Russell Coker
2009-Jun-11 08:42 UTC
[Secure-testing-team] Bug#532740: libdkim0d: Should use strtok_r() not strtok() for thread safety
Package: libdkim0d
Version: 1:1.0.19-3
Severity: grave
Tags: security
Justification: user security hole
The following patch makes libdkim use strtok_r() instead of strtok() for thread
safety.
If a server process has multiple threads operating on behalf of different users
while verifying dkim data (IE receiving mail for multiple users) then data may
be leaked. Also this may cause a server process to crash and there is a
possibility of it being an exploitable bug.
I don''t think that the security concerns are great enough to make a
secret
report for a coordinated release, but I do think that they are great enough
to justify a grave bug report.
diff -ru libdkim-1.0.19/src/dkimverify.cpp libdkim-1.0.19-new/src/dkimverify.cpp
--- libdkim-1.0.19/src/dkimverify.cpp 2008-05-12 20:08:06.000000000 +1000
+++ libdkim-1.0.19-new/src/dkimverify.cpp 2009-06-11 18:28:10.000000000 +1000
@@ -855,6 +855,9 @@
////////////////////////////////////////////////////////////////////////////////
int CDKIMVerify::ParseDKIMSignature( const string& sHeader, SignatureInfo
&sig )
{
+ // for strtok_r()
+ char *saveptr;
+
// save header for later
sig.Header = sHeader;
@@ -1032,7 +1035,7 @@
{
// make sure "dns" is in the list
bool HasDNS = false;
- char *s = strtok(values[9], ":");
+ char *s = strtok_r(values[9], ":", &saveptr);
while (s != NULL)
{
if (strncmp(s, "dns", 3) == 0 && (s[3] ==
''\0'' || s[3] == ''/''))
@@ -1040,7 +1043,7 @@
HasDNS = true;
break;
}
- s = strtok(NULL, ": \t");
+ s = strtok_r(NULL, ": \t", &saveptr);
}
if (!HasDNS)
return DKIM_BAD_SYNTAX; // todo: maybe create a new error code for unknown
query method
@@ -1080,7 +1083,7 @@
// parse the signed headers list
bool HasFrom = false, HasSubject = false;
RemoveSWSP(values[4]); // header names shouldn''t have spaces in
them so this should be ok...
- char *s = strtok(values[4], ":");
+ char *s = strtok_r(values[4], ":", &saveptr);
while (s != NULL)
{
if (_stricmp(s, "From") == 0)
@@ -1090,7 +1093,7 @@
sig.SignedHeaders.push_back(s);
- s = strtok(NULL, ":");
+ s = strtok_r(NULL, ":", &saveptr);
}
if (!HasFrom)
@@ -1194,6 +1197,9 @@
////////////////////////////////////////////////////////////////////////////////
int SelectorInfo::Parse( char* Buffer )
{
+ // for strtok_r()
+ char *saveptr;
+
static const char *tags[] =
{"v","g","h","k","p","s","t","n",NULL};
char *values[sizeof(tags)/sizeof(tags[0])] = {NULL};
@@ -1235,14 +1241,14 @@
else
{
// MUST include "sha1" or "sha256"
- char *s = strtok(values[2], ":");
+ char *s = strtok_r(values[2], ":", &saveptr);
while (s != NULL)
{
if (strcmp(s, "sha1") == 0)
AllowSHA1 = true;
else if (strcmp(s, "sha256") == 0)
AllowSHA256 = true;
- s = strtok(NULL, ":");
+ s = strtok_r(NULL, ":", &saveptr);
}
if ( !(AllowSHA1 || AllowSHA256) )
return DKIM_SELECTOR_INVALID; // todo: maybe create a new error code for
unsupported hash algorithm
@@ -1261,7 +1267,7 @@
{
// make sure "*" or "email" is in the list
bool ServiceTypeMatch = false;
- char *s = strtok(values[5], ":");
+ char *s = strtok_r(values[5], ":", &saveptr);
while (s != NULL)
{
if (strcmp(s, "*") == 0 || strcmp(s, "email") == 0)
@@ -1269,7 +1275,7 @@
ServiceTypeMatch = true;
break;
}
- s = strtok(NULL, ":");
+ s = strtok_r(NULL, ":", &saveptr);
}
if (!ServiceTypeMatch)
return DKIM_SELECTOR_INVALID;
@@ -1278,7 +1284,7 @@
// flags
if (values[6] != NULL)
{
- char *s = strtok(values[6], ":");
+ char *s = strtok_r(values[6], ":", &saveptr);
while (s != NULL)
{
if (strcmp(s, "y") == 0)
@@ -1289,7 +1295,7 @@
{
SameDomain = true;
}
- s = strtok(NULL, ":");
+ s = strtok_r(NULL, ":", &saveptr);
}
}
@@ -1388,6 +1394,9 @@
////////////////////////////////////////////////////////////////////////////////
int CDKIMVerify::GetSSP( const string &sDomain, int &iSSP, bool
&bTesting )
{
+ // for strtok_r()
+ char *saveptr;
+
string sFQDN = "_ssp._domainkey.";
sFQDN += sDomain;
@@ -1456,7 +1465,7 @@
// flags
if (values[1] != NULL)
{
- char *s = strtok(values[1], "|");
+ char *s = strtok_r(values[1], "|", &saveptr);
while (s != NULL)
{
if (strcmp(s, "y") == 0)
@@ -1474,7 +1483,7 @@
return DKIM_SUCCESS;
}
}
- s = strtok(NULL, "|");
+ s = strtok_r(NULL, "|", &saveptr);
}
}
}
-- System Information:
Debian Release: 5.0.1
APT prefers stable
APT policy: (500, ''stable'')
Architecture: i386 (i686)
Kernel: Linux 2.6.26-1-686 (SMP w/1 CPU core)
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=ANSI_X3.4-1968)
(ignored: LC_ALL set to C)
Shell: /bin/sh linked to /bin/bash
Versions of packages libdkim0d depends on:
ii libc6 2.7-18 GNU C Library: Shared libraries
ii libgcc1 1:4.3.2-1.1 GCC support library
ii libssl0.9.8 0.9.8g-15+lenny1 SSL shared libraries
ii libstdc++6 4.3.2-1.1 The GNU Standard C++ Library v3
libdkim0d recommends no packages.
libdkim0d suggests no packages.
-- no debconf information