Package: libpam-yubico
Version: 2.10-1
Severity: important
Tags: upstream patch
I use a Yubikey 2.2.4 with libpam-yubico for challenge-response authentication.
The authentication requires two phases of challenges-responses. I set the
Yubikey to wait for key press before answering the challenges. Sometimes when I
press the key too long at the first phase, it segfaults like this instead of a
simple failure:
*** glibc detected *** sudo: double free or corruption (out):
0x000000000138efc0 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x72656)[0x7fc05233f656]
/lib/x86_64-linux-gnu/libc.so.6(cfree+0x6c)[0x7fc05234438c]
/lib/x86_64-linux-gnu/libc.so.6(fclose+0x14d)[0x7fc0523305ad]
/lib/security/pam_yubico.so(pam_sm_authenticate+0xb1e)[0x7fc050fdfb0e]
/lib/x86_64-linux-gnu/libpam.so.0(+0x31f5)[0x7fc0511e71f5]
/lib/x86_64-linux-gnu/libpam.so.0(pam_authenticate+0x38)[0x7fc0511e6a78]
/usr/lib/sudo/sudoers.so(+0x6442)[0x7fc0513f8442]
/usr/lib/sudo/sudoers.so(+0x5d34)[0x7fc0513f7d34]
...
The following working patch clearly shows the problem.
diff -ru5p yubico-pam-2.10.orig/pam_yubico.c yubico-pam-2.10/pam_yubico.c
--- yubico-pam-2.10.orig/pam_yubico.c 2011-12-13 23:54:55.000000000 +0800
+++ yubico-pam-2.10/pam_yubico.c 2012-01-27 01:36:41.139640251 +0800
@@ -524,10 +524,11 @@ do_challenge_response(pam_handle_t *pamh
if (fclose(f) < 0) {
f = NULL;
goto out;
}
+ f = NULL;
if (restore_privileges(pamh) < 0) {
DBG (("could not restore privileges"));
goto out;
}
...
out:
...
if (f)
fclose(f);
-- System Information:
Debian Release: wheezy/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Kernel: Linux 3.2.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages libpam-yubico depends on:
ii debconf [debconf-2.0] 1.5.41
ii libc6 2.13-24
ii libldap-2.4-2 2.4.28-1.1
ii libpam-runtime 1.1.3-6
ii libpam0g 1.1.3-6
ii libykclient3 2.6-1
ii libykpers-1-1 1.6.3-1
ii libyubikey0 1.7-1
libpam-yubico recommends no packages.
libpam-yubico suggests no packages.
-- debconf information excluded
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