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ANDROID: Incremental fs: Don't allow renaming .index directory.

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Add additional check to verify dentry is hashed after vfs_mkdir()
is successful.

Bug: 148423333
Test: kernel seftest - incfs_test, manual test removing .index when
mounted

Signed-off-by: Akilesh Kailash <akailash@google.com>
Change-Id: I7d2d71d480db4f02b7f3a347b5734c6643843594
This commit is contained in:
Akilesh Kailash 2020-07-18 00:26:46 +00:00
parent 2e35e4f844
commit 22b27c439f
2 changed files with 24 additions and 2 deletions
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14
fs/incfs/vfs.c
View File

@ -781,7 +781,8 @@ static struct dentry *open_or_create_index_dir(struct dentry *backing_dir)
if (err)
return ERR_PTR(err);
if (!d_really_is_positive(index_dentry)) {
if (!d_really_is_positive(index_dentry) ||
unlikely(d_unhashed(index_dentry))) {
dput(index_dentry);
return ERR_PTR(-EINVAL);
}
@ -1647,7 +1648,8 @@ static int dir_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
if (!err) {
struct inode *inode = NULL;
if (d_really_is_negative(backing_dentry)) {
if (d_really_is_negative(backing_dentry) ||
unlikely(d_unhashed(backing_dentry))) {
err = -EINVAL;
goto out;
}
@ -1872,6 +1874,13 @@ static int dir_rename(struct inode *old_dir, struct dentry *old_dentry,
return error;
backing_old_dentry = get_incfs_dentry(old_dentry)->backing_path.dentry;
if (!backing_old_dentry || backing_old_dentry == mi->mi_index_dir) {
/* Renaming .index not allowed */
error = -EBUSY;
goto exit;
}
backing_new_dentry = get_incfs_dentry(new_dentry)->backing_path.dentry;
dget(backing_old_dentry);
dget(backing_new_dentry);
@ -1918,6 +1927,7 @@ static int dir_rename(struct inode *old_dir, struct dentry *old_dentry,
dput(backing_new_dentry);
dput(backing_old_dentry);
exit:
mutex_unlock(&mi->mi_dir_struct_mutex);
if (error)
pr_debug("incfs: %s err:%d\n", __func__, error);

12
tools/testing/selftests/filesystems/incfs/incfs_test.c
View File

@ -837,6 +837,12 @@ static int cant_touch_index_test(const char *mount_dir)
goto failure;
}
err = rmdir(index_path);
if (err == 0 || errno != EBUSY) {
print_error(".index directory should not be removed\n");
goto failure;
}
err = emit_file(cmd_fd, ".index", file_name, &file_id,
file_size, NULL);
if (err != -EBUSY) {
@ -871,6 +877,12 @@ static int cant_touch_index_test(const char *mount_dir)
goto failure;
}
err = rename(index_path, dst_name);
if (err == 0 || errno != EBUSY) {
print_error("Shouldn't rename .index directory\n");
goto failure;
}
close(cmd_fd);
free(subdir);
free(index_path);