[PATCH] userspec: help fix GNU ‘id’ incompatibility

[Paul Eggert]

* lib/userspec.c (parse_with_separator):
Don’t set *username to a numeric string that is not a user name,
and similarly for *groupname.  Needed to fix Bug#53631.
---
 ChangeLog      | 7 +++++++
 lib/userspec.c | 2 ++
 2 files changed, 9 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index a202950bd9..5445802ea2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2022-02-04  Paul Eggert  <egg...@cs.ucla.edu>
+
+       userspec: help fix GNU ‘id’ incompatibility
+       * lib/userspec.c (parse_with_separator):
+       Don’t set *username to a numeric string that is not a user name,
+       and similarly for *groupname.  Needed to fix Bug#53631.
+
 2022-01-30  Pádraig Brady  <p...@draigbrady.com>
 
        argmatch: add variants that only match full argument
diff --git a/lib/userspec.c b/lib/userspec.c
index 99ac93bb53..f05ccbe635 100644
--- a/lib/userspec.c
+++ b/lib/userspec.c
@@ -161,6 +161,7 @@ parse_with_separator (char const *spec, char const 
*separator,
       pwd = (*u == '+' ? NULL : getpwnam (u));
       if (pwd == NULL)
         {
+          username = NULL;
           bool use_login_group = (separator != NULL && g == NULL);
           if (use_login_group)
             {
@@ -202,6 +203,7 @@ parse_with_separator (char const *spec, char const 
*separator,
       grp = (*g == '+' ? NULL : getgrnam (g));
       if (grp == NULL)
         {
+          groupname = NULL;
           unsigned long int tmp;
           if (xstrtoul (g, NULL, 10, &tmp, "") == LONGINT_OK
               && tmp <= MAXGID && (gid_t) tmp != (gid_t) -1)
-- 
2.34.1