From 1e8c8e5e43f2c34c0f692b444e0ad06825b8a3dd Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers3@gmail.com>
Date: Sat, 30 May 2015 15:48:03 -0500
Subject: [PATCH] Require size_in_wim == uncompressed_size for uncompressed
 resources

It required quite a bit of extra code to handle this case, which really
should just be considered invalid.
---
 src/blob_table.c | 26 ++++++----------------
 src/resource.c   | 56 +++---------------------------------------------
 2 files changed, 9 insertions(+), 73 deletions(-)

diff --git a/src/blob_table.c b/src/blob_table.c
index 08859c42..4ec6cd93 100644
--- a/src/blob_table.c
+++ b/src/blob_table.c
@@ -953,27 +953,13 @@ read_blob_table(WIMStruct *wim)
 					goto out;
 			}
 
-			/* How to handle an uncompressed resource with its
-			 * uncompressed size different from its compressed size?
-			 *
-			 * Based on a simple test, WIMGAPI seems to handle this
-			 * as follows:
-			 *
-			 * if (size_in_wim > uncompressed_size) {
-			 *	Ignore uncompressed_size; use size_in_wim
-			 *	instead.
-			 * } else {
-			 *	Honor uncompressed_size, but treat the part of
-			 *	the file data above size_in_wim as all zeros.
-			 * }
-			 *
-			 * So we will do the same.  */
-			if (unlikely(!(reshdr.flags &
-				       WIM_RESHDR_FLAG_COMPRESSED) &&
-				     (reshdr.size_in_wim >
-				      reshdr.uncompressed_size)))
+			if (unlikely(!(reshdr.flags & WIM_RESHDR_FLAG_COMPRESSED) &&
+				     (reshdr.size_in_wim != reshdr.uncompressed_size)))
 			{
-				reshdr.uncompressed_size = reshdr.size_in_wim;
+				ERROR("Uncompressed resource has "
+				      "size_in_wim != uncompressed_size");
+				ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
+				goto out;
 			}
 
 			/* Set up a resource descriptor for this blob.  */
diff --git a/src/resource.c b/src/resource.c
index 13482197..e2a39991 100644
--- a/src/resource.c
+++ b/src/resource.c
@@ -554,28 +554,6 @@ read_error:
 	goto out_free_memory;
 }
 
-static int
-fill_zeroes(u64 size, consume_data_callback_t cb, void *cb_ctx)
-{
-	if (unlikely(size)) {
-		u8 buf[min(size, BUFFER_SIZE)];
-
-		memset(buf, 0, sizeof(buf));
-
-		do {
-			size_t len;
-			int ret;
-
-			len = min(size, BUFFER_SIZE);
-			ret = cb(buf, len, cb_ctx);
-			if (ret)
-				return ret;
-			size -= len;
-		} while (size);
-	}
-	return 0;
-}
-
 /* Read raw data from a file descriptor at the specified offset, feeding the
  * data it in chunks into the specified callback function.  */
 static int
@@ -668,37 +646,9 @@ read_partial_wim_resource(const struct wim_resource_descriptor *rdesc,
 		return read_compressed_wim_resource(rdesc, &range, 1,
 						    cb, cb_ctx);
 	} else {
-		/* Reading uncompressed resource.  For completeness, handle the
-		 * weird case where size_in_wim < uncompressed_size.  */
-
-		u64 read_size;
-		u64 zeroes_size;
-		int ret;
-
-		if (likely(offset + size <= rdesc->size_in_wim) ||
-		    rdesc->is_pipable)
-		{
-			read_size = size;
-			zeroes_size = 0;
-		} else {
-			if (offset >= rdesc->size_in_wim) {
-				read_size = 0;
-				zeroes_size = size;
-			} else {
-				read_size = rdesc->size_in_wim - offset;
-				zeroes_size = offset + size - rdesc->size_in_wim;
-			}
-		}
-
-		ret = read_raw_file_data(&rdesc->wim->in_fd,
-					 rdesc->offset_in_wim + offset,
-					 read_size,
-					 cb,
-					 cb_ctx);
-		if (ret)
-			return ret;
-
-		return fill_zeroes(zeroes_size, cb, cb_ctx);
+		return read_raw_file_data(&rdesc->wim->in_fd,
+					  rdesc->offset_in_wim + offset,
+					  size, cb, cb_ctx);
 	}
 }
 
-- 
2.43.0