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Re: PATCH
From: |
Mathias Herberts |
Subject: |
Re: PATCH |
Date: |
Thu, 23 Oct 2003 20:54:44 +0000 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20021130 |
Ok, here it is then.
My patch modifies src/server.c:check_repository_password so it can check
a user password using an external authentication process. I basically
wrote that so I could authenticate my CVS users against our corporate
Active Directory.
The patch relies on a special syntax of the password field in
CVSROOT/passwd. If the password starts with an at sign '@' then
everything following the '@' up to the ':' is considered a path to an
authentication program. As the salt used by crypt(3) cannot contain '@'
we can still use regular encrypted passwords.
If the password field is a path to an authentication program AND there
is a sysuser field on the line then we call the program with three
parameters: repository username password. If the exit status of the
program is 0 the authentication is considered successful, otherwise it
is considered to have failed. The sysuser field is mandatory for my
patch because the users authenticated this way have a high probability
of not existing as system accounts on the server machine (at least it
was the case for my use of AD).
There is a security issue related to the cleartext password being fed as
a parameter to the authentication program, and thus possibly appearing
on a process listing. This is something that was bareable for my set up.
The call to the authentication program is done via system(3) with stdout
and stderr being redirected to /dev/null, whether or not this would work
on a Windows server is something I do not know.
The patch included is against 1.11.6, it applies verbatim to 1.11.9 with
a two lines offset.
Please provide any feedback you think is necessary.
Thanks for your job on CVS.
Regards,
Mathias.
Larry Jones wrote:
Mathias Herberts writes:
I created a patch for CVS to allow for external authentication, I do not
know where to send my patch. Could you please provide me with a pointer
to the right place to submit it.
Right here: bug-cvs@gnu.org.
-Larry Jones
Sheesh. Who can fathom the feminine mind? -- Calvin
--- src/server.c.orig Thu May 1 22:38:16 2003
+++ src/server.c Thu Oct 23 17:20:25 2003
@@ -5265,6 +5265,7 @@
check_repository_password (username, password, repository, host_user_ptr)
char *username, *password, *repository, **host_user_ptr;
{
+ int extauth = 0;
int retval = 0;
FILE *fp;
char *filename;
@@ -5370,12 +5371,70 @@
host_user_tmp = strtok (NULL, ":");
}
+ /*
+ * We have an existing system user portion, check the
+ * password field to see if it is a reference to an
+ * external authentication program, such references are
+ * of the form: @/PATH/TO/AUTH/PROGRAM
+ */
+
+ if (host_user_tmp != NULL && found_password != NULL)
+ {
+ if (found_password[0] == '@')
+ {
+ int res;
+ int len;
+ char * cmdbuf;
+
+ /*
+ * The password field is a reference to an external
+ * authentication program, call it with arguments
+ *
+ * repository username password
+ */
+
+ /*
+ * Allocate memory for cmdbuf, size is that
+ * of found_password - 1 (for the program path),
+ * + repository
+ * + username
+ * + password
+ * + 3 white spaces
+ * + terminating null.
+ */
+
+ len = strlen (found_password)
+ + strlen (repository)
+ + strlen (username)
+ + strlen (password)
+ + strlen (">/dev/null 2>&1")
+ + 4; /* white spaces */
+
+ cmdbuf = (char *) malloc (len);
+
+ if (cmdbuf != (char *) NULL)
+ {
+ snprintf (cmdbuf, len, "%s %s %s %s >/dev/null 2>&1",
found_password + 1, repository, username, password);
+
+ res = system (cmdbuf);
+
+ if (res == 0)
+ {
+ extauth = 1;
+ }
+
+ free (cmdbuf);
+ }
+ }
+ }
+
/* Of course, maybe there was no system user portion... */
if (host_user_tmp == NULL)
host_user_tmp = username;
/* Verify blank passwords directly, otherwise use crypt(). */
- if ((found_password == NULL)
+ if ((extauth == 1)
+ || (found_password == NULL)
|| ((strcmp (found_password, crypt (password, found_password))
== 0)))
{
- PATCH, Mathias Herberts, 2003/10/23
- Re: PATCH, Larry Jones, 2003/10/23
- Re: PATCH,
Mathias Herberts <=