Merge tag 'erofs-for-6.18-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:

 - Add Chunhai Guo as a EROFS reviewer to get more eyes from interested
   industry vendors

 - Fix infinite loop caused by incomplete crafted zstd-compressed data
   (thanks to Robert again!)

* tag 'erofs-for-6.18-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: avoid infinite loop due to incomplete zstd-compressed data
  MAINTAINERS: erofs: add myself as reviewer

Author: torvalds

MAINTAINERS

@@ -9209,6 +9209,7 @@ R:	Yue Hu <zbestahu@gmail.com>
 R:	Jeffle Xu <jefflexu@linux.alibaba.com>
 R:	Sandeep Dhavale <dhavale@google.com>
 R:	Hongbo Li <lihongbo22@huawei.com>
+R:	Chunhai Guo <guochunhai@vivo.com>
 L:	linux-erofs@lists.ozlabs.org
 S:	Maintained
 W:	https://erofs.docs.kernel.org

fs/erofs/decompressor_zstd.c

@@ -172,7 +172,6 @@ static int z_erofs_zstd_decompress(struct z_erofs_decompress_req *rq,
 	dctx.bounce = strm->bounce;
 
 	do {
-		dctx.avail_out = out_buf.size - out_buf.pos;
 		dctx.inbuf_sz = in_buf.size;
 		dctx.inbuf_pos = in_buf.pos;
 		err = z_erofs_stream_switch_bufs(&dctx, &out_buf.dst,
@@ -188,14 +187,18 @@ static int z_erofs_zstd_decompress(struct z_erofs_decompress_req *rq,
 		in_buf.pos = dctx.inbuf_pos;
 
 		zerr = zstd_decompress_stream(stream, &out_buf, &in_buf);
-		if (zstd_is_error(zerr) || (!zerr && rq->outputsize)) {
+		dctx.avail_out = out_buf.size - out_buf.pos;
+		if (zstd_is_error(zerr) ||
+		    ((rq->outputsize + dctx.avail_out) && (!zerr || (zerr > 0 &&
+				!(rq->inputsize + in_buf.size - in_buf.pos))))) {
 			erofs_err(sb, "failed to decompress in[%u] out[%u]: %s",
 				  rq->inputsize, rq->outputsize,
-				  zerr ? zstd_get_error_name(zerr) : "unexpected end of stream");
+				  zstd_is_error(zerr) ? zstd_get_error_name(zerr) :
+					"unexpected end of stream");
 			err = -EFSCORRUPTED;
 			break;
 		}
-	} while (rq->outputsize || out_buf.pos < out_buf.size);
+	} while (rq->outputsize + dctx.avail_out);
 
 	if (dctx.kout)
 		kunmap_local(dctx.kout);