AOSP: android/perms.c: clean up error handling

There are a number of error conditions which, due to the way
ext2fs_dir_iterate2 operates, would not be propagated to the upper
layers of the call stack. As a result, certain error conditions,
such as not having enough room to allocate blocks for SELinux
labels, would fail silently, instead of causing a compile
failure.

As suggested in
https://android-review.googlesource.com/c/platform/external/e2fsprogs/+/324363
, add a error field to the caller's private data structure, and use the
bit in the field to indicate an error condition. Now, certain errors
which were silently ignored will cause a compile failure when compiling
Android.

Test: Artifically modify selabel_lookup() to return a failure, and
      verify Android doesn't compile.
Test: Verify Android compiles under normal circumstances.
Test: Artifically modify ino_add_xattr() to return a failure, and
      verify Android doesn't compile.
Bug: 117502873
Bug: 117567573
Bug: 117473440

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Change-Id: Icdb0105a77e98c3428f20d3c59bf824dcad5db8d
From AOSP commit: 7ca13b8b2953f93536ea09eb2ff19bd7cc85b3c1

diff --git a/contrib/android/perms.c b/contrib/android/perms.c
index 746b94b..3c42e59 100644 (file)
--- a/contrib/android/perms.c
+++ b/contrib/android/perms.c
@@ -25,6 +25,7 @@ struct inode_params {
        time_t fixed_time;
        const struct ugid_map* uid_map;
        const struct ugid_map* gid_map;
+       errcode_t error;
 };
 
 static errcode_t ino_add_xattr(ext2_filsys fs, ext2_ino_t ino, const char *name,
@@ -82,7 +83,7 @@ static errcode_t set_selinux_xattr(ext2_filsys fs, ext2_ino_t ino,
        if (retval < 0) {
                com_err(__func__, retval,
                        _("searching for label \"%s\""), params->filename);
-               exit(1);
+               return retval;
        }
 
        retval = ino_add_xattr(fs, ino,  "security." XATTR_SELINUX_SUFFIX,
@@ -249,8 +250,10 @@ static int walk_dir(ext2_ino_t dir EXT2FS_ATTR((unused)),
                return 0;
 
        if (asprintf(&params->filename, "%s/%.*s", params->path, name_len,
-                    de->name) < 0)
+                    de->name) < 0) {
+               params->error = ENOMEM;
                return -ENOMEM;
+        }
 
        if (!strncmp(de->name, "lost+found", 10)) {
                retval = set_selinux_xattr(params->fs, de->inode, params);
@@ -264,8 +267,10 @@ static int walk_dir(ext2_ino_t dir EXT2FS_ATTR((unused)),
                        char *cur_path = params->path;
                        char *cur_filename = params->filename;
                        params->path = params->filename;
-                       ext2fs_dir_iterate2(params->fs, de->inode, 0, NULL,
-                                           walk_dir, params);
+                       retval = ext2fs_dir_iterate2(params->fs, de->inode, 0, NULL,
+                                                    walk_dir, params);
+                       if (retval)
+                               goto end;
                        params->path = cur_path;
                        params->filename = cur_filename;
                }
@@ -273,6 +278,7 @@ static int walk_dir(ext2_ino_t dir EXT2FS_ATTR((unused)),
 
 end:
        free(params->filename);
+       params->error |= retval;
        return retval;
 }
 
@@ -298,6 +304,7 @@ errcode_t __android_configure_fs(ext2_filsys fs, char *src_dir,
                .mountpoint = mountpoint,
                .uid_map = uid_map,
                .gid_map = gid_map,
+               .error = 0
        };
 
        /* walk_dir will add the "/". Don't add it twice. */
@@ -308,8 +315,11 @@ errcode_t __android_configure_fs(ext2_filsys fs, char *src_dir,
        if (retval)
                return retval;
 
-       return ext2fs_dir_iterate2(fs, EXT2_ROOT_INO, 0, NULL, walk_dir,
-                                  &params);
+       retval = ext2fs_dir_iterate2(fs, EXT2_ROOT_INO, 0, NULL, walk_dir,
+                                    &params);
+       if (retval)
+               return retval;
+       return params.error;
 }
 
 errcode_t android_configure_fs(ext2_filsys fs, char *src_dir, char *target_out,