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From 961e835bda6caebf70ee3835b2c166aeab10a258 Mon Sep 17 00:00:00 2001
From: Olivier Brunel <jjk@jjacky.com>
Date: Sat, 9 Jan 2016 17:47:57 +0100
Subject: [PATCH 11/11] Handle perms on tty node
Upon login we take note of current user/group/perms, to restore it on session
close. Then, we set the user owner, and TTY_GROUP ("tty") as group. If the
group doesn't exist we chmod 0600, else 0620.
Signed-off-by: Olivier Brunel <jjk@jjacky.com>
---
include/config.h | 2 ++
include/xlsh.h | 4 +--
src/xlsh.c | 74 +++++++++++++++++++++++++++++++++++++++++++-------------
3 files changed, 61 insertions(+), 19 deletions(-)
diff --git a/include/config.h b/include/config.h
index 1844bd3..89aabc7 100644
--- a/include/config.h
+++ b/include/config.h
@@ -23,6 +23,8 @@
#define XLSH_TIMEFMT "%H:%M"
#define XLSH_PAM_TTY "login"
+#define TTY_GROUP "tty"
+
#define XLSH_COMPLETION_LOGIN 0
#define XLSH_COMPLETION_SHOWROOT 1
#define XLSH_COMPLETION_MINUID 1000
diff --git a/include/xlsh.h b/include/xlsh.h
index 0a131db..9108db9 100644
--- a/include/xlsh.h
+++ b/include/xlsh.h
@@ -38,10 +38,10 @@ typedef struct xlsh_system_s {
struct utsname un;
char date[100];
char time[100];
- char ttyname[256];
- char ttypath[256];
char hostname[256];
char domainname[256];
+ char *ttyname;
+ char *ttypath;
} xlsh_system_t;
void xlsh_config_init(char* exec_arg);
diff --git a/src/xlsh.c b/src/xlsh.c
index 7a3ceb9..b97897c 100644
--- a/src/xlsh.c
+++ b/src/xlsh.c
@@ -18,6 +18,7 @@
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/utsname.h>
+#include <sys/stat.h>
#include <readline/readline.h>
#include <readline/history.h>
@@ -27,6 +28,8 @@
#include <libxlsh.h>
#include <xlsh.h>
+static char tty_name[PATH_MAX];
+
// Static data
static xlsh_config_item_t xlsh_config[] = {
{ "XLSH_EXEC", XLSH_EXEC, NULL },
@@ -237,7 +240,7 @@ int xlsh_session_open(const char* service, const char* user,
if(pam_start(service, user, &conv, &pam_handle) != PAM_SUCCESS)
return XLSH_ERROR;
- pam_set_item(pam_handle, PAM_TTY, ttyname(0));
+ pam_set_item(pam_handle, PAM_TTY, tty_name);
if(pam_authenticate(pam_handle, 0) != PAM_SUCCESS) {
pam_end(pam_handle, 0);
@@ -341,8 +344,13 @@ int xlsh_session_exec(pam_handle_t* handle, const char* session, const char* arg
int xlsh_session_tty(const char* user, const char* shell)
{
+ int r = XLSH_EDONE;
pam_handle_t* pam_handle;
struct passwd* pwinfo;
+ struct group* gr;
+ struct stat st;
+ gid_t gid;
+ mode_t mode;
int waitflag;
char user_shell[PATH_MAX];
@@ -368,18 +376,52 @@ int xlsh_session_tty(const char* user, const char* shell)
return XLSH_ERROR;
}
+ if(stat(tty_name, &st) < 0) {
+ st.st_uid = 0;
+ st.st_gid = 0;
+ st.st_mode = S_IRUSR | S_IWUSR;
+ }
+
+ gr = getgrnam(TTY_GROUP);
+ if(gr) {
+ gid = gr->gr_gid;
+ mode = S_IRUSR | S_IWUSR | S_IWGRP;
+ } else {
+ gid = pwinfo->pw_gid;
+ mode = S_IRUSR | S_IWUSR;
+ }
+
+ if(chown(tty_name, pwinfo->pw_uid, gid) < 0) {
+ fprintf(stderr, "Unable to chown '%s': %s\n", tty_name, strerror(errno));
+ xlsh_session_close(pam_handle);
+ return XLSH_ERROR;
+ }
+ if(chmod(tty_name, mode) < 0) {
+ fprintf(stderr, "Unable to chmod '%s': %s\n", tty_name, strerror(errno));
+ r = XLSH_ERROR;
+ goto done;
+ }
+
sprintf(user_shell_name, "-%s", user_shell);
if(xlsh_session_exec(pam_handle, user_shell, user_shell_name) != XLSH_EOK) {
fprintf(stderr, "Cannot execute shell process: %s\n", user_shell);
- xlsh_session_close(pam_handle);
- return XLSH_ERROR;
+ r = XLSH_ERROR;
+ goto done;
}
waitflag = 0;
wait(&waitflag);
-
+
+done:
+ if(chown(tty_name, st.st_uid, st.st_gid) < 0)
+ fprintf(stderr, "Warning: Failed to restore chown '%s': %s\n",
+ tty_name, strerror(errno));
+ if(chmod(tty_name, st.st_mode) < 0)
+ fprintf(stderr, "Warning: Failed to restore chmod '%s': %s\n",
+ tty_name, strerror(errno));
+
xlsh_session_close(pam_handle);
- return XLSH_EDONE;
+ return r;
}
@@ -552,23 +594,16 @@ int xlsh_sys_getinfo(xlsh_system_t* sysinfo)
{
struct tm *tminfo;
time_t timeval;
-
- char *tty_name;
- char tty_path[PATH_MAX];
-
+
memset(sysinfo, 0, sizeof(xlsh_system_t));
uname(&sysinfo->un);
if(gethostname(sysinfo->hostname, sizeof(sysinfo->hostname)) != 0)
strcpy(sysinfo->hostname, "localhost");
if(getdomainname(sysinfo->domainname, sizeof(sysinfo->domainname)) != 0)
strcpy(sysinfo->domainname, "localdomain");
- if(ttyname_r(0, tty_path, sizeof(tty_path)) != 0)
- strcpy(tty_path, XLSH_XTTY);
- strncpy(sysinfo->ttypath, tty_path + 5, sizeof(sysinfo->ttypath));
-
- tty_name = tty_path + 5;
- strncpy(sysinfo->ttyname, tty_name, sizeof(sysinfo->ttyname));
-
+ sysinfo->ttypath = tty_name;
+ sysinfo->ttyname = tty_name + 5;
+
timeval = time(NULL);
tminfo = localtime(&timeval);
if(tminfo) {
@@ -614,7 +649,7 @@ int xlsh_sys_issue(const char* issuefile)
case 'v': value = sysinfo.un.version; break;
case 't': value = sysinfo.time; break;
case 'd': value = sysinfo.date; break;
- case 'l': value = sysinfo.ttypath; break;
+ case 'l': value = sysinfo.ttyname; break;
case 'n': value = sysinfo.hostname; break;
case 'o': value = sysinfo.domainname; break;
default: value = NULL;
@@ -649,6 +684,11 @@ int main(int argc, char** argv)
return EXIT_FAILURE;
}
+ if(ttyname_r(fileno(stdin), tty_name, sizeof(tty_name)) != 0) {
+ fprintf(stderr, "%s: Unable to get tty name\n", argv[0]);
+ return EXIT_FAILURE;
+ }
+
xlsh_config_init(opt_exec);
xlsh_sys_issue(xlsh_config[XLSH_ID_ISSUE].value);
--
2.7.0
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