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
|
From: Hideki Yamane <henrich@debian.org>
Date: Thu, 18 Jun 2015 06:21:20 +0900
Subject: [PATCH] Bug#788964: net-snmp snmp_pdu_parse() DoS
taken patch from https://sourceforge.net/p/net-snmp/code/ci/f23bcd3ac6ddee5d0a48f9703007ccc738914791/
---
snmplib/snmp_api.c | 55 +++++++++++++++++++++++++++---------------------------
1 file changed, 28 insertions(+), 27 deletions(-)
diff --git a/snmplib/snmp_api.c b/snmplib/snmp_api.c
index 191debf09a3d..adae4e4a9550 100644
--- a/snmplib/snmp_api.c
+++ b/snmplib/snmp_api.c
@@ -4350,10 +4350,9 @@ snmp_pdu_parse(netsnmp_pdu *pdu, u_char * data, size_t * length)
u_char type;
u_char msg_type;
u_char *var_val;
- int badtype = 0;
size_t len;
size_t four;
- netsnmp_variable_list *vp = NULL;
+ netsnmp_variable_list *vp = NULL, *vplast = NULL;
oid objid[MAX_OID_LEN];
u_char *p;
@@ -4493,38 +4492,24 @@ snmp_pdu_parse(netsnmp_pdu *pdu, u_char * data, size_t * length)
(ASN_SEQUENCE | ASN_CONSTRUCTOR),
"varbinds");
if (data == NULL)
- return -1;
+ goto fail;
/*
* get each varBind sequence
*/
while ((int) *length > 0) {
- netsnmp_variable_list *vptemp;
- vptemp = (netsnmp_variable_list *) malloc(sizeof(*vptemp));
- if (NULL == vptemp) {
- return -1;
- }
- if (NULL == vp) {
- pdu->variables = vptemp;
- } else {
- vp->next_variable = vptemp;
- }
- vp = vptemp;
+ vp = SNMP_MALLOC_TYPEDEF(netsnmp_variable_list);
+ if (NULL == vp)
+ goto fail;
- vp->next_variable = NULL;
- vp->val.string = NULL;
vp->name_length = MAX_OID_LEN;
- vp->name = NULL;
- vp->index = 0;
- vp->data = NULL;
- vp->dataFreeHook = NULL;
DEBUGDUMPSECTION("recv", "VarBind");
data = snmp_parse_var_op(data, objid, &vp->name_length, &vp->type,
&vp->val_len, &var_val, length);
if (data == NULL)
- return -1;
+ goto fail;
if (snmp_set_var_objid(vp, objid, vp->name_length))
- return -1;
+ goto fail;
len = MAX_PACKET_LENGTH;
DEBUGDUMPHEADER("recv", "Value");
@@ -4604,7 +4589,7 @@ snmp_pdu_parse(netsnmp_pdu *pdu, u_char * data, size_t * length)
vp->val.string = (u_char *) malloc(vp->val_len);
}
if (vp->val.string == NULL) {
- return -1;
+ goto fail;
}
p = asn_parse_string(var_val, &len, &vp->type, vp->val.string,
&vp->val_len);
@@ -4619,7 +4604,7 @@ snmp_pdu_parse(netsnmp_pdu *pdu, u_char * data, size_t * length)
vp->val_len *= sizeof(oid);
vp->val.objid = (oid *) malloc(vp->val_len);
if (vp->val.objid == NULL) {
- return -1;
+ goto fail;
}
memmove(vp->val.objid, objid, vp->val_len);
break;
@@ -4631,7 +4616,7 @@ snmp_pdu_parse(netsnmp_pdu *pdu, u_char * data, size_t * length)
case ASN_BIT_STR:
vp->val.bitstring = (u_char *) malloc(vp->val_len);
if (vp->val.bitstring == NULL) {
- return -1;
+ goto fail;
}
p = asn_parse_bitstring(var_val, &len, &vp->type,
vp->val.bitstring, &vp->val_len);
@@ -4640,12 +4625,28 @@ snmp_pdu_parse(netsnmp_pdu *pdu, u_char * data, size_t * length)
break;
default:
snmp_log(LOG_ERR, "bad type returned (%x)\n", vp->type);
- badtype = -1;
+ goto fail;
break;
}
DEBUGINDENTADD(-4);
+
+ if (NULL == vplast) {
+ pdu->variables = vp;
+ } else {
+ vplast->next_variable = vp;
+ }
+ vplast = vp;
+ vp = NULL;
}
- return badtype;
+ return 0;
+
+ fail:
+ DEBUGMSGTL(("recv", "error while parsing VarBindList\n"));
+ /** if we were parsing a var, remove it from the pdu and free it */
+ if (vp)
+ snmp_free_var(vp);
+
+ return -1;
}
/*
|
