slock

My build of the suckless screenlocker.
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commit 27d8d248275ca3eb63882202dcc21ecf2f81e72a
parent 8a7a68c4c09cbc8b03cb2765ac83e99ca1cc808b
Author: arg@mig29 <unknown>
Date:   Tue, 31 Oct 2006 08:35:54 +0100

applied Vincent's path with some modifications
Diffstat:
Mslock.c | 80++++++++++++++++++++++++++++++++++++++++++-------------------------------------
1 file changed, 43 insertions(+), 37 deletions(-)

diff --git a/slock.c b/slock.c @@ -3,32 +3,55 @@ */ #define _XOPEN_SOURCE 500 -#if HAVE_SHADOW_H -#include <shadow.h> -#else -#include <pwd.h> -#endif - #include <ctype.h> +#include <pwd.h> #include <stdlib.h> #include <stdio.h> #include <string.h> #include <unistd.h> +#if HAVE_SHADOW_H +#include <shadow.h> +#endif #include <sys/types.h> #include <X11/keysym.h> #include <X11/Xlib.h> #include <X11/Xutil.h> +const char * +get_password() { /* only run as root */ + const char *rval; + struct passwd *pw; + + if(geteuid() != 0) { + fputs("slock: cannot retrieve password entry (make sure to suid slock)\n", stderr); + exit(EXIT_FAILURE); + } + pw = getpwuid(getuid()); + endpwent(); + rval = pw->pw_passwd; + +#if HAVE_SHADOW_H + { + struct spwd *sp; + sp = getspnam(getenv("USER")); + endspent(); + rval = sp->sp_pwdp; + } +#endif + /* drop privileges */ + if(setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0) { + fputs("slock: cannot drop privileges\n",stdout); + exit(EXIT_FAILURE); + } + return rval; +} + int main(int argc, char **argv) { char curs[] = {0, 0, 0, 0, 0, 0, 0, 0}; char buf[32], passwd[256]; int num, screen; -#if HAVE_SHADOW_H - struct spwd *sp; -#else - struct passwd *pw; -#endif + const char *pws; unsigned int len; Bool running = True; Cursor invisible; @@ -44,17 +67,7 @@ main(int argc, char **argv) { fputs("slock-"VERSION", (C)opyright MMVI Anselm R. Garbe\n", stdout); exit(EXIT_SUCCESS); } - if(geteuid() != 0) { - fputs("slock: cannot retrieve password entry (make sure to suid slock)\n", stderr); - exit(EXIT_FAILURE); - } -#if HAVE_SHADOW_H - sp = getspnam(getenv("USER")); - endspent(); -#else - pw = getpwuid(getuid()); - endpwent(); -#endif + pws = get_password(); if(!(dpy = XOpenDisplay(0))) { fputs("slock: cannot open display\n", stderr); exit(EXIT_FAILURE); @@ -62,7 +75,7 @@ main(int argc, char **argv) { screen = DefaultScreen(dpy); /* init */ - passwd[0] = 0; + len = 0; wa.override_redirect = 1; wa.background_pixel = BlackPixel(dpy, screen); @@ -89,7 +102,6 @@ main(int argc, char **argv) { /* main event loop */ while(running && !XNextEvent(dpy, &ev)) if(ev.type == KeyPress) { - len = strlen(passwd); buf[0] = 0; num = XLookupString(&ev.xkey, buf, sizeof(buf), &ksym, 0); if(IsFunctionKey(ksym) || IsKeypadKey(ksym) @@ -98,28 +110,22 @@ main(int argc, char **argv) { continue; switch(ksym) { case XK_Return: -#if HAVE_SHADOW_H - if((running = strncmp(crypt(passwd, sp->sp_pwdp), sp->sp_pwdp, sizeof(passwd)))) -#else - if((running = strncmp(crypt(passwd, pw->pw_passwd), pw->pw_passwd, sizeof(passwd)))) -#endif + passwd[len] = 0; + if((running = strcmp(crypt(passwd, pws), pws)) != 0) XBell(dpy, 100); - passwd[0] = 0; + len = 0; break; case XK_Escape: - passwd[0] = 0; + len = 0; break; case XK_BackSpace: if(len) - passwd[--len] = 0; + --len; break; default: if(num && !iscntrl((int) buf[0])) { - buf[num] = 0; - if(len) - strncat(passwd, buf, sizeof(passwd)); - else - strncpy(passwd, buf, sizeof(passwd)); + memcpy(passwd + len,buf,num); + len += num; } break; }