X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=libbb%2Fcopy_file.c;h=23c0f8320b86f19f5d1a478368843340bd1bf51b;hb=b05bcaf29c9008799aedb535cb42d2e60cc4cbb9;hp=3b172ffe48290ec9a9126a49f0c234212eaee19e;hpb=421d9e59416850968707dfec7a665cb0211b8d1c;p=oweals%2Fbusybox.git

diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index 3b172ffe4..23c0f8320 100644
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -3,255 +3,422 @@
  * Mini copy_file implementation for busybox
  *
  * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
+ * SELinux support by Yuichi Nakamura <ynakam@hitachisoft.jp>
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
- *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <utime.h>
-#include <errno.h>
-#include <dirent.h>
-#include <stdlib.h>
-#include <string.h>
-
 #include "libbb.h"
 
-/* Compiler version-specific crap that should be in a header file somewhere. */
+// FEATURE_NON_POSIX_CP:
+//
+// POSIX: if exists and -i, ask (w/o -i assume yes).
+// Then open w/o EXCL (yes, not unlink!).
+// If open still fails and -f, try unlink, then try open again.
+// Result: a mess:
+// If dest is a (sym)link, we overwrite link destination!
+// (or fail, if it points to dir/nonexistent location/etc).
+// This is strange, but POSIX-correct.
+// coreutils cp has --remove-destination to override this...
+
+/* Called if open of destination, link creation etc fails.
+ * errno must be set to relevant value ("why we cannot create dest?")
+ * to give reasonable error message */
+static int ask_and_unlink(const char *dest, int flags)
+{
+	int e = errno;
 
-#if !((__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1))
-#define lchown chown
+#if !ENABLE_FEATURE_NON_POSIX_CP
+	if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
+		/* Either it exists, or the *path* doesnt exist */
+		bb_perror_msg("can't create '%s'", dest);
+		return -1;
+	}
 #endif
+	// else: act as if -f is always in effect.
+	// We don't want "can't create" msg, we want unlink to be done
+	// (silently unless -i). Why? POSIX cp usually succeeds with
+	// O_TRUNC open of existing file, and user is left ignorantly happy.
+	// With above block unconditionally enabled, non-POSIX cp
+	// will complain a lot more than POSIX one.
+
+	/* 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 "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) {
+#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("can't create '%s': Path does not exist", dest);
+			return -1; /* error */
+		}
+#endif
+		errno = e; /* do not use errno from unlink */
+		bb_perror_msg("can't create '%s'", dest);
+		return -1; /* error */
+	}
+#if ENABLE_FEATURE_CP_LONG_OPTIONS
+	if (flags & FILEUTILS_RMDEST)
+		if (flags & FILEUTILS_VERBOSE)
+			printf("removed '%s'\n", dest);
+#endif
+	return 1; /* ok (to try again) */
+}
 
-
-int copy_file(const char *source, const char *dest, int flags)
+/* Return:
+ * -1 error, copy not made
+ *  0 copy is made or user answered "no" in interactive mode
+ *    (failures to preserve mode/owner/times are not reported in exit code)
+ */
+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 dest_exists = 0;
-	int status = 0;
-
-	if ((!(flags & FILEUTILS_DEREFERENCE) &&
-			lstat(source, &source_stat) < 0) ||
-			((flags & FILEUTILS_DEREFERENCE) &&
-			 stat(source, &source_stat) < 0)) {
-		bb_perror_msg("%s", source);
+	smallint retval = 0;
+	smallint dest_exists = 0;
+	smallint ovr;
+
+/* Inverse of cp -d ("cp without -d") */
+#define FLAGS_DEREF (flags & (FILEUTILS_DEREFERENCE + FILEUTILS_DEREFERENCE_L0))
+
+	if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) {
+		/* This may be a dangling symlink.
+		 * Making [sym]links to dangling symlinks works, so... */
+		if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK))
+			goto make_links;
+		bb_perror_msg("can't stat '%s'", source);
 		return -1;
 	}
 
 	if (lstat(dest, &dest_stat) < 0) {
 		if (errno != ENOENT) {
-			bb_perror_msg("unable to stat `%s'", dest);
+			bb_perror_msg("can't stat '%s'", dest);
 			return -1;
 		}
 	} else {
-		if (source_stat.st_dev == dest_stat.st_dev &&
-			source_stat.st_ino == dest_stat.st_ino)
-		{
-			bb_error_msg("`%s' and `%s' are the same file", source, dest);
+		if (source_stat.st_dev == dest_stat.st_dev
+		 && source_stat.st_ino == dest_stat.st_ino
+		) {
+			bb_error_msg("'%s' and '%s' are the same file", source, dest);
 			return -1;
 		}
 		dest_exists = 1;
 	}
 
+#if ENABLE_SELINUX
+	if ((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT) && is_selinux_enabled() > 0) {
+		security_context_t con;
+		if (lgetfilecon(source, &con) >= 0) {
+			if (setfscreatecon(con) < 0) {
+				bb_perror_msg("can't set setfscreatecon %s", con);
+				freecon(con);
+				return -1;
+			}
+		} else if (errno == ENOTSUP || errno == ENODATA) {
+			setfscreatecon_or_die(NULL);
+		} else {
+			bb_perror_msg("can't lgetfilecon %s", source);
+			return -1;
+		}
+	}
+#endif
+
 	if (S_ISDIR(source_stat.st_mode)) {
 		DIR *dp;
+		const char *tp;
 		struct dirent *d;
 		mode_t saved_umask = 0;
 
 		if (!(flags & FILEUTILS_RECUR)) {
-			bb_error_msg("%s: omitting directory", source);
+			bb_error_msg("omitting directory '%s'", source);
+			return -1;
+		}
+
+		/* 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("`%s' is not a directory", dest);
+				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 {
+			/* Create DEST */
 			mode_t mode;
 			saved_umask = umask(0);
 
 			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);
+				bb_perror_msg("can't 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("can't stat '%s'", dest);
+				return -1;
+			}
 		}
-
-		/* Recursively copy files in SOURCE.  */
-		if ((dp = opendir(source)) == NULL) {
-			bb_perror_msg("unable to open directory `%s'", source);
-			status = -1;
-			goto preserve_status;
+		/* 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 */
+		dp = opendir(source);
+		if (dp == NULL) {
+			retval = -1;
+			goto preserve_mode_ugid_time;
 		}
 
 		while ((d = readdir(dp)) != NULL) {
 			char *new_source, *new_dest;
 
 			new_source = concat_subpath_file(source, d->d_name);
-			if(new_source == NULL)
+			if (new_source == NULL)
 				continue;
 			new_dest = concat_path_file(dest, d->d_name);
-			if (copy_file(new_source, new_dest, flags) < 0)
-				status = -1;
+			if (copy_file(new_source, new_dest, flags & ~FILEUTILS_DEREFERENCE_L0) < 0)
+				retval = -1;
 			free(new_source);
 			free(new_dest);
 		}
-		/* closedir have only EBADF error, but "dp" not changes */
 		closedir(dp);
 
-		if (!dest_exists &&
-				chmod(dest, source_stat.st_mode & ~saved_umask) < 0) {
-			bb_perror_msg("unable to change permissions of `%s'", dest);
-			status = -1;
+		if (!dest_exists
+		 && chmod(dest, source_stat.st_mode & ~saved_umask) < 0
+		) {
+			bb_perror_msg("can't preserve %s of '%s'", "permissions", dest);
+			/* retval = -1; - WRONG! copy *WAS* made */
 		}
-	} else if (S_ISREG(source_stat.st_mode) || (flags & FILEUTILS_DEREFERENCE))
-	{
-		int src_fd;
-		int dst_fd;
-#ifdef CONFIG_FEATURE_PRESERVE_HARDLINKS
-		char *link_name;
+		goto preserve_mode_ugid_time;
+	}
 
-		if (!(flags & FILEUTILS_DEREFERENCE) &&
-				is_in_ino_dev_hashtable(&source_stat, &link_name)) {
-			if (link(link_name, dest) < 0) {
-				bb_perror_msg("unable to link `%s'", dest);
-				return -1;
+	if (dest_exists) {
+		if (flags & FILEUTILS_UPDATE) {
+			if (source_stat.st_mtime <= dest_stat.st_mtime) {
+				return 0; /* source file must be newer */
 			}
-
-			return 0;
 		}
-		add_to_ino_dev_hashtable(&source_stat, dest);
-#endif
-		src_fd = open(source, O_RDONLY);
-		if (src_fd == -1) {
-			bb_perror_msg("unable to open `%s'", source);
-			return(-1);
+#if ENABLE_FEATURE_CP_LONG_OPTIONS
+		if (flags & FILEUTILS_RMDEST) {
+			ovr = ask_and_unlink(dest, flags);
+			if (ovr <= 0)
+				return ovr;
+			dest_exists = 0;
 		}
+#endif
+	}
 
-		if (dest_exists) {
-			if (flags & FILEUTILS_INTERACTIVE) {
-				fprintf(stderr, "%s: overwrite `%s'? ", bb_applet_name, dest);
-				if (!bb_ask_confirmation()) {
-					close (src_fd);
-					return 0;
-				}
+	if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
+		int (*lf)(const char *oldpath, const char *newpath);
+ make_links:
+		/* Hmm... maybe
+		 * if (DEREF && MAKE_SOFTLINK) source = realpath(source) ?
+		 * (but realpath returns NULL on dangling symlinks...) */
+		lf = (flags & FILEUTILS_MAKE_SOFTLINK) ? symlink : link;
+		if (lf(source, dest) < 0) {
+			ovr = ask_and_unlink(dest, flags);
+			if (ovr <= 0)
+				return ovr;
+			if (lf(source, dest) < 0) {
+				bb_perror_msg("can't create link '%s'", dest);
+				return -1;
 			}
+		}
+		/* _Not_ jumping to preserve_mode_ugid_time:
+		 * (sym)links don't have those */
+		return 0;
+	}
 
-			dst_fd = open(dest, O_WRONLY|O_TRUNC);
-			if (dst_fd == -1) {
-				if (!(flags & FILEUTILS_FORCE)) {
-					bb_perror_msg("unable to open `%s'", dest);
-					close(src_fd);
-					return -1;
-				}
+	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;
+		mode_t new_mode;
 
-				if (unlink(dest) < 0) {
-					bb_perror_msg("unable to remove `%s'", dest);
-					close(src_fd);
-					return -1;
-				}
+		if (!FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) {
+			/* "cp -d symlink dst": create a link */
+			goto dont_cat;
+		}
 
-				goto dest_removed;
-			}
-		} else {
-dest_removed:
-			dst_fd = open(dest, O_WRONLY|O_CREAT, source_stat.st_mode);
-			if (dst_fd == -1) {
-				bb_perror_msg("unable to open `%s'", dest);
-				close(src_fd);
-				return(-1);
+		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("can't create link '%s'", dest);
+						return -1;
+					}
+				}
+				return 0;
 			}
+			add_to_ino_dev_hashtable(&source_stat, dest);
 		}
 
-		if (bb_copyfd_eof(src_fd, dst_fd) == -1)
-			status = -1;
-
-		if (close(dst_fd) < 0) {
-			bb_perror_msg("unable to close `%s'", dest);
-			status = -1;
-		}
+		src_fd = open_or_warn(source, O_RDONLY);
+		if (src_fd < 0)
+			return -1;
 
-		if (close(src_fd) < 0) {
-			bb_perror_msg("unable to close `%s'", source);
-			status = -1;
+		/* 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;
+
+		if (ENABLE_FEATURE_NON_POSIX_CP || (flags & FILEUTILS_INTERACTIVE)) {
+			/*
+			 * O_CREAT|O_EXCL: require that file did not exist before creation
+			 */
+			dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
+		} else { /* POSIX, and not "cp -i" */
+			/*
+			 * O_CREAT|O_TRUNC: create, or truncate (security problem versus (sym)link attacks)
+			 */
+			dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, new_mode);
 		}
-	} 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)) {
-
-		if (dest_exists) {
-			if((flags & FILEUTILS_FORCE) == 0) {
-				fprintf(stderr, "`%s' exists\n", dest);
-				return -1;
+		if (dst_fd == -1) {
+			ovr = ask_and_unlink(dest, flags);
+			if (ovr <= 0) {
+				close(src_fd);
+				return ovr;
 			}
-			if(unlink(dest) < 0) {
-				bb_perror_msg("unable to remove `%s'", dest);
+			/* It shouldn't exist. If it exists, do not open (symlink attack?) */
+			dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
+			if (dst_fd < 0) {
+				close(src_fd);
 				return -1;
 			}
 		}
-		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 = xreadlink(source);
-			if (symlink(lpath, dest) < 0) {
-				bb_perror_msg("cannot create symlink `%s'", dest);
+#if ENABLE_SELINUX
+		if ((flags & (FILEUTILS_PRESERVE_SECURITY_CONTEXT|FILEUTILS_SET_SECURITY_CONTEXT))
+		 && is_selinux_enabled() > 0
+		) {
+			security_context_t con;
+			if (getfscreatecon(&con) == -1) {
+				bb_perror_msg("getfscreatecon");
 				return -1;
 			}
+			if (con) {
+				if (setfilecon(dest, con) == -1) {
+					bb_perror_msg("setfilecon:%s,%s", dest, con);
+					freecon(con);
+					return -1;
+				}
+				freecon(con);
+			}
+		}
+#endif
+		if (bb_copyfd_eof(src_fd, dst_fd) == -1)
+			retval = -1;
+		/* Careful with writing... */
+		if (close(dst_fd) < 0) {
+			bb_perror_msg("error writing to '%s'", dest);
+			retval = -1;
+		}
+		/* ...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 (flags & FILEUTILS_PRESERVE_STATUS)
-				if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0)
-					bb_perror_msg("unable to preserve ownership of `%s'", dest);
-
-			return 0;
-
-		} else {
-			if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
-				bb_perror_msg("unable to create `%s'", dest);
+			if (r < 0) {
+				bb_perror_msg("can't create symlink '%s'", dest);
 				return -1;
 			}
+			if (flags & FILEUTILS_PRESERVE_STATUS)
+				if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0)
+					bb_perror_msg("can't preserve %s of '%s'", "ownership", dest);
+		}
+		/* _Not_ jumping to preserve_mode_ugid_time:
+		 * symlinks don't have those */
+		goto verb_and_exit;
+	}
+	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("can't 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) {
-		struct utimbuf times;
-		char *msg="unable to preserve %s of `%s'";
+	if (flags & FILEUTILS_PRESERVE_STATUS
+	/* Cannot happen: */
+	/* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */
+	) {
+		struct timeval times[2];
 
-		times.actime = source_stat.st_atime;
-		times.modtime = source_stat.st_mtime;
-		if (utime(dest, &times) < 0)
-			bb_perror_msg(msg, "times", dest);
+		times[1].tv_sec = times[0].tv_sec = source_stat.st_mtime;
+		times[1].tv_usec = times[0].tv_usec = 0;
+		/* BTW, utimes sets usec-precision time - just FYI */
+		if (utimes(dest, times) < 0)
+			bb_perror_msg("can't preserve %s of '%s'", "times", dest);
 		if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) {
 			source_stat.st_mode &= ~(S_ISUID | S_ISGID);
-			bb_perror_msg(msg, "ownership", dest);
+			bb_perror_msg("can't preserve %s of '%s'", "ownership", dest);
 		}
 		if (chmod(dest, source_stat.st_mode) < 0)
-			bb_perror_msg(msg, "permissions", dest);
+			bb_perror_msg("can't preserve %s of '%s'", "permissions", dest);
+	}
+
+ verb_and_exit:
+	if (flags & FILEUTILS_VERBOSE) {
+		printf("'%s' -> '%s'\n", source, dest);
 	}
 
-	return status;
+	return retval;
 }