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-rw-r--r--lib/lzo/lzo1x_decompress_safe.c296
1 files changed, 296 insertions, 0 deletions
diff --git a/lib/lzo/lzo1x_decompress_safe.c b/lib/lzo/lzo1x_decompress_safe.c
new file mode 100644
index 000000000..7892a40cf
--- /dev/null
+++ b/lib/lzo/lzo1x_decompress_safe.c
@@ -0,0 +1,296 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LZO1X Decompressor from LZO
+ *
+ * Copyright (C) 1996-2012 Markus F.X.J. Oberhumer <markus@oberhumer.com>
+ *
+ * The full LZO package can be found at:
+ * http://www.oberhumer.com/opensource/lzo/
+ *
+ * Changed for Linux kernel use by:
+ * Nitin Gupta <nitingupta910@gmail.com>
+ * Richard Purdie <rpurdie@openedhand.com>
+ */
+
+#ifndef STATIC
+#include <linux/module.h>
+#include <linux/kernel.h>
+#endif
+#include <asm/unaligned.h>
+#include <linux/lzo.h>
+#include "lzodefs.h"
+
+#define HAVE_IP(x) ((size_t)(ip_end - ip) >= (size_t)(x))
+#define HAVE_OP(x) ((size_t)(op_end - op) >= (size_t)(x))
+#define NEED_IP(x) if (!HAVE_IP(x)) goto input_overrun
+#define NEED_OP(x) if (!HAVE_OP(x)) goto output_overrun
+#define TEST_LB(m_pos) if ((m_pos) < out) goto lookbehind_overrun
+
+/* This MAX_255_COUNT is the maximum number of times we can add 255 to a base
+ * count without overflowing an integer. The multiply will overflow when
+ * multiplying 255 by more than MAXINT/255. The sum will overflow earlier
+ * depending on the base count. Since the base count is taken from a u8
+ * and a few bits, it is safe to assume that it will always be lower than
+ * or equal to 2*255, thus we can always prevent any overflow by accepting
+ * two less 255 steps. See Documentation/staging/lzo.rst for more information.
+ */
+#define MAX_255_COUNT ((((size_t)~0) / 255) - 2)
+
+int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
+ unsigned char *out, size_t *out_len)
+{
+ unsigned char *op;
+ const unsigned char *ip;
+ size_t t, next;
+ size_t state = 0;
+ const unsigned char *m_pos;
+ const unsigned char * const ip_end = in + in_len;
+ unsigned char * const op_end = out + *out_len;
+
+ unsigned char bitstream_version;
+
+ op = out;
+ ip = in;
+
+ if (unlikely(in_len < 3))
+ goto input_overrun;
+
+ if (likely(in_len >= 5) && likely(*ip == 17)) {
+ bitstream_version = ip[1];
+ ip += 2;
+ } else {
+ bitstream_version = 0;
+ }
+
+ if (*ip > 17) {
+ t = *ip++ - 17;
+ if (t < 4) {
+ next = t;
+ goto match_next;
+ }
+ goto copy_literal_run;
+ }
+
+ for (;;) {
+ t = *ip++;
+ if (t < 16) {
+ if (likely(state == 0)) {
+ if (unlikely(t == 0)) {
+ size_t offset;
+ const unsigned char *ip_last = ip;
+
+ while (unlikely(*ip == 0)) {
+ ip++;
+ NEED_IP(1);
+ }
+ offset = ip - ip_last;
+ if (unlikely(offset > MAX_255_COUNT))
+ return LZO_E_ERROR;
+
+ offset = (offset << 8) - offset;
+ t += offset + 15 + *ip++;
+ }
+ t += 3;
+copy_literal_run:
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+ if (likely(HAVE_IP(t + 15) && HAVE_OP(t + 15))) {
+ const unsigned char *ie = ip + t;
+ unsigned char *oe = op + t;
+ do {
+ COPY8(op, ip);
+ op += 8;
+ ip += 8;
+ COPY8(op, ip);
+ op += 8;
+ ip += 8;
+ } while (ip < ie);
+ ip = ie;
+ op = oe;
+ } else
+#endif
+ {
+ NEED_OP(t);
+ NEED_IP(t + 3);
+ do {
+ *op++ = *ip++;
+ } while (--t > 0);
+ }
+ state = 4;
+ continue;
+ } else if (state != 4) {
+ next = t & 3;
+ m_pos = op - 1;
+ m_pos -= t >> 2;
+ m_pos -= *ip++ << 2;
+ TEST_LB(m_pos);
+ NEED_OP(2);
+ op[0] = m_pos[0];
+ op[1] = m_pos[1];
+ op += 2;
+ goto match_next;
+ } else {
+ next = t & 3;
+ m_pos = op - (1 + M2_MAX_OFFSET);
+ m_pos -= t >> 2;
+ m_pos -= *ip++ << 2;
+ t = 3;
+ }
+ } else if (t >= 64) {
+ next = t & 3;
+ m_pos = op - 1;
+ m_pos -= (t >> 2) & 7;
+ m_pos -= *ip++ << 3;
+ t = (t >> 5) - 1 + (3 - 1);
+ } else if (t >= 32) {
+ t = (t & 31) + (3 - 1);
+ if (unlikely(t == 2)) {
+ size_t offset;
+ const unsigned char *ip_last = ip;
+
+ while (unlikely(*ip == 0)) {
+ ip++;
+ NEED_IP(1);
+ }
+ offset = ip - ip_last;
+ if (unlikely(offset > MAX_255_COUNT))
+ return LZO_E_ERROR;
+
+ offset = (offset << 8) - offset;
+ t += offset + 31 + *ip++;
+ NEED_IP(2);
+ }
+ m_pos = op - 1;
+ next = get_unaligned_le16(ip);
+ ip += 2;
+ m_pos -= next >> 2;
+ next &= 3;
+ } else {
+ NEED_IP(2);
+ next = get_unaligned_le16(ip);
+ if (((next & 0xfffc) == 0xfffc) &&
+ ((t & 0xf8) == 0x18) &&
+ likely(bitstream_version)) {
+ NEED_IP(3);
+ t &= 7;
+ t |= ip[2] << 3;
+ t += MIN_ZERO_RUN_LENGTH;
+ NEED_OP(t);
+ memset(op, 0, t);
+ op += t;
+ next &= 3;
+ ip += 3;
+ goto match_next;
+ } else {
+ m_pos = op;
+ m_pos -= (t & 8) << 11;
+ t = (t & 7) + (3 - 1);
+ if (unlikely(t == 2)) {
+ size_t offset;
+ const unsigned char *ip_last = ip;
+
+ while (unlikely(*ip == 0)) {
+ ip++;
+ NEED_IP(1);
+ }
+ offset = ip - ip_last;
+ if (unlikely(offset > MAX_255_COUNT))
+ return LZO_E_ERROR;
+
+ offset = (offset << 8) - offset;
+ t += offset + 7 + *ip++;
+ NEED_IP(2);
+ next = get_unaligned_le16(ip);
+ }
+ ip += 2;
+ m_pos -= next >> 2;
+ next &= 3;
+ if (m_pos == op)
+ goto eof_found;
+ m_pos -= 0x4000;
+ }
+ }
+ TEST_LB(m_pos);
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+ if (op - m_pos >= 8) {
+ unsigned char *oe = op + t;
+ if (likely(HAVE_OP(t + 15))) {
+ do {
+ COPY8(op, m_pos);
+ op += 8;
+ m_pos += 8;
+ COPY8(op, m_pos);
+ op += 8;
+ m_pos += 8;
+ } while (op < oe);
+ op = oe;
+ if (HAVE_IP(6)) {
+ state = next;
+ COPY4(op, ip);
+ op += next;
+ ip += next;
+ continue;
+ }
+ } else {
+ NEED_OP(t);
+ do {
+ *op++ = *m_pos++;
+ } while (op < oe);
+ }
+ } else
+#endif
+ {
+ unsigned char *oe = op + t;
+ NEED_OP(t);
+ op[0] = m_pos[0];
+ op[1] = m_pos[1];
+ op += 2;
+ m_pos += 2;
+ do {
+ *op++ = *m_pos++;
+ } while (op < oe);
+ }
+match_next:
+ state = next;
+ t = next;
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+ if (likely(HAVE_IP(6) && HAVE_OP(4))) {
+ COPY4(op, ip);
+ op += t;
+ ip += t;
+ } else
+#endif
+ {
+ NEED_IP(t + 3);
+ NEED_OP(t);
+ while (t > 0) {
+ *op++ = *ip++;
+ t--;
+ }
+ }
+ }
+
+eof_found:
+ *out_len = op - out;
+ return (t != 3 ? LZO_E_ERROR :
+ ip == ip_end ? LZO_E_OK :
+ ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN);
+
+input_overrun:
+ *out_len = op - out;
+ return LZO_E_INPUT_OVERRUN;
+
+output_overrun:
+ *out_len = op - out;
+ return LZO_E_OUTPUT_OVERRUN;
+
+lookbehind_overrun:
+ *out_len = op - out;
+ return LZO_E_LOOKBEHIND_OVERRUN;
+}
+#ifndef STATIC
+EXPORT_SYMBOL_GPL(lzo1x_decompress_safe);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZO1X Decompressor");
+
+#endif
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