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authorMark Brown <broonie@kernel.org>2014-10-31 09:44:21 +0000
committerMark Brown <broonie@kernel.org>2014-10-31 09:44:21 +0000
commitff114805e1dc9b64c1f2e02fbb07a6ed309b18d8 (patch)
tree64407a783525686b864b3cd56292bf7e9d67d507 /lib
parentbfbceba4d4e9a3a538a80a1a0af18db55c9924a4 (diff)
parent816b571ac0e9eb9700df1ebc99702f9ad04e8607 (diff)
downloadlinux-linaro-stable-ff114805e1dc9b64c1f2e02fbb07a6ed309b18d8.tar.gz
Merge tag 'v3.10.59' into linux-linaro-lsk
This is the 3.10.59 stable release
Diffstat (limited to 'lib')
-rw-r--r--lib/lzo/lzo1x_decompress_safe.c103
1 files changed, 57 insertions, 46 deletions
diff --git a/lib/lzo/lzo1x_decompress_safe.c b/lib/lzo/lzo1x_decompress_safe.c
index 8563081e8da3..a1c387f6afba 100644
--- a/lib/lzo/lzo1x_decompress_safe.c
+++ b/lib/lzo/lzo1x_decompress_safe.c
@@ -19,31 +19,21 @@
#include <linux/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_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_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)
+/* 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/lzo.txt 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)
@@ -75,17 +65,24 @@ int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
if (t < 16) {
if (likely(state == 0)) {
if (unlikely(t == 0)) {
+ size_t offset;
+ const unsigned char *ip_last = ip;
+
while (unlikely(*ip == 0)) {
- t += 255;
ip++;
- NEED_IP(1, 0);
+ NEED_IP(1);
}
- t += 15 + *ip++;
+ 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))) {
+ if (likely(HAVE_IP(t + 15) && HAVE_OP(t + 15))) {
const unsigned char *ie = ip + t;
unsigned char *oe = op + t;
do {
@@ -101,8 +98,8 @@ 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);
@@ -115,7 +112,7 @@ 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;
@@ -136,13 +133,20 @@ copy_literal_run:
} 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)) {
- t += 255;
ip++;
- NEED_IP(1, 0);
+ NEED_IP(1);
}
- t += 31 + *ip++;
- NEED_IP(2, 0);
+ 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);
@@ -154,13 +158,20 @@ copy_literal_run:
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)) {
- t += 255;
ip++;
- NEED_IP(1, 0);
+ NEED_IP(1);
}
- t += 7 + *ip++;
- NEED_IP(2, 0);
+ 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;
@@ -174,7 +185,7 @@ 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;
@@ -184,7 +195,7 @@ 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;
@@ -192,7 +203,7 @@ copy_literal_run:
continue;
}
} else {
- NEED_OP(t, 0);
+ NEED_OP(t);
do {
*op++ = *m_pos++;
} while (op < oe);
@@ -201,7 +212,7 @@ 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;
@@ -214,15 +225,15 @@ 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--;