X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=libbb%2Fcopy_file.c;h=d37d515627ed541bc5205ba747eb8d0b2410ef56;hb=b02cea12129f1aa484701317f38466ec9e1c8462;hp=9c1bba68994e9a172f63ddb55b94cd78f0aa1889;hpb=75220b55ffabfc93512a380d3a90fe21333a6ff9;p=oweals%2Fbusybox.git

diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index 9c1bba689..d37d51562 100644
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -2,82 +2,157 @@
 /*
  * Mini copy_file implementation for busybox
  *
- *
  * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
+ * SELinux support by Yuichi Nakamura <ynakam@hitachisoft.jp>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  *
  */
 
-#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"
 
+// 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 softlink, we overwrite softlink's 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...
+//
+// 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)
+{
+	int e = errno;
+#if DO_POSIX_CP
+	if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
+		// 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 "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("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)
+}
+
+/* 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 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 = 1;
-	int status = 0;
-
-	if (((flags & FILEUTILS_PRESERVE_SYMLINKS) &&
-			lstat(source, &source_stat) < 0) ||
-			(!(flags & FILEUTILS_PRESERVE_SYMLINKS) &&
-			 stat(source, &source_stat) < 0)) {
-		perror_msg("%s", source);
+	signed char retval = 0;
+	signed char dest_exists = 0;
+	signed char ovr;
+
+#define FLAGS_DEREF (flags & FILEUTILS_DEREFERENCE)
+
+	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("cannot stat '%s'", source);
 		return -1;
 	}
 
-	if (stat(dest, &dest_stat) < 0) {
+	if (lstat(dest, &dest_stat) < 0) {
 		if (errno != ENOENT) {
-			perror_msg("unable to stat `%s'", dest);
+			bb_perror_msg("cannot 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);
 			return -1;
 		}
-		dest_exists = 0;
+		dest_exists = 1;
 	}
 
-	if (dest_exists && source_stat.st_rdev == dest_stat.st_rdev &&
-			source_stat.st_ino == dest_stat.st_ino) {
-		error_msg("`%s' and `%s' are the same file", source, dest);
-		return -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("cannot set setfscreatecon %s", con);
+				freecon(con);
+				return -1;
+			}
+		} else if (errno == ENOTSUP || errno == ENODATA) {
+			setfscreatecon_or_die(NULL);
+		} else {
+			bb_perror_msg("cannot 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)) {
-			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.  */
+		/* Create DEST */
 		if (dest_exists) {
 			if (!S_ISDIR(dest_stat.st_mode)) {
-				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 {
 			mode_t mode;
 			saved_umask = umask(0);
@@ -85,153 +160,219 @@ 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);
-				perror_msg("cannot create directory `%s'", dest);
+				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;
+			}
 		}
-
-		/* Recursively copy files in SOURCE.  */
-		if ((dp = opendir(source)) == NULL) {
-			perror_msg("unable to open directory `%s'", source);
-			status = -1;
-			goto end;
+		/* 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;
 
-			if (strcmp(d->d_name, ".") == 0 ||
-					strcmp(d->d_name, "..") == 0)
+			new_source = concat_subpath_file(source, d->d_name);
+			if (new_source == NULL)
 				continue;
-
-			new_source = concat_path_file(source, d->d_name);
 			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);
 		}
+		closedir(dp);
 
-		/* ??? What if an error occurs in readdir?  */
-
-		if (closedir(dp) < 0) {
-			perror_msg("unable to close directory `%s'", source);
-			status = -1;
+		if (!dest_exists
+		 && chmod(dest, source_stat.st_mode & ~saved_umask) < 0
+		) {
+			bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
+			/* retval = -1; - WRONG! copy *WAS* made */
 		}
+		goto preserve_mode_ugid_time;
+	}
 
-		if (!dest_exists &&
-				chmod(dest, source_stat.st_mode & ~saved_umask) < 0) {
-			perror_msg("unable to change permissions of `%s'", dest);
-			status = -1;
-		}
-	} else if (S_ISREG(source_stat.st_mode)) {
-		FILE *sfp, *dfp=NULL;
-
-		if (dest_exists) {
-			if (flags & FILEUTILS_INTERACTIVE) {
-				fprintf(stderr, "%s: overwrite `%s'? ", applet_name, dest);
-				if (!ask_confirmation())
-					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("cannot create link '%s'", dest);
+				return -1;
 			}
+		}
+		/* _Not_ jumping to preserve_mode_ugid_time:
+		 * hard/softlinks don't have those */
+		return 0;
+	}
 
-			if ((dfp = fopen(dest, "w")) == NULL) {
-				if (!(flags & FILEUTILS_FORCE)) {
-					perror_msg("unable to open `%s'", dest);
-					return -1;
-				}
-
-				if (unlink(dest) < 0) {
-					perror_msg("unable to remove `%s'", dest);
-					return -1;
+	if (S_ISREG(source_stat.st_mode)
+	 /* DEREF uses stat, which never returns S_ISLNK() == true. */
+	 /* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */
+	) {
+		int src_fd;
+		int dst_fd;
+
+		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;
+					}
 				}
-
-				dest_exists = 0;
+				return 0;
 			}
+			add_to_ino_dev_hashtable(&source_stat, dest);
 		}
 
-		if (!dest_exists) {
-			int fd;
+		src_fd = open_or_warn(source, O_RDONLY);
+		if (src_fd < 0)
+			return -1;
 
-			if ((fd = open(dest, O_WRONLY|O_CREAT, source_stat.st_mode)) < 0 ||
-					(dfp = fdopen(fd, "w")) == NULL) {
-				if (fd >= 0)
-					close(fd);
-				perror_msg("unable to open `%s'", dest);
+		/* 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, source_stat.st_mode);
+		} else  /* safe way: */
+			dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, source_stat.st_mode);
+		if (dst_fd == -1) {
+			ovr = ask_and_unlink(dest, flags);
+			if (ovr <= 0) {
+				close(src_fd);
+				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);
+			if (dst_fd < 0) {
+				close(src_fd);
 				return -1;
 			}
 		}
 
-		if ((sfp = fopen(source, "r")) == NULL) {
-			fclose(dfp);
-			perror_msg("unable to open `%s'", source);
-			status = -1;
-			goto end;
+#if ENABLE_SELINUX
+		if (((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT)
+		    || (flags & 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);
+			}
 		}
-
-		if (copy_file_chunk(sfp, dfp, -1) < 0)
-			status = -1;
-
-		if (fclose(dfp) < 0) {
-			perror_msg("unable to close `%s'", dest);
-			status = -1;
+#endif
+		if (bb_copyfd_eof(src_fd, dst_fd) == -1)
+			retval = -1;
+		/* Ok, writing side I can understand... */
+		if (close(dst_fd) < 0) {
+			bb_perror_msg("cannot close '%s'", dest);
+			retval = -1;
 		}
+		/* ...but read size is already checked by bb_copyfd_eof */
+		close(src_fd);
+		goto preserve_mode_ugid_time;
+	}
 
-		if (fclose(sfp) < 0) {
-			perror_msg("unable to close `%s'", source);
-			status = -1;
+	/* 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);
+				return -1;
+			}
+			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);
 		}
-	} else if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode) ||
-			S_ISSOCK(source_stat.st_mode)) {
+		/* _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) {
-			perror_msg("unable to create `%s'", dest);
-			return -1;
-		}
-	} else if (S_ISFIFO(source_stat.st_mode)) {
-		if (mkfifo(dest, source_stat.st_mode) < 0) {
-			perror_msg("cannot create fifo `%s'", dest);
-			return -1;
-		}
-	} else if (S_ISLNK(source_stat.st_mode)) {
-		char *lpath = xreadlink(source);
-		if (symlink(lpath, dest) < 0) {
-			perror_msg("cannot create symlink `%s'", dest);
+			bb_perror_msg("cannot create '%s'", dest);
 			return -1;
 		}
-		free(lpath);
-
-#if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
-		if (flags & FILEUTILS_PRESERVE_STATUS)
-			if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0)
-				perror_msg("unable to preserve ownership of `%s'", dest);
-#endif
-		return 0;
 	} else {
-		error_msg("internal error: unrecognized file type");
+		bb_error_msg("unrecognized file '%s' with mode %x", source, source_stat.st_mode);
 		return -1;
 	}
 
-end:
+ preserve_mode_ugid_time:
 
-	if (flags & FILEUTILS_PRESERVE_STATUS) {
+	if (flags & FILEUTILS_PRESERVE_STATUS
+	/* Cannot happen: */
+	/* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */
+	) {
 		struct utimbuf times;
 
 		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)
-			perror_msg("unable to preserve times of `%s'", dest);
+			bb_perror_msg("cannot 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);
-			perror_msg("unable to preserve ownership of `%s'", dest);
+			bb_perror_msg("cannot preserve %s of '%s'", "ownership", dest);
 		}
 		if (chmod(dest, source_stat.st_mode) < 0)
-			perror_msg("unable to preserve permissions of `%s'", dest);
+			bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
 	}
 
-	return status;
+	return retval;
 }