1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
https://roy.marples.name/git/dhcpcd.git/patch/?id=23525884a346ed81c808c1ed90e3c56a8bf0cc68
From 8d11b33f6c60e2db257130fa383ba76b6018bcf6 Mon Sep 17 00:00:00 2001
From: Roy Marples <roy@marples.name>
Date: Fri, 19 Apr 2019 09:45:02 +0100
Subject: DHCPv6: Fix a potential buffer overflow reading NA/TA addresses
Only copy upto the size of the address option rather than the
option length.
Found by Maxime Villard <max@m00nbsd.net>
---
src/dhcp6.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/dhcp6.c b/src/dhcp6.c
index 99a452b..8fc4f00 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -2029,12 +2029,12 @@ dhcp6_findna(struct interface *ifp, uint16_t ot, const uint8_t *iaid,
nd = o + ol;
l -= (size_t)(nd - d);
d = nd;
- if (ol < 24) {
+ if (ol < sizeof(ia)) {
errno = EINVAL;
logerrx("%s: IA Address option truncated", ifp->name);
continue;
}
- memcpy(&ia, o, ol);
+ memcpy(&ia, o, sizeof(ia));
ia.pltime = ntohl(ia.pltime);
ia.vltime = ntohl(ia.vltime);
/* RFC 3315 22.6 */
--
cgit v1.1
From 4b67f6f1038fd4ad5ca7734eaaeba1b2ec4816b8 Mon Sep 17 00:00:00 2001
From: Roy Marples <roy@marples.name>
Date: Fri, 19 Apr 2019 21:00:19 +0100
Subject: DHCP: Fix a potential 1 byte read overflow with DHO_OPTSOVERLOADED
This fix basically moves the option length check up and also
corrects an off by one error with it.
Thanks to Maxime Villard <max@m00nbsd.net>
---
src/dhcp.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/src/dhcp.c b/src/dhcp.c
index f7cdefc..e13d1b4 100644
--- a/src/dhcp.c
+++ b/src/dhcp.c
@@ -215,6 +215,12 @@ get_option(struct dhcpcd_ctx *ctx,
}
l = *p++;
+ /* Check we can read the option data, if present */
+ if (p + l > e) {
+ errno = EINVAL;
+ return NULL;
+ }
+
if (o == DHO_OPTSOVERLOADED) {
/* Ensure we only get this option once by setting
* the last bit as well as the value.
@@ -249,10 +255,6 @@ get_option(struct dhcpcd_ctx *ctx,
bp += ol;
}
ol = l;
- if (p + ol >= e) {
- errno = EINVAL;
- return NULL;
- }
op = p;
bl += ol;
}
--
cgit v1.1
From 7121040790b611ca3fbc400a1bbcd4364ef57233 Mon Sep 17 00:00:00 2001
From: Roy Marples <roy@marples.name>
Date: Fri, 19 Apr 2019 21:40:14 +0100
Subject: auth: Use consttime_memequal(3) to compare hashes
This stops any attacker from trying to infer secrets from latency.
Thanks to Maxime Villard <max@m00nbsd.net>
---
src/auth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/auth.c b/src/auth.c
index 9e24998..ce97051 100644
--- a/src/auth.c
+++ b/src/auth.c
@@ -354,7 +354,7 @@ gottoken:
}
free(mm);
- if (memcmp(d, &hmac_code, dlen)) {
+ if (!consttime_memequal(d, &hmac_code, dlen)) {
errno = EPERM;
return NULL;
}
--
cgit v1.1
From cfde89ab66cb4e5957b1c4b68ad6a9449e2784da Mon Sep 17 00:00:00 2001
From: Roy Marples <roy@marples.name>
Date: Fri, 19 Apr 2019 21:42:07 +0100
Subject: compat: Provide consttime_memequal if not in libc
Public domain version by Matthias Drochner <drochner@netbsd.org>
---
configure | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/configure b/configure
index 570e65f..4f58f0f 100755
--- a/configure
+++ b/configure
@@ -13,6 +13,7 @@ IPV4LL=
INET6=
ARC4RANDOM=
CLOSEFROM=
+CONSTTIME_MEMEQUAL=
STRLCPY=
UDEV=
OS=
@@ -846,6 +847,27 @@ if [ "$STRTOI" = no ]; then
echo "#include \"compat/strtoi.h\"" >>$CONFIG_H
fi
+if [ -z "$CONSTTIME_MEMEQUAL" ]; then
+ printf "Testing for consttime_memequal ... "
+ cat <<EOF >_consttime_memequal.c
+#include <string.h>
+int main(void) {
+ return consttime_memequal("deadbeef", "deadbeef", 8);
+}
+EOF
+ if $XCC _consttime_memequal.c -o _consttime_memequal 2>&3; then
+ CONSTTIME_MEMEQUAL=yes
+ else
+ CONSTTIME_MEMEQUAL=no
+ fi
+ echo "$CONSTTIME_MEMEQUAL"
+ rm -f _consttime_memequal.c _consttime_memequal
+fi
+if [ "$CONSTTIME_MEMEQUAL" = no ]; then
+ echo "#include \"compat/consttime_memequal.h\"" \
+ >>$CONFIG_H
+fi
+
if [ -z "$DPRINTF" ]; then
printf "Testing for dprintf ... "
cat <<EOF >_dprintf.c
--
cgit v1.1
From aee631aadeef4283c8a749c1caf77823304acf5e Mon Sep 17 00:00:00 2001
From: Roy Marples <roy@marples.name>
Date: Fri, 19 Apr 2019 21:47:37 +0100
Subject: Really add consttime_memequal
---
compat/consttime_memequal.h | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
create mode 100644 compat/consttime_memequal.h
diff --git a/compat/consttime_memequal.h b/compat/consttime_memequal.h
new file mode 100644
index 0000000..9830648
--- /dev/null
+++ b/compat/consttime_memequal.h
@@ -0,0 +1,28 @@
+/*
+ * Written by Matthias Drochner <drochner@NetBSD.org>.
+ * Public domain.
+ */
+
+#ifndef CONSTTIME_MEMEQUAL_H
+#define CONSTTIME_MEMEQUAL_H
+inline static int
+consttime_memequal(const void *b1, const void *b2, size_t len)
+{
+ const unsigned char *c1 = b1, *c2 = b2;
+ unsigned int res = 0;
+
+ while (len--)
+ res |= *c1++ ^ *c2++;
+
+ /*
+ * Map 0 to 1 and [1, 256) to 0 using only constant-time
+ * arithmetic.
+ *
+ * This is not simply `!res' because although many CPUs support
+ * branchless conditional moves and many compilers will take
+ * advantage of them, certain compilers generate branches on
+ * certain CPUs for `!res'.
+ */
+ return (1 & ((res - 1) >> 8));
+}
+#endif /* CONSTTIME_MEMEQUAL_H */
--
cgit v1.1
|
GitWeb