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Commit 206a81c1 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

lzo: properly check for overruns 



The lzo decompressor can, if given some really crazy data, possibly
overrun some variable types.  Modify the checking logic to properly
detect overruns before they happen.

Reported-by: default avatar"Don A. Bailey" <donb@securitymouse.com>
Tested-by: default avatar"Don A. Bailey" <donb@securitymouse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7171511e

lib/lzo/lzo1x_decompress_safe.c

+41 −21
Original line number Diff line number Diff line
@@ -19,11 +19,31 @@ 
#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

#define HAVE_IP(t, x)					\

	(((size_t)(ip_end - ip) >= (size_t)(t + x)) &&	\

	 (((t + x) >= t) && ((t + x) >= x)))



#define HAVE_OP(t, x)					\

	(((size_t)(op_end - op) >= (size_t)(t + x)) &&	\

	 (((t + x) >= t) && ((t + x) >= x)))



#define NEED_IP(t, x)					\

	do {						\

		if (!HAVE_IP(t, x))			\

			goto input_overrun;		\

	} while (0)



#define NEED_OP(t, x)					\

	do {						\

		if (!HAVE_OP(t, x))			\

			goto output_overrun;		\

	} while (0)



#define TEST_LB(m_pos)					\

	do {						\

		if ((m_pos) < out)			\

			goto lookbehind_overrun;	\

	} while (0)



int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,

			  unsigned char *out, size_t *out_len)
@@ -58,14 +78,14 @@ int lzo1x_decompress_safe(const unsigned char *in, size_t in_len, 
					while (unlikely(*ip == 0)) {

						t += 255;

						ip++;

						NEED_IP(1);

						NEED_IP(1, 0);

					}

					t += 15 + *ip++;

				}

				t += 3;

copy_literal_run:

#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)

				if (likely(HAVE_IP(t + 15) && HAVE_OP(t + 15))) {

				if (likely(HAVE_IP(t, 15) && HAVE_OP(t, 15))) {

					const unsigned char *ie = ip + t;

					unsigned char *oe = op + t;

					do {
@@ -81,8 +101,8 @@ copy_literal_run: 
				} else

#endif

				{

					NEED_OP(t);

					NEED_IP(t + 3);

					NEED_OP(t, 0);

					NEED_IP(t, 3);

					do {

						*op++ = *ip++;

					} while (--t > 0);
@@ -95,7 +115,7 @@ copy_literal_run: 
				m_pos -= t >> 2;

				m_pos -= *ip++ << 2;

				TEST_LB(m_pos);

				NEED_OP(2);

				NEED_OP(2, 0);

				op[0] = m_pos[0];

				op[1] = m_pos[1];

				op += 2;
@@ -119,10 +139,10 @@ copy_literal_run: 
				while (unlikely(*ip == 0)) {

					t += 255;

					ip++;

					NEED_IP(1);

					NEED_IP(1, 0);

				}

				t += 31 + *ip++;

				NEED_IP(2);

				NEED_IP(2, 0);

			}

			m_pos = op - 1;

			next = get_unaligned_le16(ip);
@@ -137,10 +157,10 @@ copy_literal_run: 
				while (unlikely(*ip == 0)) {

					t += 255;

					ip++;

					NEED_IP(1);

					NEED_IP(1, 0);

				}

				t += 7 + *ip++;

				NEED_IP(2);

				NEED_IP(2, 0);

			}

			next = get_unaligned_le16(ip);

			ip += 2;
@@ -154,7 +174,7 @@ copy_literal_run: 
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)

		if (op - m_pos >= 8) {

			unsigned char *oe = op + t;

			if (likely(HAVE_OP(t + 15))) {

			if (likely(HAVE_OP(t, 15))) {

				do {

					COPY8(op, m_pos);

					op += 8;
@@ -164,7 +184,7 @@ copy_literal_run: 
					m_pos += 8;

				} while (op < oe);

				op = oe;

				if (HAVE_IP(6)) {

				if (HAVE_IP(6, 0)) {

					state = next;

					COPY4(op, ip);

					op += next;
@@ -172,7 +192,7 @@ copy_literal_run: 
					continue;

				}

			} else {

				NEED_OP(t);

				NEED_OP(t, 0);

				do {

					*op++ = *m_pos++;

				} while (op < oe);
@@ -181,7 +201,7 @@ copy_literal_run: 
#endif

		{

			unsigned char *oe = op + t;

			NEED_OP(t);

			NEED_OP(t, 0);

			op[0] = m_pos[0];

			op[1] = m_pos[1];

			op += 2;
@@ -194,15 +214,15 @@ match_next: 
		state = next;

		t = next;

#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)

		if (likely(HAVE_IP(6) && HAVE_OP(4))) {

		if (likely(HAVE_IP(6, 0) && HAVE_OP(4, 0))) {

			COPY4(op, ip);

			op += t;

			ip += t;

		} else

#endif

		{

			NEED_IP(t + 3);

			NEED_OP(t);

			NEED_IP(t, 3);

			NEED_OP(t, 0);

			while (t > 0) {

				*op++ = *ip++;

				t--;