Re: (ITS#9124) Unauthenticated remote denial-of-service (Null pointer dereference in ber_skip_tag) - openldap-bugs

29 Nov 2019

--------------ms020107020804030202050609
Content-Type: multipart/mixed;
 boundary="------------B39567B16EE4CE18797C4253"
Content-Language: en-US
This is a multi-part message in MIME format.
--------------B39567B16EE4CE18797C4253
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Hi Ond=C5=99ej =E2=80=94
The commit 1dbf0e9441def3d6dbc0fa8fba3c2e86fa50fa19 seems to fix the null=
 pointer dereference issue.
Using honggfuzz netdriver module, fuzzing of slapd can be accomplished re=
latively easy. You can follow the below instructions to fuzz the server:
1. Install honggfuzz (stable)
$ export CC=3Dhfuzz-clang
$ export CXX=3Dhfuzz-clang++
2. Apply attached patch (fuzz.patch)
3. Compile openldap
$ ./configure
$ make depend
$ make
$ make install
4. Create testcase directory including seeds (probably you have way bette=
r seeds then I have :), I just used ldap payloads extracted from some pca=
p's)
$ mkdir testcases
5. Start fuzzing
$ HFND_TCP_PORT=3D9090 honggfuzz -w ldap.wordlist -f testcases/ -- ./libe=
xec/slapd -d 1 -h ldap://127.0.0.1:9090
As you see, the fuzzing setup is relatively simple thanks to honggfuzz.
Hope this helps!
Note: After Cyrus SASL fixes the other issue #9123, I will request CVE id=
's for the two bugs and share them as a reference in the relevant issues =
(#9123, #9124)
Cheers
=C2=A0=C2=A0=C2=A0 -Stephan
On 11/29/19 1:06 PM, Ond=C5=99ej Kuzn=C3=ADk wrote:
...
On Fri, Nov 29, 2019 at 09:08:15AM +0000, stephan@srlabs.de wrote:
...
Unauthenticated remote denial-of-service through malformed ldap packet=
...
...
caused by a null pointer dereference in ber_skip_tag function
(libraries/liblber/decode.c).
=3D=3D4066091=3D=3D    by 0x4FD051: cancel_extop (cancel.c:52)
Hi Stephan,
thanks for the report, this should be fixed by commit
1dbf0e9441def3d6dbc0fa8fba3c2e86fa50fa19 in master.
Looks like you are fuzzing the server which has been on my to do list
for a while, many thanks for that and I'm looking forward to reading
how you did it. Would you be willing to help the project integrate your=
...
work in its testing process after you've finished?
Thanks,
--------------B39567B16EE4CE18797C4253
Content-Type: text/x-patch; charset=UTF-8;
 name="fuzz.patch"
Content-Transfer-Encoding: quoted-printable
Content-Disposition: attachment;
 filename="fuzz.patch"

diff --git a/servers/slapd/main.c b/servers/slapd/main.c
index f528aa951..1941ae3de 100644
--- a/servers/slapd/main.c
+++ b/servers/slapd/main.c
@@ -349,12 +349,14 @@ usage( char *name )
     );
 }
=20
-#ifdef HAVE_NT_SERVICE_MANAGER
-void WINAPI ServiceMain( DWORD argc, LPTSTR *argv )
+//#ifdef HAVE_NT_SERVICE_MANAGER
+//void WINAPI ServiceMain( DWORD argc, LPTSTR *argv )
+//#else
+#ifdef HFND_FUZZING_ENTRY_FUNCTION
+HFND_FUZZING_ENTRY_FUNCTION(int argc, char **argv) {
 #else
-int main( int argc, char **argv )
+int main( int argc, char **argv ) {
 #endif
-{
    int		i, no_detach =3D 0;
    int		rc =3D 1;
    char *urls =3D NULL;
--------------B39567B16EE4CE18797C4253--
--------------ms020107020804030202050609
Content-Type: application/pkcs7-signature; name="smime.p7s"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="smime.p7s"
Content-Description: S/MIME Cryptographic Signature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--------------ms020107020804030202050609--

    