weston-launch: check string truncation

Since weston-launch is a setuid-root program we should be extra careful:
Check for a potential string trunction. Move the check in a separate
function and return with error in case trunction has happened.

Signed-off-by: Stefan Agner <stefan@agner.ch>
This commit is contained in:
Stefan Agner 2020-01-22 22:23:07 +01:00 committed by Pekka Paalanen
parent c6f818a016
commit 247392a322
1 changed files with 14 additions and 3 deletions

View File

@ -294,6 +294,19 @@ setenv_fd(const char *env, int fd)
setenv(env, buf, 1);
}
static int
open_tty_by_number(int ttynr)
{
int ret;
char filename[16];
ret = snprintf(filename, sizeof filename, "/dev/tty%d", ttynr);
if (ret < 0)
return -1;
return open(filename, O_RDWR | O_NOCTTY);
}
static int
send_reply(struct weston_launch *wl, int reply)
{
@ -557,7 +570,6 @@ setup_tty(struct weston_launch *wl, const char *tty)
wl->tty = open(tty, O_RDWR | O_NOCTTY);
} else {
int tty0 = open("/dev/tty0", O_WRONLY | O_CLOEXEC);
char filename[16];
if (tty0 < 0) {
fprintf(stderr, "weston: could not open tty0: %s\n",
@ -572,8 +584,7 @@ setup_tty(struct weston_launch *wl, const char *tty)
return -1;
}
snprintf(filename, sizeof filename, "/dev/tty%d", wl->ttynr);
wl->tty = open(filename, O_RDWR | O_NOCTTY);
wl->tty = open_tty_by_number(wl->ttynr);
close(tty0);
}