diff options
Diffstat (limited to 'src/security.c')
| -rw-r--r-- | src/security.c | 82 |
1 files changed, 62 insertions, 20 deletions
diff --git a/src/security.c b/src/security.c index 04ec33d..1dc8c8c 100644 --- a/src/security.c +++ b/src/security.c @@ -19,36 +19,26 @@ #include "security.h" -#ifndef TTY_PERM -#define TTY_PERM 0600 -#endif - -#ifndef FAILURE_SLEEP -#define FAILURE_SLEEP 5 -#endif - - -#define fail(FUNC) ({ perror(#FUNC); sleep(FAILURE_SLEEP); _exit(1); }) - +static inline void fail(char* str) +{ + perror(str); + sleep(FAILURE_SLEEP); + _exit(1); +} /** * Secure the TTY from spying */ -void secure_tty(void) /* TODO /dev/vcs[a][0-9]+ */ +void secure_tty(void) { struct termios tty; struct termios saved_tty; char* tty_device; int fd, i; - /* Take owner ship of this TTY */ - if (fchown(STDIN_FILENO, 0, 0)) - fail(fchown); - - /* Restrict others from using this TTY */ - if (fchmod(STDIN_FILENO, TTY_PERM)) - fail(fchmod); + /* Set ownership of this TTY to root:root */ + chown_tty(0, 0, 1); /* Get TTY name for last part of this functions */ tty_device = ttyname(STDIN_FILENO); @@ -68,7 +58,7 @@ void secure_tty(void) /* TODO /dev/vcs[a][0-9]+ */ /* Restore terminal and TTY modes */ fd = open(tty_device, O_RDWR | O_NONBLOCK); if (fd == -1) - fail(open); + fail("open"); fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) & ~O_NONBLOCK); for (i = 0; i < fd; i++) close(i); @@ -80,3 +70,55 @@ void secure_tty(void) /* TODO /dev/vcs[a][0-9]+ */ tcgetattr(STDIN_FILENO, &saved_tty); } + +/** + * Set ownership and mode of the TTY + * + * @param owner The owner + * @param group The group + * @param with_fail Abort on failure + */ +void chown_tty(int owner, int group, int with_fail) +{ + struct vt_stat vtstat; + + /* Set ownership of this TTY */ + if (fchown(STDIN_FILENO, owner, group) && with_fail) + fail("fchown"); + + /* Restrict others from using this TTY */ + if (fchmod(STDIN_FILENO, TTY_PERM) && with_fail) + fail("fchmod"); + + /* Also do the above for /dev/vcs[a][0-9]+ */ + if (ioctl(STDIN_FILENO, VT_GETSTATE, &vtstat) == 0) + { + int n = vtstat.v_active; + char vcs[16]; + char vcsa[16]; + + vcs += 16; + vcsa += 16; + + if (n) + { + *--vcs = *--vcsa = 0; + while (n) + { + *--vcs = *--vcsa = (n % 10) + '0'; + n /= 10; + } + + vcs -= 8; + vcsa -= 9; + strcpy(vcs, "/dev/vcs"); + strcpy(vcsa, "/dev/vcsa"); + + if (fchown(vcs, owner, group) && with_fail) fail("chown"); + if (fchown(vcsa, owner, group) && with_fail) fail("chown"); + if (fchmod(vcs, TTY_PERM) && with_fail) fail("chmod"); + if (fchmod(vcsa, TTY_PERM) && with_fail) fail("chmod"); + } + } +} + |