staging: erofs: some compressed cluster should be submitted for corrupted images

commit ee45197c807895e156b2be0abcaebdfc116487c8 upstream.

As reported by erofs_utils fuzzer, a logical page can belong
to at most 2 compressed clusters, if one compressed cluster
is corrupted, but the other has been ready in submitting chain.

The chain needs to submit anyway in order to keep the page
working properly (page unlocked with PG_error set, PG_uptodate
not set).

Let's fix it now.

Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
Cc: <stable@vger.kernel.org> # 4.19+
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20190819103426.87579-2-gaoxiang25@huawei.com
[ Gao Xiang: Manually backport to v4.19.y stable. ]
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
index ad6fe6d9d00abe33e816e9efded5eb0fda0818e6..fc44f5ce670bdfaf8bbe24d6bac18f862d7c9db4 100644 (file)
--- a/drivers/staging/erofs/unzip_vle.c
+++ b/drivers/staging/erofs/unzip_vle.c
@@ -1335,19 +1335,18 @@ static int z_erofs_vle_normalaccess_readpage(struct file *file,
        err = z_erofs_do_read_page(&f, page, &pagepool);
        (void)z_erofs_vle_work_iter_end(&f.builder);
 
-       if (err) {
+       /* if some compressed cluster ready, need submit them anyway */
+       z_erofs_submit_and_unzip(&f, &pagepool, true);
+
+       if (err)
                errln("%s, failed to read, err [%d]", __func__, err);
-               goto out;
-       }
 
-       z_erofs_submit_and_unzip(&f, &pagepool, true);
-out:
        if (f.m_iter.mpage != NULL)
                put_page(f.m_iter.mpage);
 
        /* clean up the remaining free pages */
        put_pages_list(&pagepool);
-       return 0;
+       return err;
 }
 
 static inline int __z_erofs_vle_normalaccess_readpages(