util: Reallocate larger buffer if getpwuid_r() returns ERANGE

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Bjoern Jacke <bjacke@samba.org>
Autobuild-User(master): Martin Schwenke <martins@samba.org>
Autobuild-Date(master): Tue Jun  9 21:07:24 UTC 2020 on sn-devel-184

(cherry picked from commit ddac6b2eb4adaec8fc5e25ca07387d2b9417764c)

diff --git a/lib/util/util_paths.c b/lib/util/util_paths.c
index 9bc6df37e5d484e4671e50894e9ba0fb72a1cfea..72cc0aab8de566ba03636a828b74b1c7715285d2 100644 (file)
--- a/lib/util/util_paths.c
+++ b/lib/util/util_paths.c
@@ -86,6 +86,19 @@ static char *get_user_home_dir(TALLOC_CTX *mem_ctx)
        }
 
        rc = getpwuid_r(getuid(), &pwd, buf, len, &pwdbuf);
+       while (rc == ERANGE) {
+               size_t newlen = 2 * len;
+               if (newlen < len) {
+                       /* Overflow */
+                       goto done;
+               }
+               len = newlen;
+               buf = talloc_realloc_size(mem_ctx, buf, len);
+               if (buf == NULL) {
+                       goto done;
+               }
+               rc = getpwuid_r(getuid(), &pwd, buf, len, &pwdbuf);
+       }
        if (rc != 0 || pwdbuf == NULL ) {
                const char *szPath = getenv("HOME");
                if (szPath == NULL) {