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From 40e24ccf3ec191e6f576da967a64630ca2160bfc Mon Sep 17 00:00:00 2001
From: Roman Tsisyk <roman@tsisyk.com>
Date: Fri, 23 Jun 2017 11:34:07 +0300
Subject: [PATCH] Fix possible integer overflow in mp_check()
Malformed MessagePack can cause `int k` counter overflow
inside mp_check()/mp_next().
Closes #16
Patch-Source: https://github.com/rtsisyk/msgpuck/commit/40e24ccf3ec191e6f576da967a64630ca2160bfc
---
msgpuck.h | 59 +++++++++++++++++++++++++++++-----------------------------
test/msgpuck.c | 42 ++++++++++++++++++++++++++++++++++++++++-
2 files changed, 70 insertions(+), 31 deletions(-)
diff --git a/msgpuck.h b/msgpuck.h
index e585a0f3..4ef9f148 100644
--- a/msgpuck.h
+++ b/msgpuck.h
@@ -1980,10 +1980,10 @@ enum {
};
MP_PROTO void
-mp_next_slowpath(const char **data, int k);
+mp_next_slowpath(const char **data, int64_t k);
MP_IMPL void
-mp_next_slowpath(const char **data, int k)
+mp_next_slowpath(const char **data, int64_t k)
{
for (; k > 0; k--) {
uint8_t c = mp_load_u8(data);
@@ -2056,7 +2056,7 @@ mp_next_slowpath(const char **data, int k)
MP_IMPL void
mp_next(const char **data)
{
- int k = 1;
+ int64_t k = 1;
for (; k > 0; k--) {
uint8_t c = mp_load_u8(data);
int l = mp_parser_hint[c];
@@ -2081,14 +2081,17 @@ mp_next(const char **data)
MP_IMPL int
mp_check(const char **data, const char *end)
{
- int k;
- for (k = 1; k > 0; k--) {
- if (mp_unlikely(*data >= end))
- return 1;
+#define MP_CHECK_LEN(_l) \
+ if (mp_unlikely((size_t)(end - *data) < (size_t)(_l))) \
+ return 1;
+ int64_t k;
+ for (k = 1; k > 0; k--) {
+ MP_CHECK_LEN(1);
uint8_t c = mp_load_u8(data);
int l = mp_parser_hint[c];
if (mp_likely(l >= 0)) {
+ MP_CHECK_LEN(l);
*data += l;
continue;
} else if (mp_likely(l > MP_HINT)) {
@@ -2100,71 +2103,68 @@ mp_check(const char **data, const char *end)
switch (l) {
case MP_HINT_STR_8:
/* MP_STR (8) */
- if (mp_unlikely(*data + sizeof(uint8_t) > end))
- return 1;
+ MP_CHECK_LEN(sizeof(uint8_t));
len = mp_load_u8(data);
+ MP_CHECK_LEN(len);
*data += len;
break;
case MP_HINT_STR_16:
/* MP_STR (16) */
- if (mp_unlikely(*data + sizeof(uint16_t) > end))
- return 1;
+ MP_CHECK_LEN(sizeof(uint16_t));
len = mp_load_u16(data);
+ MP_CHECK_LEN(len);
*data += len;
break;
case MP_HINT_STR_32:
/* MP_STR (32) */
- if (mp_unlikely(*data + sizeof(uint32_t) > end))
- return 1;
+ MP_CHECK_LEN(sizeof(uint32_t))
len = mp_load_u32(data);
+ MP_CHECK_LEN(len);
*data += len;
break;
case MP_HINT_ARRAY_16:
/* MP_ARRAY (16) */
- if (mp_unlikely(*data + sizeof(uint16_t) > end))
- return 1;
+ MP_CHECK_LEN(sizeof(uint16_t));
k += mp_load_u16(data);
break;
case MP_HINT_ARRAY_32:
/* MP_ARRAY (32) */
- if (mp_unlikely(*data + sizeof(uint32_t) > end))
- return 1;
+ MP_CHECK_LEN(sizeof(uint32_t));
k += mp_load_u32(data);
break;
case MP_HINT_MAP_16:
/* MP_MAP (16) */
- if (mp_unlikely(*data + sizeof(uint16_t) > end))
- return 1;
+ MP_CHECK_LEN(sizeof(uint16_t));
k += 2 * mp_load_u16(data);
break;
case MP_HINT_MAP_32:
/* MP_MAP (32) */
- if (mp_unlikely(*data + sizeof(uint32_t) > end))
- return 1;
+ MP_CHECK_LEN(sizeof(uint32_t));
k += 2 * mp_load_u32(data);
break;
case MP_HINT_EXT_8:
/* MP_EXT (8) */
- if (mp_unlikely(*data + sizeof(uint8_t) + 1 > end))
- return 1;
+ MP_CHECK_LEN(sizeof(uint8_t) + sizeof(uint8_t));
len = mp_load_u8(data);
mp_load_u8(data);
+ MP_CHECK_LEN(len);
*data += len;
break;
case MP_HINT_EXT_16:
/* MP_EXT (16) */
- if (mp_unlikely(*data + sizeof(uint16_t) + 1 > end))
+ MP_CHECK_LEN(sizeof(uint16_t) + sizeof(uint8_t));
return 1;
len = mp_load_u16(data);
mp_load_u8(data);
+ MP_CHECK_LEN(len);
*data += len;
break;
case MP_HINT_EXT_32:
/* MP_EXT (32) */
- if (mp_unlikely(*data + sizeof(uint32_t) + 1 > end))
- return 1;
- len = mp_load_u32(data);
+ MP_CHECK_LEN(sizeof(uint32_t) + sizeof(uint8_t));
+ len = mp_load_u32(data);
mp_load_u8(data);
+ MP_CHECK_LEN(len);
*data += len;
break;
default:
@@ -2172,9 +2172,8 @@ mp_check(const char **data, const char *end)
}
}
- if (mp_unlikely(*data > end))
- return 1;
-
+ assert(*data <= end);
+#undef MP_CHECK_LEN
return 0;
}
diff --git a/test/msgpuck.c b/test/msgpuck.c
index 751b9e11..9265453e 100644
--- a/test/msgpuck.c
+++ b/test/msgpuck.c
@@ -1055,9 +1055,48 @@ test_numbers()
return check_plan();
}
+static int
+test_overflow()
+{
+ plan(4);
+ header();
+
+ const char *chk;
+ char *d;
+ d = data;
+ chk = data;
+ d = mp_encode_array(d, 1);
+ d = mp_encode_array(d, UINT32_MAX);
+ is(mp_check(&chk, d), 1, "mp_check array overflow")
+
+ d = data;
+ chk = data;
+ d = mp_encode_array(d, 1);
+ d = mp_encode_map(d, UINT32_MAX);
+ is(mp_check(&chk, d), 1, "mp_check map overflow")
+
+ d = data;
+ chk = data;
+ d = mp_encode_array(d, 2);
+ d = mp_encode_str(d, "", 0);
+ d = mp_encode_strl(d, UINT32_MAX);
+ is(mp_check(&chk, d), 1, "mp_check str overflow")
+
+ d = data;
+ chk = data;
+ d = mp_encode_array(d, 2);
+ d = mp_encode_bin(d, "", 0);
+ d = mp_encode_binl(d, UINT32_MAX);
+ is(mp_check(&chk, d), 1, "mp_check bin overflow")
+
+ footer();
+ return check_plan();
+}
+
+
int main()
{
- plan(19);
+ plan(20);
test_uints();
test_ints();
test_bools();
@@ -1077,6 +1116,7 @@ int main()
test_mp_print();
test_mp_check();
test_numbers();
+ test_overflow();
return check_plan();
}
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