diff options
| -rw-r--r-- | src/cerberus.c | 19 | ||||
| -rw-r--r-- | src/cerberus.h | 1 | ||||
| -rw-r--r-- | src/security.c | 82 | ||||
| -rw-r--r-- | src/security.h | 18 |
4 files changed, 99 insertions, 21 deletions
diff --git a/src/cerberus.c b/src/cerberus.c index d84ea50..ca4cf48 100644 --- a/src/cerberus.c +++ b/src/cerberus.c @@ -33,6 +33,8 @@ int main(int argc, char** argv) char* passphrase = NULL; char preserve_env = 0; char skip_auth = 0; + struct passwd* entry; + /* Disable echoing */ disable_echo(); @@ -100,7 +102,6 @@ int main(int argc, char** argv) if (username == 0) { printf("%s: no username specified\n", *argv); - reenable_echo(); sleep(ERROR_SLEEP); return 2; } @@ -130,6 +131,15 @@ int main(int argc, char** argv) /* Get user information */ + if ((entry = getpwnam(username)) == NULL) + { + if (errno) + perror("getpwnam"); + else + printf("User does not exist\n"); + sleep(ERROR_SLEEP); + return 1; + } /* Get the passphrase, if -f has not been used */ @@ -155,6 +165,13 @@ int main(int argc, char** argv) /* Reset terminal settings */ reenable_echo(); + + /* TODO login */ + + + /* Reset terminal ownership */ + chown_tty(0, 0, 0); + return 0; } diff --git a/src/cerberus.h b/src/cerberus.h index c2ea2af..1dbd029 100644 --- a/src/cerberus.h +++ b/src/cerberus.h @@ -20,6 +20,7 @@ #include <unistd.h> #include <signal.h> #include <pwd.h> +#include <errno.h> #include "passphrase.h" #include "quit.h" 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"); + } + } +} + diff --git a/src/security.h b/src/security.h index 3e12af4..bbc0c4e 100644 --- a/src/security.h +++ b/src/security.h @@ -24,8 +24,26 @@ #include <signal.h> +#ifndef TTY_PERM +#define TTY_PERM 0600 +#endif + +#ifndef FAILURE_SLEEP +#define FAILURE_SLEEP 5 +#endif + + /** * Secure the TTY from spying */ void secure_tty(void); +/** + * 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); + |