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Diffstat (limited to 'libpam/pam_modutil_getlogin.c')
-rw-r--r--libpam/pam_modutil_getlogin.c80
1 files changed, 80 insertions, 0 deletions
diff --git a/libpam/pam_modutil_getlogin.c b/libpam/pam_modutil_getlogin.c
new file mode 100644
index 0000000..04a20fd
--- /dev/null
+++ b/libpam/pam_modutil_getlogin.c
@@ -0,0 +1,80 @@
+/*
+ * $Id$
+ *
+ * A central point for invoking getlogin(). Hopefully, this is a
+ * little harder to spoof than all the other versions that are out
+ * there.
+ */
+
+#include "pam_modutil_private.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <utmp.h>
+
+#define _PAMMODUTIL_GETLOGIN "_pammodutil_getlogin"
+
+const char *
+pam_modutil_getlogin(pam_handle_t *pamh)
+{
+ int status;
+ const void *logname;
+ const void *void_curr_tty;
+ const char *curr_tty;
+ char *curr_user;
+ struct utmp *ut, line;
+
+ status = pam_get_data(pamh, _PAMMODUTIL_GETLOGIN, &logname);
+ if (status == PAM_SUCCESS) {
+ return logname;
+ }
+
+ status = pam_get_item(pamh, PAM_TTY, &void_curr_tty);
+ if ((status != PAM_SUCCESS) || (void_curr_tty == NULL))
+ curr_tty = ttyname(0);
+ else
+ curr_tty = (const char*)void_curr_tty;
+
+ if (curr_tty == NULL) {
+ return NULL;
+ }
+
+ if (curr_tty[0] == '/') { /* full path */
+ const char *t;
+ curr_tty++;
+ if ((t = strchr(curr_tty, '/')) != NULL) {
+ curr_tty = t + 1;
+ }
+ }
+ logname = NULL;
+
+ setutent();
+ strncpy(line.ut_line, curr_tty, sizeof(line.ut_line));
+
+ if ((ut = getutline(&line)) == NULL) {
+ goto clean_up_and_go_home;
+ }
+
+ curr_user = calloc(sizeof(line.ut_user)+1, 1);
+ if (curr_user == NULL) {
+ goto clean_up_and_go_home;
+ }
+
+ strncpy(curr_user, ut->ut_user, sizeof(ut->ut_user));
+ /* calloc already zeroed the memory */
+
+ status = pam_set_data(pamh, _PAMMODUTIL_GETLOGIN, curr_user,
+ pam_modutil_cleanup);
+ if (status != PAM_SUCCESS) {
+ free(curr_user);
+ goto clean_up_and_go_home;
+ }
+
+ logname = curr_user;
+
+clean_up_and_go_home:
+
+ endutent();
+
+ return logname;
+}