Merge pull request #441 from giuseppe/unescape-dirs

main: Allow escaped colons in directory paths

.github/workflows/test.yaml

@@ -19,8 +19,8 @@ jobs:
           - arch: ppc64le
             distro: ubuntu_latest
     steps:
-      - uses: actions/checkout@v2.1.0
-      - uses: uraimo/run-on-arch-action@v2.8.1
+      - uses: actions/checkout@v4
+      - uses: uraimo/run-on-arch-action@v3.0.1
         name: Build
         id: build
         with:
@@ -42,7 +42,7 @@ jobs:
             make -j $(nproc)
 
       - name: Archive build artifacts
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4.6.2
         with:
           name: fuse-overlayfs-${{ matrix.arch }}-${{ matrix.distro }}
           path: |
@@ -61,7 +61,7 @@ jobs:
       TAGS: exclude_graphdriver_devicemapper exclude_graphdriver_btrfs no_libsubid
     steps:
     - name: checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: install dependencies
       run: |
@@ -88,7 +88,7 @@ jobs:
         sudo cp fuse-overlayfs /sbin
 
     - name: Archive build artifacts
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4.6.2
       with:
         name: fuse-overlayfs-x86_64-ubuntu-latest
         path: |
@@ -97,6 +97,9 @@ jobs:
 
     - name: run test
       run: |
+        sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
+        sudo sysctl -w kernel.apparmor_restrict_unprivileged_unconfined=0
+
         case "${{ matrix.test }}" in
             ovl-whiteouts)
                 sudo sh -c "(cd /unionmount-testsuite; unshare -m ./run --ov --fuse=fuse-overlayfs --xdev)"

main.c

@@ -1924,6 +1924,58 @@ cleanup_layerp (struct ovl_layer **p)
 
 #define cleanup_layer __attribute__ ((cleanup (cleanup_layerp)))
 
+static void
+unescape (char *input)
+{
+  char *dest = input;
+
+  if (input == NULL)
+    return;
+
+  for (; *input; input++)
+    {
+      if (*input == '\\')
+        continue;
+
+      *dest++ = *input;
+    }
+  *dest = '\0';
+}
+
+static char *
+get_next_path (char *it, char **saveptr)
+{
+  char *ret;
+
+  if (*saveptr == NULL)
+    *saveptr = it;
+
+  ret = *saveptr;
+
+  if (*ret == '\0')
+    return NULL;
+
+  while (1)
+    {
+      if (**saveptr == '\0')
+        break;
+
+      if (**saveptr == ':')
+        {
+          **saveptr = '\0';
+          (*saveptr)++;
+          break;
+        }
+      else if (**saveptr == '\\')
+        {
+          memmove (*saveptr, *saveptr + 1, strlen (*saveptr) + 1);
+        }
+
+      (*saveptr)++;
+    }
+  return ret;
+}
+
 static struct ovl_layer *
 read_dirs (struct ovl_data *lo, char *path, bool low, struct ovl_layer *layers)
 {
@@ -1942,7 +1994,7 @@ read_dirs (struct ovl_data *lo, char *path, bool low, struct ovl_layer *layers)
   while (last && last->next)
     last = last->next;
 
-  for (it = strtok_r (buf, ":", &saveptr); it; it = strtok_r (NULL, ":", &saveptr))
+  for (it = get_next_path (buf, &saveptr); it; it = get_next_path (NULL, &saveptr))
     {
       char *name, *data;
       char *it_path = it;
@@ -5755,18 +5807,7 @@ main (int argc, char *argv[])
   if (lo.mountpoint == NULL)
     error (EXIT_FAILURE, 0, "no mountpoint specified");
 
-  if (lo.upperdir != NULL)
-    {
-      cleanup_free char *full_path = NULL;
-
-      full_path = realpath (lo.upperdir, NULL);
-      if (full_path == NULL)
-        error (EXIT_FAILURE, errno, "cannot retrieve path for %s", lo.upperdir);
-
-      lo.upperdir = strdup (full_path);
-      if (lo.upperdir == NULL)
-        error (EXIT_FAILURE, errno, "cannot allocate memory");
-    }
+  unescape (lo.workdir);
 
   set_limits ();
   check_can_mknod (&lo);
@@ -5890,7 +5931,7 @@ main (int argc, char *argv[])
               if (! found)
                 {
                   /* If the mode is missing, set a standard value.  */
-                  ret = write_permission_xattr (&lo, get_upper_layer (&lo)->fd, lo.upperdir, 0, 0, 0555);
+                  ret = write_permission_xattr (&lo, get_upper_layer (&lo)->fd, get_upper_layer (&lo)->path, 0, 0, 0555);
                   if (ret < 0)
                     error (EXIT_FAILURE, errno, "write xattr `%s` to upperdir", name);
                 }

tests/fedora-installs.sh

@@ -2,17 +2,17 @@
 
 set -xeuo pipefail
 
-mkdir lower upper workdir merged
+mkdir lower:1 upper:2 workdir:3 merged
 
-fuse-overlayfs -o sync=0,lowerdir=lower,upperdir=upper,workdir=workdir,suid,dev merged
+fuse-overlayfs -o 'sync=0,lowerdir=lower\\:1,upperdir=upper\\:2,workdir=workdir\\:3,suid,dev' merged
 
 docker run --rm -v $(pwd)/merged:/merged fedora dnf --use-host-config --installroot /merged --releasever 41 install -y glibc-common gedit
 
 umount merged
 
 # Make sure workdir is empty, and move the upper layer down
-rm -rf workdir lower
-mv upper lower
+rm -rf lower:1 workdir:3
+mv upper:2 lower
 mkdir upper workdir
 
 gcc -static -o suid-test $(dirname $0)/suid-test.c