alema/us
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

more comment and bug fix

Browse Source 
commented some stuff and fixed config parser ignoring invalid config keywords
This commit is contained in:
Alessandro Mauri 2021-07-14 10:00:07 +02:00
parent 86a6af5073
commit 391353cea6
1 changed files with 25 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
us.c
View File

@ -279,10 +279,12 @@ int main(int argc, char *argv[])
{NULL, NULL} {NULL, NULL}
}; };
if (envflag) { /* clear env */ /* Copy what has to be copied and then clear the environment, we'll
* make a fresh one later */
if (envflag) {
for (int i = 0; env_keep[i].name; i++) for (int i = 0; env_keep[i].name; i++)
env_keep[i].value = estrdup(getenv(env_keep[i].name)); env_keep[i].value = estrdup(getenv(env_keep[i].name));
environ = NULL; // in place of clearenv environ = NULL;
} }
for (int i = 0; env_mod[i].name; i++) { for (int i = 0; env_mod[i].name; i++) {
@ -315,7 +317,7 @@ int main(int argc, char *argv[])
} }
} }
// do not override, we might be under more levels of 'us' /* Do not override, we might be under more levels of 'us' */
err = setenv("US_USER", my_name, 0); err = setenv("US_USER", my_name, 0);
errno = 0; errno = 0;
@ -403,7 +405,8 @@ static int authenticate(uid_t uid, char ask)
if (!strcmp(p, "x") || *p == '*' || *p == '!') { if (!strcmp(p, "x") || *p == '*' || *p == '!') {
#if defined(__linux__) #if defined(__linux__)
// get exclusive access to shadow /* Get exclusive access to the shadow file, then read
* this should prevent any race conditions */
if (lckpwdf() == -1) if (lckpwdf() == -1)
die("lckpwdf"); die("lckpwdf");
setspent(); setspent();
@ -442,7 +445,9 @@ static int authenticate(uid_t uid, char ask)
break; break;
case 0: case 0:
/* we are still root, drop off permissions before /* we are still root, drop off permissions before
* disasters happen */ * disasters happen, also in case askpass fails
* before sending anything to stdout, terminate tha
* main process since it would hang forever */
if (setuid(uid) == -1) { if (setuid(uid) == -1) {
kill(parent, SIGTERM); kill(parent, SIGTERM);
die("askpass: setuid:"); die("askpass: setuid:");
@ -479,12 +484,13 @@ static int authenticate(uid_t uid, char ask)
fprintf(stderr, "read: %s\n", strerror(errno)); fprintf(stderr, "read: %s\n", strerror(errno));
else else
printf("Password can't be zero length\n"); printf("Password can't be zero length\n");
// we may have been interrupted, wait askpass before bailing /* read() may have been interrupted, wait askpass even tough it
* should not be necessary before bailing */
waitpid(-1, NULL, 0); waitpid(-1, NULL, 0);
exit(EXIT_FAILURE); exit(EXIT_FAILURE);
} }
pass[1023] = '\0'; pass[1023] = '\0';
// remove \n /* Remove the terminating (if there is) \n in password */
int l = strlen(pass); int l = strlen(pass);
if (pass[l-1] == '\n') if (pass[l-1] == '\n')
pass[--l] = '\0'; pass[--l] = '\0';
@ -497,7 +503,7 @@ static int authenticate(uid_t uid, char ask)
} }
char *enc = crypt(pass, hash); char *enc = crypt(pass, hash);
/* clean pass from memory */ /* Remove password from memory, just to be sure */
memset(pass, 0, 1024); memset(pass, 0, 1024);
if (strncmp(hash, enc, 1024)) { if (strncmp(hash, enc, 1024)) {
printf("Authentication failure\n"); printf("Authentication failure\n");
@ -508,6 +514,11 @@ static int authenticate(uid_t uid, char ask)
return 0; return 0;
} }
/* user_to_passwd() and group_to_passwd() both receive the user/group name
* in string form, if the sring begins with '#' then the following number
* is interpreted as the uid/gid and used instead of the name.
* Both functions return a pointer to a passwd/group struct stored inside
* the info structure */
static struct passwd* user_to_passwd(const char *user, struct user_info *info) static struct passwd* user_to_passwd(const char *user, struct user_info *info)
{ {
if (!user) { if (!user) {
@ -560,6 +571,8 @@ static struct group* group_to_grp(const char *group, struct user_info *info)
return gr; return gr;
} }
/* die() emalloc() estrdup() and erealloc() are all helper functions, wrappers
* to respective functions that use die() to give a message and then fail */
void die(const char *fmt, ...) void die(const char *fmt, ...)
{ {
va_list ap; va_list ap;
@ -608,6 +621,8 @@ char *estrdup(const char *s)
return r; return r;
} }
/* Parses the config file and stores the result in a config vector pointed
* by conf of size num */
static int get_config(struct config **conf, int *num) static int get_config(struct config **conf, int *num)
{ {
if (!conf || !num) if (!conf || !num)
@ -692,6 +707,8 @@ static int get_config(struct config **conf, int *num)
c.flags |= FLAG_NOPASS; c.flags |= FLAG_NOPASS;
} else if (!strcmp(t, "nolog")) { } else if (!strcmp(t, "nolog")) {
c.flags |= FLAG_NOLOG; c.flags |= FLAG_NOLOG;
} else {
die("flag %s not recognized at %d", t, i);
} }
} }
if (n < 3) if (n < 3)