qvm-copy: Allow non-canonical symbolic links

These are used in the wild.  For instance, Busybox includes symlinks to
'./busybox' instead of just 'busybox'.

Fixes QubesOS/qubes-issues#10308

Author: DemiMarie

qubes-rpc/qfile-unpacker.c

@@ -106,7 +106,7 @@ int main(int argc, char ** argv)
     char *procdir_path;
     int procfs_fd;
     int i, ret;
-    int flags = COPY_ALLOW_SYMLINKS | COPY_ALLOW_DIRECTORIES;
+    int flags = COPY_ALLOW_SYMLINKS | COPY_ALLOW_DIRECTORIES | COPY_ALLOW_NON_CANONICAL_SYMLINKS;
     if (argc < 1)
         errx(EXIT_FAILURE, "NULL argv[0] passed to execve()");
     if (argc >= 3 && argv[1][0] >= '0' && argv[1][0] <= '9') {

qubes-rpc/qubes-fs-tree-check.c

@@ -146,7 +146,8 @@ process_dirent(const char *d_name, int fd, int flags, const char *name,
     // charset checks done already, do not repeat them
     if (qubes_pure_validate_symbolic_link_v2((const uint8_t *)name,
                                              (const uint8_t *)buf,
-                                             QUBES_PURE_ALLOW_UNSAFE_CHARACTERS) < 0)
+                                             QUBES_PURE_ALLOW_UNSAFE_CHARACTERS |
+                                             QUBES_PURE_ALLOW_NON_CANONICAL_SYMLINKS) < 0)
         errx(1, "Refusing to copy unsafe symbolic link %s", escaped);
     free(buf);
     return bad;