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| author | Thorsten Kukuk <kukuk@thkukuk.de> | 2015-06-22 14:53:01 +0200 |
|---|---|---|
| committer | Thorsten Kukuk <kukuk@thkukuk.de> | 2015-06-22 14:53:01 +0200 |
| commit | e89d4c97385ff8180e6e81e84c5aa745daf28a79 (patch) | |
| tree | 17ef8bacb38a0f60a7476420ab62627cc8af440c /modules/pam_exec | |
| parent | f4fbbbcc52696d67ebe57ee8214fbbdf4c479dbc (diff) | |
| download | pam-e89d4c97385ff8180e6e81e84c5aa745daf28a79.tar.gz pam-e89d4c97385ff8180e6e81e84c5aa745daf28a79.tar.bz2 pam-e89d4c97385ff8180e6e81e84c5aa745daf28a79.zip | |
Release version 1.2.1
Security fix: CVE-2015-3238
If the process executing pam_sm_authenticate or pam_sm_chauthtok method
of pam_unix is not privileged enough to check the password, e.g.
if selinux is enabled, the _unix_run_helper_binary function is called.
When a long enough password is supplied (16 pages or more, i.e. 65536+
bytes on a system with 4K pages), this helper function hangs
indefinitely, blocked in the write(2) call while writing to a blocking
pipe that has a limited capacity.
With this fix, the verifiable password length will be limited to
PAM_MAX_RESP_SIZE bytes (i.e. 512 bytes) for pam_exec and pam_unix.
* NEWS: Update
* configure.ac: Bump version
* modules/pam_exec/pam_exec.8.xml: document limitation of password length
* modules/pam_exec/pam_exec.c: limit password length to PAM_MAX_RESP_SIZE
* modules/pam_unix/pam_unix.8.xml: document limitation of password length
* modules/pam_unix/pam_unix_passwd.c: limit password length
* modules/pam_unix/passverify.c: Likewise
* modules/pam_unix/passverify.h: Likewise
* modules/pam_unix/support.c: Likewise
Diffstat (limited to 'modules/pam_exec')
| -rw-r--r-- | modules/pam_exec/pam_exec.8.xml | 3 | ||||
| -rw-r--r-- | modules/pam_exec/pam_exec.c | 4 |
2 files changed, 4 insertions, 3 deletions
diff --git a/modules/pam_exec/pam_exec.8.xml b/modules/pam_exec/pam_exec.8.xml index 23793668..d1b00a21 100644 --- a/modules/pam_exec/pam_exec.8.xml +++ b/modules/pam_exec/pam_exec.8.xml @@ -106,7 +106,8 @@ During authentication the calling command can read the password from <citerefentry> <refentrytitle>stdin</refentrytitle><manvolnum>3</manvolnum> - </citerefentry>. + </citerefentry>. Only first <emphasis>PAM_MAX_RESP_SIZE</emphasis> + bytes of a password are provided to the command. </para> </listitem> </varlistentry> diff --git a/modules/pam_exec/pam_exec.c b/modules/pam_exec/pam_exec.c index 5ab96303..17ba6ca2 100644 --- a/modules/pam_exec/pam_exec.c +++ b/modules/pam_exec/pam_exec.c @@ -178,11 +178,11 @@ call_exec (const char *pam_type, pam_handle_t *pamh, } pam_set_item (pamh, PAM_AUTHTOK, resp); - authtok = strdupa (resp); + authtok = strndupa (resp, PAM_MAX_RESP_SIZE); _pam_drop (resp); } else - authtok = void_pass; + authtok = strndupa (void_pass, PAM_MAX_RESP_SIZE); if (pipe(fds) != 0) { |