ericonr
/
util-linux
mirror of https://github.com/ericonr/util-linux.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

su: (pty) change owner and mode for pty 

The current situation:

 # su --pty - kzak
 $ ll $(tty)
 crw--w---- 1 root tty 136, 9 Feb 23 11:53 /dev/pts/9
 $ mesg
 mesg: cannot open /dev/pts/9: Permission denied

the pseudo-terminal is still owned by the original user.

New version:

 # su --pty - kzak
 # ll $(tty)
 crw--w---- 1 kzak tty 136, 9 Feb 23 11:56 /dev/pts/9
 # mesg
 is y

The patch follows login(1) to change the pty owner and group. It
follows "TTYPERM" and "TTYGROUP" from login.defs (or econf lib).

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2021-02-23 11:52:45 +01:00
parent 726ffb4a26
commit 17d5b26436
3 changed files with 35 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/pty-session.h
View File

@ -10,6 +10,7 @@
#include <termios.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/signalfd.h>
@ -98,6 +99,7 @@ struct ul_pty_callbacks *ul_pty_get_callbacks(struct ul_pty *pty);
int ul_pty_is_running(struct ul_pty *pty);
int ul_pty_setup(struct ul_pty *pty);
void ul_pty_cleanup(struct ul_pty *pty);
int ul_pty_chownmod_slave(struct ul_pty *pty, uid_t uid, gid_t gid, mode_t mode);
void ul_pty_init_slave(struct ul_pty *pty);
int ul_pty_proxy_master(struct ul_pty *pty);

9
lib/pty-session.c
View File

@ -239,6 +239,15 @@ void ul_pty_cleanup(struct ul_pty *pty)
tcsetattr(STDIN_FILENO, TCSADRAIN, &rtt);
}
int ul_pty_chownmod_slave(struct ul_pty *pty, uid_t uid, gid_t gid, mode_t mode)
{
if (fchown(pty->slave, uid, gid))
return -errno;
if (fchmod(pty->slave, mode))
return -errno;
return 0;
}
/* call me in child process */
void ul_pty_init_slave(struct ul_pty *pty)
{

26
login-utils/su-common.c
View File

@ -82,7 +82,6 @@ UL_DEBUG_DEFINE_MASKNAMES(su) = UL_DEBUG_EMPTY_MASKNAMES;
#define DBG(m, x) __UL_DBG(su, SU_DEBUG_, m, x)
#define ON_DBG(m, x) __UL_DBG_CALL(su, SU_DEBUG_, m, x)
/* name of the pam configuration files. separate configs for su and su - */
#define PAM_SRVNAME_SU "su"
#define PAM_SRVNAME_SU_L "su-l"
@ -255,6 +254,26 @@ static void wait_for_child_cb(
{
wait_for_child((struct su_context *) data);
}
static void chownmod_pty(struct su_context *su)
{
gid_t gid = su->pwd->pw_gid;
mode_t mode = (mode_t) getlogindefs_num("TTYPERM", TTY_MODE);
const char *grname = getlogindefs_str("TTYGROUP", TTYGRPNAME);
if (grname && *grname) {
struct group *gr = getgrnam(grname);
if (gr) /* group by name */
gid = gr->gr_gid;
else /* group by ID */
gid = (gid_t) getlogindefs_num("TTYGROUP", gid);
}
if (ul_pty_chownmod_slave(su->pty,
su->pwd->pw_uid,
gid, mode))
warn(_("change owner or mode for pseudo-terminal failed"));
}
#endif
/* Log the fact that someone has run su to the user given by PW;
@ -496,7 +515,6 @@ static void parent_setup_signals(struct su_context *su)
}
}
static void create_watching_parent(struct su_context *su)
{
int status;
@ -1191,6 +1209,10 @@ int su_main(int argc, char **argv, int mode)
create_watching_parent(su);
/* Now we're in the child. */
#ifdef USE_PTY
if (su->force_pty)
chownmod_pty(su);
#endif
change_identity(su->pwd);
if (!su->same_session) {
/* note that on --pty we call setsid() in ul_pty_init_slave() */