cp: detect and prevent infinite recursion

diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index a86e497..b70d7b5 100644 (file)
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -114,6 +114,7 @@ int copy_file(const char *source, const char *dest, int flags)
 
        if (S_ISDIR(source_stat.st_mode)) {
                DIR *dp;
+               const char *existing_name;
                struct dirent *d;
                mode_t saved_umask = 0;
 
@@ -122,6 +123,15 @@ int copy_file(const char *source, const char *dest, int flags)
                        return -1;
                }
 
+               /* Did we ever create source ourself before? */
+               existing_name = is_in_ino_dev_hashtable(&source_stat);
+               if (existing_name) {
+                       /* We did! it's a recursion! man the lifeboats... */
+                       bb_error_msg("recursion detected, omitting directory '%s'",
+                                       existing_name);
+                       return -1;
+               }
+
                /* Create DEST */
                if (dest_exists) {
                        if (!S_ISDIR(dest_stat.st_mode)) {
@@ -143,7 +153,15 @@ int copy_file(const char *source, const char *dest, int flags)
                                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 */
                dp = opendir(source);
@@ -169,8 +187,8 @@ 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);
-                       retval = -1;
+                       bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
+                       /* retval = -1; - WRONG! copy *WAS* made */
                }
                goto preserve_mode_ugid_time;
        }
@@ -197,7 +215,7 @@ int copy_file(const char *source, const char *dest, int flags)
        }
 
        if (S_ISREG(source_stat.st_mode)
-        /* Huh? DEREF uses stat, which never returns links! */
+        /* DEREF uses stat, which never returns S_ISLNK() == true. */
         /* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */
        ) {
                int src_fd;
@@ -269,14 +287,13 @@ int copy_file(const char *source, const char *dest, int flags)
 #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;
                }
-               if (close(src_fd) < 0) {
-                       bb_perror_msg("cannot close '%s'", source);
-                       retval = -1;
-               }
+               /* ...but read size is already checked by bb_copyfd_eof */
+               close(src_fd);
                goto preserve_mode_ugid_time;
        }
 
@@ -289,18 +306,18 @@ int copy_file(const char *source, const char *dest, int flags)
                        return ovr;
        }
        if (S_ISLNK(source_stat.st_mode)) {
-               char *lpath;
-
-               lpath = xmalloc_readlink_or_warn(source);
-               if (lpath && symlink(lpath, dest) < 0) {
-                       bb_perror_msg("cannot create symlink '%s'", dest);
+               char *lpath = xmalloc_readlink_or_warn(source);
+               if (lpath) {
+                       int r = symlink(lpath, dest);
                        free(lpath);
-                       return -1;
+                       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);
                }
-               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);
                /* _Not_ jumping to preserve_mode_ugid_time:
                 * symlinks don't have those */
                return 0;
@@ -327,6 +344,7 @@ 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) {