shadow password fixes: empty fields should read as -1 not 0

[musl] / src / passwd / getspnam_r.c

diff --git a/src/passwd/getspnam_r.c b/src/passwd/getspnam_r.c
index 1dd39ce..9e29aa9 100644 (file)
--- a/src/passwd/getspnam_r.c
+++ b/src/passwd/getspnam_r.c
@@ -1,5 +1,7 @@
 #include <fcntl.h>
 #include <unistd.h>
+#include <sys/stat.h>
+#include <ctype.h>
 #include "pwf.h"
 
 /* This implementation support Openwall-style TCB passwords in place of
@@ -9,6 +11,11 @@
  * file. It also avoids any allocation to prevent memory-exhaustion
  * attacks via huge TCB shadow files. */
 
+static long xatol(const char *s)
+{
+       return isdigit(*s) ? atol(s) : -1;
+}
+
 int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct spwd **res)
 {
        char path[20+NAME_MAX];
@@ -34,8 +41,9 @@ int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct
 
        fd = open(path, O_RDONLY|O_NOFOLLOW|O_NONBLOCK);
        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"))) {
                        close(fd);
                        return errno;
                }
@@ -62,25 +70,25 @@ int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct
                *s++ = 0; sp->sp_pwdp = s;
                if (!(s = strchr(s, ':'))) continue;
 
-               *s++ = 0; sp->sp_lstchg = atol(s);
+               *s++ = 0; sp->sp_lstchg = xatol(s);
                if (!(s = strchr(s, ':'))) continue;
 
-               *s++ = 0; sp->sp_min = atol(s);
+               *s++ = 0; sp->sp_min = xatol(s);
                if (!(s = strchr(s, ':'))) continue;
 
-               *s++ = 0; sp->sp_max = atol(s);
+               *s++ = 0; sp->sp_max = xatol(s);
                if (!(s = strchr(s, ':'))) continue;
 
-               *s++ = 0; sp->sp_warn = atol(s);
+               *s++ = 0; sp->sp_warn = xatol(s);
                if (!(s = strchr(s, ':'))) continue;
 
-               *s++ = 0; sp->sp_inact = atol(s);
+               *s++ = 0; sp->sp_inact = xatol(s);
                if (!(s = strchr(s, ':'))) continue;
 
-               *s++ = 0; sp->sp_expire = atol(s);
+               *s++ = 0; sp->sp_expire = xatol(s);
                if (!(s = strchr(s, ':'))) continue;
 
-               *s++ = 0; sp->sp_flag = atol(s);
+               *s++ = 0; sp->sp_flag = xatol(s);
                *res = sp;
                break;
        }