News from AIX

[Gert Doering]

Hi,

News from the "AIX is different than the rest of the world" department...

AIX has something similar to setluid() on SCO, just that it uses text
strings (similar to setenv()) and calls it "usrinfo".  I've appended
the man page below.

Under normal conditions, well-behaved applications use ttyname(),
logname() and getuid() get the relevant informations, but today I've 
come across one piece of commercial software that insists on using
usrinfo(), and otherwise failed to use the proper user name when
being called in an ssh session.  So I'm afraid we have to support that.

To my knowledge, usrinfo() is valid on all AIX systems ever shipped.

Patch is also appended - with that, reading usrinfo() in an ssh session
shows the same value as in a telnet session, so that should be "fine".

gert
-------
Index: session.c
===================================================================
RCS file: /cvs/openssh_cvs/session.c,v
retrieving revision 1.79
diff -u -r1.79 session.c
--- session.c	2001/02/18 19:13:34	1.79
+++ session.c	2001/03/15 15:13:44
@@ -89,6 +89,10 @@
 # define S_UNOFILE_HARD	S_UNOFILE "_hard"
 #endif
 
+#ifdef _AIX
+# include <uinfo.h>
+#endif
+
 /* types */
 
 #define TTYSZ 64
@@ -1119,6 +1123,25 @@
 					debug("error setting satid: %.100s", strerror(errno));
 			}
 #endif /* WITH_IRIX_AUDIT */
+
+#ifdef _AIX
+			/* AIX has a "usrinfo" area where logname and
+			 * other stuff is stored - a few applications
+			 * actually use this and die if it's not set
+			 */
+			{
+			    char ui_buf[1000];
+			    int ui_len;
+
+			    ui_len = sprintf( ui_buf,
+					"LOGNAME=%s%cNAME=%s%cTTY=%s%c%c",
+					pw->pw_name, 0,
+					pw->pw_name, 0,
+					ttyname, 0,0);
+			    usrinfo( SETUINFO, ui_buf, ui_len );
+			    debug("AIX/UsrInfo: set len %d", ui_len);
+			}
+#endif
 
 			/* Permanently switch to the desired uid. */
 			permanently_set_uid(pw->pw_uid);

--------- snip ---------
usrinfo	Subroutine



Purpose

Gets and sets user information about the owner of the current process.

Library

Standard C Library (libc.a)

Syntax

#include <uinfo.h>

int usrinfo (Command, Buffer, Count)
int Command;
char *Buffer;
int Count;

Description

The usrinfo subroutine gets and	sets information about the owner of
the current process. The information is	a sequence of null-terminated
name=value strings. The	last string in the sequence is terminated
by two successive null characters. A child process inherits the	user
information of the parent process.

Parameters

Command	Specifies one of the following constants:

GETUINFO	Copies user information, up to the number of bytes specified
by the Count parameter,	into the buffer	pointed	to by the Buffer parameter.

SETUINFO	Sets the user information for the process to the number	of
bytes specified	by the Count parameter in the buffer pointed to	by
the Buffer parameter. The calling process must have root user authority
to set the user	information.

The minimum user information consists of four strings typically	set
by the login program:

NAME=UserName

LOGIN=LoginName

LOGNAME=LoginName

TTY=TTYName

If the process has no terminal,	the TTYName parameter should be	null.

Buffer	Specifies a pointer to a user buffer. This buffer is usually
UINFOSIZ bytes long.

Count	Specifies the number of	bytes of user information copied from
or to the user buffer.

Return Values

If successful, the usrinfo subroutine returns a	non-negative integer
giving the number of bytes transferred.	Otherwise, a value of -1 is
returned and the errno global variable is set to indicate the error.

Error Codes

The usrinfo subroutine fails if	one of the following is	true:

EPERM	The Command parameter is set to	SETUINFO, and the calling process
does not have root user	authority.

EINVAL	The Command parameter is not set to SETUINFO or	GETUINFO.

EINVAL	The Command parameter is set to	SETUINFO, and the Count	parameter
is larger than UINFOSIZ.

EFAULT	The Buffer parameter points outside of the address space of
the process.

Implementation Specifics

This subroutine	is part	of Base	Operating System (BOS) Runtime.

Related	Information

The getuinfo subroutine, setpenv subroutine.

The login command.

List of	Security and Auditing Subroutines in AIX Version 4 General
Programming Concepts: Writing and Debugging Programs.

Subroutines Overview in	AIX Version 4 General Programming Concepts:
Writing	and Debugging Programs.




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                                                           //www.muc.de/~gert/
Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert.doering at physik.tu-muenchen.de