From 26f96ca10ad0ec5da9b05b99de1e1ccea15a11be Mon Sep 17 00:00:00 2001 From: "djm@openbsd.org" Date: Fri, 15 Jun 2018 07:01:11 +0000 Subject: [PATCH] upstream: invalidate supplemental group cache used by temporarily_use_uid() when the target uid differs; could cause failure to read authorized_keys under some configurations. patch by Jakub Jelen via bz2873; ok dtucker, markus OpenBSD-Commit-ID: 48a345f0ee90f6c465a078eb5e89566b23abd8a1 --- uidswap.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/uidswap.c b/uidswap.c index 8bf6b244e..1430b822a 100644 --- a/uidswap.c +++ b/uidswap.c @@ -49,6 +49,7 @@ static gid_t saved_egid = 0; /* Saved effective uid. */ static int privileged = 0; static int temporarily_use_uid_effective = 0; +static uid_t user_groups_uid; static gid_t *saved_egroups = NULL, *user_groups = NULL; static int saved_egroupslen = -1, user_groupslen = -1; @@ -92,10 +93,11 @@ temporarily_use_uid(struct passwd *pw) fatal("getgroups: %.100s", strerror(errno)); } else { /* saved_egroupslen == 0 */ free(saved_egroups); + saved_egroups = NULL; } /* set and save the user's groups */ - if (user_groupslen == -1) { + if (user_groupslen == -1 || user_groups_uid != pw->pw_uid) { if (initgroups(pw->pw_name, pw->pw_gid) < 0) fatal("initgroups: %s: %.100s", pw->pw_name, strerror(errno)); @@ -110,7 +112,9 @@ temporarily_use_uid(struct passwd *pw) fatal("getgroups: %.100s", strerror(errno)); } else { /* user_groupslen == 0 */ free(user_groups); + user_groups = NULL; } + user_groups_uid = pw->pw_uid; } /* Set the effective uid to the given (unprivileged) uid. */ if (setgroups(user_groupslen, user_groups) < 0)