set errno when getpw*_r, getgr*_r, and getspnam_r fail

[musl] / src / passwd / getspnam_r.c

diff --git a/src/passwd/getspnam_r.c b/src/passwd/getspnam_r.c
index 1dd39ce..e488b67 100644 (file)
--- a/src/passwd/getspnam_r.c
+++ b/src/passwd/getspnam_r.c
@@ -1,5 +1,8 @@
 #include <fcntl.h>
 #include <unistd.h>
+#include <sys/stat.h>
+#include <ctype.h>
+#include <pthread.h>
 #include "pwf.h"
 
 /* This implementation support Openwall-style TCB passwords in place of
@@ -9,6 +12,52 @@
  * file. It also avoids any allocation to prevent memory-exhaustion
  * attacks via huge TCB shadow files. */
 
+static long xatol(char **s)
+{
+       long x;
+       if (**s == ':' || **s == '\n') return -1;
+       for (x=0; **s-'0'<10U; ++*s) x=10*x+(**s-'0');
+       return x;
+}
+
+int __parsespent(char *s, struct spwd *sp)
+{
+       sp->sp_namp = s;
+       if (!(s = strchr(s, ':'))) return -1;
+       *s = 0;
+
+       sp->sp_pwdp = ++s;
+       if (!(s = strchr(s, ':'))) return -1;
+       *s = 0;
+
+       s++; sp->sp_lstchg = xatol(&s);
+       if (*s != ':') return -1;
+
+       s++; sp->sp_min = xatol(&s);
+       if (*s != ':') return -1;
+
+       s++; sp->sp_max = xatol(&s);
+       if (*s != ':') return -1;
+
+       s++; sp->sp_warn = xatol(&s);
+       if (*s != ':') return -1;
+
+       s++; sp->sp_inact = xatol(&s);
+       if (*s != ':') return -1;
+
+       s++; sp->sp_expire = xatol(&s);
+       if (*s != ':') return -1;
+
+       s++; sp->sp_flag = xatol(&s);
+       if (*s != '\n') return -1;
+       return 0;
+}
+
+static void cleanup(void *p)
+{
+       fclose(p);
+}
+
 int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct spwd **res)
 {
        char path[20+NAME_MAX];
@@ -16,36 +65,41 @@ int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct
        int rv = 0;
        int fd;
        size_t k, l = strlen(name);
-       char *s;
        int skip = 0;
+       int cs;
 
        *res = 0;
 
        /* Disallow potentially-malicious user names */
        if (*name=='.' || strchr(name, '/') || !l)
-               return EINVAL;
+               return errno = EINVAL;
 
        /* Buffer size must at least be able to hold name, plus some.. */
-       if (size < l+100) return ERANGE;
+       if (size < l+100)
+               return errno = EINVAL;
 
        /* Protect against truncation */
        if (snprintf(path, sizeof path, "/etc/tcb/%s/shadow", name) >= sizeof path)
-               return EINVAL;
+               return errno = EINVAL;
 
-       fd = open(path, O_RDONLY|O_NOFOLLOW|O_NONBLOCK);
+       fd = open(path, O_RDONLY|O_NOFOLLOW|O_NONBLOCK|O_CLOEXEC);
        if (fd >= 0) {
-               f = fdopen(fd, "rb");
-               if (!f) {
+               struct stat st = { 0 };
+               errno = EINVAL;
+               if (fstat(fd, &st) || !S_ISREG(st.st_mode) || !(f = fdopen(fd, "rb"))) {
+                       pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
                        close(fd);
+                       pthread_setcancelstate(cs, 0);
                        return errno;
                }
        } else {
-               f = fopen("/etc/shadow", "rb");
+               f = fopen("/etc/shadow", "rbe");
                if (!f) return errno;
        }
 
+       pthread_cleanup_push(cleanup, f);
        while (fgets(buf, size, f) && (k=strlen(buf))>0) {
-               if (skip || strncmp(name, buf, l)) {
+               if (skip || strncmp(name, buf, l) || buf[l]!=':') {
                        skip = buf[k-1] != '\n';
                        continue;
                }
@@ -53,37 +107,12 @@ int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct
                        rv = ERANGE;
                        break;
                }
-               buf[k-1] = 0;
-
-               s = buf;
-               sp->sp_namp = s;
-               if (!(s = strchr(s, ':'))) continue;
-
-               *s++ = 0; sp->sp_pwdp = s;
-               if (!(s = strchr(s, ':'))) continue;
-
-               *s++ = 0; sp->sp_lstchg = atol(s);
-               if (!(s = strchr(s, ':'))) continue;
-
-               *s++ = 0; sp->sp_min = atol(s);
-               if (!(s = strchr(s, ':'))) continue;
-
-               *s++ = 0; sp->sp_max = atol(s);
-               if (!(s = strchr(s, ':'))) continue;
-
-               *s++ = 0; sp->sp_warn = atol(s);
-               if (!(s = strchr(s, ':'))) continue;
-
-               *s++ = 0; sp->sp_inact = atol(s);
-               if (!(s = strchr(s, ':'))) continue;
-
-               *s++ = 0; sp->sp_expire = atol(s);
-               if (!(s = strchr(s, ':'))) continue;
 
-               *s++ = 0; sp->sp_flag = atol(s);
+               if (__parsespent(buf, sp) < 0) continue;
                *res = sp;
                break;
        }
-       fclose(f);
+       pthread_cleanup_pop(1);
+       if (rv) errno = rv;
        return rv;
 }