git: dd5c76309ad9 - stable/15 - MAC/do: Restore matching the first supplementary group

The branch stable/15 has been updated by olce:

URL: https://cgit.FreeBSD.org/src/commit/?id=dd5c76309ad98c9b058a79f6b674c5dfc44631c1

commit dd5c76309ad98c9b058a79f6b674c5dfc44631c1
Author:     Olivier Certner <olce@FreeBSD.org>
AuthorDate: 2025-08-27 15:22:26 +0000
Commit:     Olivier Certner <olce@FreeBSD.org>
CommitDate: 2025-09-23 12:02:43 +0000

    MAC/do: Restore matching the first supplementary group
    
    As 'cr_gid' was in fact stored in cr_groups[0],
    rule_grant_supplementary_groups() would loop only on further elements of
    cr_groups[].  Now that cr_groups[0] is not 'cr_gid' anymore, but some
    supplementary group, take it into account.
    
    Fixes:          be1f7435ef218b1d ("kern: start tracking cr_gid outside of cr_groups[]")
    MFC after:      5 days
    MFC to:         stable/15
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D52271
    
    (cherry picked from commit d39756f23fe223d14ff00b1392ba39e94d5eadbc)
---
 sys/security/mac_do/mac_do.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/security/mac_do/mac_do.c b/sys/security/mac_do/mac_do.c
index 7a5ac2e01f75..6f3e63d06198 100644
--- a/sys/security/mac_do/mac_do.c
+++ b/sys/security/mac_do/mac_do.c
@@ -1650,7 +1650,7 @@ rule_grant_supplementary_groups(const struct rule *const rule,
 	const bool current_has_supp = (gid_flags & MDF_CURRENT) != 0 &&
 	    (gid_flags & MDF_SUPP_MASK) != 0;
 	id_nb_t rule_idx = 0;
-	int old_idx = 1, new_idx = 1;
+	int old_idx = 0, new_idx = 0;
 
 	if ((gid_flags & MDF_ANY_SUPP) != 0 &&
 	    (gid_flags & MDF_MAY_REJ_SUPP) == 0)