*: introduce and use FAST_FUNC: regparm on i386, otherwise no-on

[oweals/busybox.git] / libbb / copy_file.c

diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index 86449f27c853b0b654939a07d0243479e4ce1db6..d804eccfaee8009cf55f6957233f6685b9f1e1f9 100644 (file)
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -29,6 +29,7 @@
 // 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
@@ -50,7 +51,16 @@ static int ask_and_unlink(const char *dest, int flags)
                        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)
@@ -61,7 +71,7 @@ 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 */
@@ -71,6 +81,7 @@ int copy_file(const char *source, const char *dest, int flags)
        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) {
@@ -141,6 +152,8 @@ int copy_file(const char *source, const char *dest, int flags)
                                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);
@@ -217,12 +230,22 @@ int copy_file(const char *source, const char *dest, int flags)
                return 0;
        }
 
-       if (S_ISREG(source_stat.st_mode)
-        /* DEREF uses stat, which never returns S_ISLNK() == true. */
+       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 (!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;
@@ -246,18 +269,24 @@ int copy_file(const char *source, const char *dest, int flags)
                if (src_fd < 0)
                        return -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;
+
                /* POSIX way is a security problem versus symlink attacks,
-                * we do it only for dest's which are device nodes,
-                * and only for non-recursive, non-interactive cp. NB: it is still racy
-                * for "cp file /home/bad_user/device_node" case
-                * (user can rm device_node and create link to /etc/passwd) */
+                * 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_ISBLK(dest_stat.st_mode) || S_ISCHR(dest_stat.st_mode)))
+                || (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);
+                       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, source_stat.st_mode);
+                       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) {
@@ -265,7 +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;
@@ -273,8 +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;
@@ -301,8 +329,13 @@ int copy_file(const char *source, const char *dest, int flags)
                }
                /* ...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... */