- Chris Hardie <[EMAIL PROTECTED]>:
| Is there any state information stored by qmail in terms of usernames
| and domains?
No surprises of that kind in qmail. qmail-local looks for and reads
.qmail over again on each delivery. In fact, a separate copy of
qmail-local is run each time.
But wait! I have an idea! It just occured to me that "lindgren" is
exactly 8 characters long, which is exactly the maximum length of a
username on many systems. So here is my conjecture: When your
system's getpwnam() is fed anything longer than 8 characters, it chops
it down to 8 characters and looks up the remainder in the database.
In fact, looking at the code in qmail-getpw.c, this is the only
reasonable explanation I can come up with (for some unreasonable
definition of "reasonable").
To help verify my hypothesis, try compiling and running the appended
program. Running it as ./getpwnam lindgren-pat will then return
lindgren-pat: name="lindgren", uid=1021, gid=1021, homedir=/home/lindgren
Here is a sample run on my system:
; gcc -o getpwnam getpwnam.c
; ./getpwnam hanche operator operator-foo
hanche: name="hanche", uid=1357, gid=1999, homedir=/home/fiinbeck/hanche
operator: name="operator", uid=5, gid=5, homedir=/home-pw/operator
operator-foo: nope.
So what system is this happening on? I am sure Dan will be
interested, so he can try to harden qmail against this kind of
silliness.
- Harald
#include <sys/types.h>
#include <pwd.h>
#include <stdio.h>
int main(int argc, char *argv[]) {
struct passwd *pw;
while (*(++argv)) {
printf ("%s: ", *argv);
pw = getpwnam(*argv);
if (pw)
printf("name=\"%s\", uid=%d, gid=%d, homedir=%s\n",
pw->pw_name, pw->pw_uid, pw->pw_gid, pw->pw_dir);
else
printf("nope.\n");
}
}
