1 files changed, 251 insertions, 0 deletions
diff --git a/drivers/staging/erofs/unzip_lz4.c b/drivers/staging/erofs/unzip_lz4.c
new file mode 100644
index 000000000000..b1ea23f66c4e
--- /dev/null
+++ b/drivers/staging/erofs/unzip_lz4.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * linux/drivers/staging/erofs/unzip_lz4.c
+ *
+ * Copyright (C) 2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ *
+ * Original code taken from 'linux/lib/lz4/lz4_decompress.c'
+ */
+
+/*
+ * LZ4 - Fast LZ compression algorithm
+ * Copyright (C) 2011 - 2016, Yann Collet.
+ * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php)
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *	* Redistributions of source code must retain the above copyright
+ *	  notice, this list of conditions and the following disclaimer.
+ *	* Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * You can contact the author at :
+ *	- LZ4 homepage : http://www.lz4.org
+ *	- LZ4 source repository : https://github.com/lz4/lz4
+ *
+ *	Changed for kernel usage by:
+ *	Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
+ */
+#include "internal.h"
+#include <asm/unaligned.h>
+#include "lz4defs.h"
+
+/*
+ * no public solution to solve our requirement yet.
+ * see: <required buffer size for LZ4_decompress_safe_partial>
+ *      https://groups.google.com/forum/#!topic/lz4c/_3kkz5N6n00
+ */
+static FORCE_INLINE int customized_lz4_decompress_safe_partial(
+	const void * const source,
+	void * const dest,
+	int inputSize,
+	int outputSize)
+{
+	/* Local Variables */
+	const BYTE *ip = (const BYTE *) source;
+	const BYTE * const iend = ip + inputSize;
+
+	BYTE *op = (BYTE *) dest;
+	BYTE * const oend = op + outputSize;
+	BYTE *cpy;
+
+	static const unsigned int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };
+	static const int dec64table[] = { 0, 0, 0, -1, 0, 1, 2, 3 };
+
+	/* Empty output buffer */
+	if (unlikely(outputSize == 0))
+		return ((inputSize == 1) && (*ip == 0)) ? 0 : -1;
+
+	/* Main Loop : decode sequences */
+	while (1) {
+		size_t length;
+		const BYTE *match;
+		size_t offset;
+
+		/* get literal length */
+		unsigned int const token = *ip++;
+
+		length = token>>ML_BITS;
+
+		if (length == RUN_MASK) {
+			unsigned int s;
+
+			do {
+				s = *ip++;
+				length += s;
+			} while ((ip < iend - RUN_MASK) & (s == 255));
+
+			if (unlikely((size_t)(op + length) < (size_t)(op))) {
+				/* overflow detection */
+				goto _output_error;
+			}
+			if (unlikely((size_t)(ip + length) < (size_t)(ip))) {
+				/* overflow detection */
+				goto _output_error;
+			}
+		}
+
+		/* copy literals */
+		cpy = op + length;
+		if ((cpy > oend - WILDCOPYLENGTH) ||
+			(ip + length > iend - (2 + 1 + LASTLITERALS))) {
+			if (cpy > oend) {
+				memcpy(op, ip, length = oend - op);
+				op += length;
+				break;
+			}
+
+			if (unlikely(ip + length > iend)) {
+				/*
+				 * Error :
+				 * read attempt beyond
+				 * end of input buffer
+				 */
+				goto _output_error;
+			}
+
+			memcpy(op, ip, length);
+			ip += length;
+			op += length;
+
+			if (ip > iend - 2)
+				break;
+			/* Necessarily EOF, due to parsing restrictions */
+			/* break; */
+		} else {
+			LZ4_wildCopy(op, ip, cpy);
+			ip += length;
+			op = cpy;
+		}
+
+		/* get offset */
+		offset = LZ4_readLE16(ip);
+		ip += 2;
+		match = op - offset;
+
+		if (unlikely(match < (const BYTE *)dest)) {
+			/* Error : offset outside buffers */
+			goto _output_error;
+		}
+
+		/* get matchlength */
+		length = token & ML_MASK;
+		if (length == ML_MASK) {
+			unsigned int s;
+
+			do {
+				s = *ip++;
+
+				if (ip > iend - LASTLITERALS)
+					goto _output_error;
+
+				length += s;
+			} while (s == 255);
+
+			if (unlikely((size_t)(op + length) < (size_t)op)) {
+				/* overflow detection */
+				goto _output_error;
+			}
+		}
+
+		length += MINMATCH;
+
+		/* copy match within block */
+		cpy = op + length;
+
+		if (unlikely(cpy >= oend - WILDCOPYLENGTH)) {
+			if (cpy >= oend) {
+				while (op < oend)
+					*op++ = *match++;
+				break;
+			}
+			goto __match;
+		}
+
+		/* costs ~1%; silence an msan warning when offset == 0 */
+		LZ4_write32(op, (U32)offset);
+
+		if (unlikely(offset < 8)) {
+			const int dec64 = dec64table[offset];
+
+			op[0] = match[0];
+			op[1] = match[1];
+			op[2] = match[2];
+			op[3] = match[3];
+			match += dec32table[offset];
+			memcpy(op + 4, match, 4);
+			match -= dec64;
+		} else {
+			LZ4_copy8(op, match);
+			match += 8;
+		}
+
+		op += 8;
+
+		if (unlikely(cpy > oend - 12)) {
+			BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
+
+			if (op < oCopyLimit) {
+				LZ4_wildCopy(op, match, oCopyLimit);
+				match += oCopyLimit - op;
+				op = oCopyLimit;
+			}
+__match:
+			while (op < cpy)
+				*op++ = *match++;
+		} else {
+			LZ4_copy8(op, match);
+
+			if (length > 16)
+				LZ4_wildCopy(op + 8, match + 8, cpy);
+		}
+
+		op = cpy; /* correction */
+	}
+	DBG_BUGON((void *)ip - source > inputSize);
+	DBG_BUGON((void *)op - dest > outputSize);
+
+	/* Nb of output bytes decoded */
+	return (int) ((void *)op - dest);
+
+	/* Overflow error detected */
+_output_error:
+	return -ERANGE;
+}
+
+int z_erofs_unzip_lz4(void *in, void *out, size_t inlen, size_t outlen)
+{
+	int ret = customized_lz4_decompress_safe_partial(in,
+		out, inlen, outlen);
+
+	if (ret >= 0)
+		return ret;
+
+	/*
+	 * LZ4_decompress_safe will return an error code
+	 * (< 0) if decompression failed
+	 */
+	errln("%s, failed to decompress, in[%p, %zu] outlen[%p, %zu]",
+	      __func__, in, inlen, out, outlen);
+	WARN_ON(1);
+	print_hex_dump(KERN_DEBUG, "raw data [in]: ", DUMP_PREFIX_OFFSET,
+		16, 1, in, inlen, true);
+	print_hex_dump(KERN_DEBUG, "raw data [out]: ", DUMP_PREFIX_OFFSET,
+		16, 1, out, outlen, true);
+	return -EIO;
+}
+