fix getpwnam() thread safe issue

Signed-off-by: Donghwa Jeong <dh48.jeong@samsung.com>

diff --git a/src/lxc/tools/lxc_unshare.c b/src/lxc/tools/lxc_unshare.c
index 9c38f537ffca02148eeaf58b2477c1e463b6b1a0..5e1775f5eaa22d3aaec00b51c717c12be42591f3 100644 (file)
--- a/src/lxc/tools/lxc_unshare.c
+++ b/src/lxc/tools/lxc_unshare.c
@@ -68,29 +68,51 @@ static void usage(char *cmd)
 static bool lookup_user(const char *optarg, uid_t *uid)
 {
        char name[MAXPATHLEN];
-       struct passwd *pwent = NULL;
+       struct passwd pwent;
+       struct passwd *pwentp = NULL;
+       char *buf;
+       size_t bufsize;
+       int ret;
 
        if (!optarg || (optarg[0] == '\0'))
                return false;
 
+       bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);
+       if (bufsize == -1)
+               bufsize = 1024;
+
+       buf = malloc(bufsize);
+       if (!buf)
+               return false;
+
        if (sscanf(optarg, "%u", uid) < 1) {
                /* not a uid -- perhaps a username */
                if (sscanf(optarg, "%s", name) < 1)
                        return false;
 
-               pwent = getpwnam(name);
-               if (!pwent) {
+               ret = getpwnam_r(name, &pwent, buf, bufsize, &pwentp);
+               if (!pwentp) {
+                       if (ret == 0)
+                               fprintf(stderr, "could not find matched password record\n");
+
                        fprintf(stderr, "invalid username %s\n", name);
+                       free(buf);
                        return false;
                }
-               *uid = pwent->pw_uid;
+               *uid = pwent.pw_uid;
        } else {
-               pwent = getpwuid(*uid);
-               if (!pwent) {
+               ret = getpwuid_r(*uid, &pwent, buf, bufsize, &pwentp);
+               if (!pwentp) {
+                       if (ret == 0)
+                               fprintf(stderr, "could not find matched password record\n");
+
                        fprintf(stderr, "invalid uid %u\n", *uid);
+                       free(buf);
                        return false;
                }
        }
+
+       free(buf);
        return true;
 }