = -1;
 			free(new_source);
 			free(new_dest);
 		}
@@ -168,11 +203,13 @@ int copy_file(const char *source, const char *dest, int flags)
 		if (!dest_exists
 		 && chmod(dest, source_stat.st_mode & ~saved_umask) < 0
 		) {
-			bb_perror_msg("cannot change permissions of '%s'", dest);
-			status = -1;
+			bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
+			/* retval = -1; - WRONG! copy *WAS* made */
 		}
+		goto preserve_mode_ugid_time;
+	}
 
-	} else if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
+	if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
 		int (*lf)(const char *oldpath, const char *newpath);
  make_links:
 		// Hmm... maybe
@@ -188,47 +225,68 @@ int copy_file(const char *source, const char *dest, int flags)
 				return -1;
 			}
 		}
+		/* _Not_ jumping to preserve_mode_ugid_time:
+		 * hard/softlinks don't have those */
 		return 0;
+	}
 
-	} else if (S_ISREG(source_stat.st_mode)
-	 /* Huh? DEREF uses stat, which never returns links! */
+	if (/* "cp thing1 thing2" without -R: just open and read() from thing1 */
+	    !(flags & FILEUTILS_RECUR)
+	    /* "cp [-opts] regular_file thing2" */
+	 || S_ISREG(source_stat.st_mode)
+	 /* DEREF uses stat, which never returns S_ISLNK() == true.
+	  * So the below is never true: */
 	 /* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */
 	) {
 		int src_fd;
 		int dst_fd;
-		if (ENABLE_FEATURE_PRESERVE_HARDLINKS) {
-			char *link_name;
-
-			if (!FLAGS_DEREF) {
-				link_name = is_in_ino_dev_hashtable(&source_stat);
-				if (link_name) {
-					if (link(link_name, dest) < 0) {
-						ovr = ask_and_unlink(dest, flags);
-						if (ovr <= 0)
-							return ovr;
-						if (link(link_name, dest) < 0) {
-							bb_perror_msg("cannot create link '%s'", dest);
-							return -1;
-						}
+		mode_t new_mode;
+
+		if (!FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) {
+			/* "cp -d symlink dst": create a link */
+			goto dont_cat;
+		}
+
+		if (ENABLE_FEATURE_PRESERVE_HARDLINKS && !FLAGS_DEREF) {
+			const char *link_target;
+			link_target = is_in_ino_dev_hashtable(&source_stat);
+			if (link_target) {
+				if (link(link_target, dest) < 0) {
+					ovr = ask_and_unlink(dest, flags);
+					if (ovr <= 0)
+						return ovr;
+					if (link(link_target, dest) < 0) {
+						bb_perror_msg("cannot create link '%s'", dest);
+						return -1;
 					}
-					return 0;
 				}
+				return 0;
 			}
 			add_to_ino_dev_hashtable(&source_stat, dest);
 		}
 
 		src_fd = open_or_warn(source, O_RDONLY);
-		if (src_fd < 0) {
+		if (src_fd < 0)
 			return -1;
-		}
 
-#if DO_POSIX_CP  /* POSIX way (a security problem versus symlink attacks!): */
-		dst_fd = open(dest, (flags & FILEUTILS_INTERACTIVE)
-				? O_WRONLY|O_CREAT|O_EXCL
-				: O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
-#else  /* safe way: */
-		dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, source_stat.st_mode);
-#endif
+		/* Do not try to open with weird mode fields */
+		new_mode = source_stat.st_mode;
+		if (!S_ISREG(source_stat.st_mode))
+			new_mode = 0666;
+
+		/* POSIX way is a security problem versus symlink attacks,
+		 * we do it only for non-symlinks, and only for non-recursive,
+		 * non-interactive cp. NB: it is still racy
+		 * for "cp file /home/bad_user/file" case
+		 * (user can rm file and create a link to /etc/passwd) */
+		if (DO_POSIX_CP
+		 || (dest_exists
+		     && !(flags & (FILEUTILS_RECUR|FILEUTILS_INTERACTIVE))
+		     && !S_ISLNK(dest_stat.st_mode))
+		) {
+			dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, new_mode);
+		} else  /* safe way: */
+			dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
 		if (dst_fd == -1) {
 			ovr = ask_and_unlink(dest, flags);
 			if (ovr <= 0) {
@@ -236,7 +294,7 @@ int copy_file(const char *source, const char *dest, int flags)
 				return ovr;
 			}
 			/* It shouldn't exist. If it exists, do not open (symlink attack?) */
-			dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, source_stat.st_mode);
+			dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
 			if (dst_fd < 0) {
 				close(src_fd);
 				return -1;
@@ -244,8 +302,7 @@ int copy_file(const char *source, const char *dest, int flags)
 		}
 
 #if ENABLE_SELINUX
-		if (((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT)
-		    || (flags & FILEUTILS_SET_SECURITY_CONTEXT))
+		if ((flags & (FILEUTILS_PRESERVE_SECURITY_CONTEXT|FILEUTILS_SET_SECURITY_CONTEXT))
 		 && is_selinux_enabled() > 0
 		) {
 			security_context_t con;
@@ -264,60 +321,60 @@ int copy_file(const char *source, const char *dest, int flags)
 		}
 #endif
 		if (bb_copyfd_eof(src_fd, dst_fd) == -1)
-			status = -1;
+			retval = -1;
+		/* Ok, writing side I can understand... */
 		if (close(dst_fd) < 0) {
 			bb_perror_msg("cannot close '%s'", dest);
-			status = -1;
-		}
-		if (close(src_fd) < 0) {
-			bb_perror_msg("cannot close '%s'", source);
-			status = -1;
+			retval = -1;
 		}
-
-	} else if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode)
-	 || S_ISSOCK(source_stat.st_mode) || S_ISFIFO(source_stat.st_mode)
-	 || S_ISLNK(source_stat.st_mode)
-	) {
-		// We are lazy here, a bit lax with races...
-		if (dest_exists) {
-			ovr = ask_and_unlink(dest, flags);
-			if (ovr <= 0)
-				return ovr;
-		}
-		if (S_ISFIFO(source_stat.st_mode)) {
-			if (mkfifo(dest, source_stat.st_mode) < 0) {
-				bb_perror_msg("cannot create fifo '%s'", dest);
-				return -1;
-			}
-		} else if (S_ISLNK(source_stat.st_mode)) {
-			char *lpath;
-
-			lpath = xmalloc_readlink_or_warn(source);
-			if (lpath && symlink(lpath, dest) < 0) {
+		/* ...but read size is already checked by bb_copyfd_eof */
+		close(src_fd);
+		/* "cp /dev/something new_file" should not
+		 * copy mode of /dev/something */
+		if (!S_ISREG(source_stat.st_mode))
+			return retval;
+		goto preserve_mode_ugid_time;
+	}
+ dont_cat:
+
+	/* Source is a symlink or a special file */
+	/* We are lazy here, a bit lax with races... */
+	if (dest_exists) {
+		errno = EEXIST;
+		ovr = ask_and_unlink(dest, flags);
+		if (ovr <= 0)
+			return ovr;
+	}
+	if (S_ISLNK(source_stat.st_mode)) {
+		char *lpath = xmalloc_readlink_or_warn(source);
+		if (lpath) {
+			int r = symlink(lpath, dest);
+			free(lpath);
+			if (r < 0) {
 				bb_perror_msg("cannot create symlink '%s'", dest);
-				free(lpath);
 				return -1;
 			}
-			free(lpath);
-
 			if (flags & FILEUTILS_PRESERVE_STATUS)
 				if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0)
 					bb_perror_msg("cannot preserve %s of '%s'", "ownership", dest);
-
-			return 0;
-
-		} else {
-			if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
-				bb_perror_msg("cannot create '%s'", dest);
-				return -1;
-			}
+		}
+		/* _Not_ jumping to preserve_mode_ugid_time:
+		 * symlinks don't have those */
+		return 0;
+	}
+	if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode)
+	 || S_ISSOCK(source_stat.st_mode) || S_ISFIFO(source_stat.st_mode)
+	) {
+		if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
+			bb_perror_msg("cannot create '%s'", dest);
+			return -1;
 		}
 	} else {
-		bb_error_msg("internal error: unrecognized file type");
+		bb_error_msg("unrecognized file '%s' with mode %x", source, source_stat.st_mode);
 		return -1;
 	}
 
- preserve_status:
+ preserve_mode_ugid_time:
 
 	if (flags & FILEUTILS_PRESERVE_STATUS
 	/* Cannot happen: */
@@ -327,6 +384,7 @@ int copy_file(const char *source, const char *dest, int flags)
 
 		times.actime = source_stat.st_atime;
 		times.modtime = source_stat.st_mtime;
+		/* BTW, utimes sets usec-precision time - just FYI */
 		if (utime(dest, &times) < 0)
 			bb_perror_msg("cannot preserve %s of '%s'", "times", dest);
 		if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) {
@@ -337,5 +395,5 @@ int copy_file(const char *source, const char *dest, int flags)
 			bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
 	}
 
-	return status;
+	return retval;
 }