[PATCH v2 1/2] Revert "lzo: properly check for overruns"

[Stefan Müller-Klieser]

This reverts barebox commit ecb1dc0b1e859bca9
This corresponds to kernel commit af958a38a60c7ca3d8

As analysed by Willem Pinckaers, this fix is still incomplete on
certain rare corner cases, and it is easier to restart from the
original code.

Reported-by: Willem Pinckaers <willem at lekkertech.net>
Cc: "Don A. Bailey" <donb at securitymouse.com>
Cc: stable <stable at vger.kernel.org>
Signed-off-by: Willy Tarreau <w at 1wt.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Stefan Müller-Klieser <s.mueller-klieser at phytec.de>
---
 lib/lzo/lzo1x_decompress_safe.c | 64 ++++++++++++++---------------------------
 1 file changed, 22 insertions(+), 42 deletions(-)

diff --git a/lib/lzo/lzo1x_decompress_safe.c b/lib/lzo/lzo1x_decompress_safe.c
index 48bedba..de795a3 100644
--- a/lib/lzo/lzo1x_decompress_safe.c
+++ b/lib/lzo/lzo1x_decompress_safe.c
@@ -16,34 +16,14 @@
 #include <lzo.h>
 #include "lzodefs.h"
 
-#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)
+#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
 
 int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
-			  unsigned char *out, size_t *out_len)
+			unsigned char *out, size_t *out_len)
 {
 	unsigned char *op;
 	const unsigned char *ip;
@@ -75,14 +55,14 @@ int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
 					while (unlikely(*ip == 0)) {
 						t += 255;
 						ip++;
-						NEED_IP(1, 0);
+						NEED_IP(1);
 					}
 					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 {
@@ -98,8 +78,8 @@ copy_literal_run:
 				} else
 #endif
 				{
-					NEED_OP(t, 0);
-					NEED_IP(t, 3);
+					NEED_OP(t);
+					NEED_IP(t + 3);
 					do {
 						*op++ = *ip++;
 					} while (--t > 0);
@@ -112,7 +92,7 @@ copy_literal_run:
 				m_pos -= t >> 2;
 				m_pos -= *ip++ << 2;
 				TEST_LB(m_pos);
-				NEED_OP(2, 0);
+				NEED_OP(2);
 				op[0] = m_pos[0];
 				op[1] = m_pos[1];
 				op += 2;
@@ -136,10 +116,10 @@ copy_literal_run:
 				while (unlikely(*ip == 0)) {
 					t += 255;
 					ip++;
-					NEED_IP(1, 0);
+					NEED_IP(1);
 				}
 				t += 31 + *ip++;
-				NEED_IP(2, 0);
+				NEED_IP(2);
 			}
 			m_pos = op - 1;
 			next = get_unaligned_le16(ip);
@@ -154,10 +134,10 @@ copy_literal_run:
 				while (unlikely(*ip == 0)) {
 					t += 255;
 					ip++;
-					NEED_IP(1, 0);
+					NEED_IP(1);
 				}
 				t += 7 + *ip++;
-				NEED_IP(2, 0);
+				NEED_IP(2);
 			}
 			next = get_unaligned_le16(ip);
 			ip += 2;
@@ -171,7 +151,7 @@ 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;
@@ -181,7 +161,7 @@ copy_literal_run:
 					m_pos += 8;
 				} while (op < oe);
 				op = oe;
-				if (HAVE_IP(6, 0)) {
+				if (HAVE_IP(6)) {
 					state = next;
 					COPY4(op, ip);
 					op += next;
@@ -189,7 +169,7 @@ copy_literal_run:
 					continue;
 				}
 			} else {
-				NEED_OP(t, 0);
+				NEED_OP(t);
 				do {
 					*op++ = *m_pos++;
 				} while (op < oe);
@@ -198,7 +178,7 @@ copy_literal_run:
 #endif
 		{
 			unsigned char *oe = op + t;
-			NEED_OP(t, 0);
+			NEED_OP(t);
 			op[0] = m_pos[0];
 			op[1] = m_pos[1];
 			op += 2;
@@ -211,15 +191,15 @@ match_next:
 		state = next;
 		t = next;
 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
-		if (likely(HAVE_IP(6, 0) && HAVE_OP(4, 0))) {
+		if (likely(HAVE_IP(6) && HAVE_OP(4))) {
 			COPY4(op, ip);
 			op += t;
 			ip += t;
 		} else
 #endif
 		{
-			NEED_IP(t, 3);
-			NEED_OP(t, 0);
+			NEED_IP(t + 3);
+			NEED_OP(t);
 			while (t > 0) {
 				*op++ = *ip++;
 				t--;
-- 
1.9.1