From 699b9dcb4e1ab66703bc22c0e3eed16b650895c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Fri, 20 Oct 2017 13:00:12 +0200
Subject: [PATCH] core/dynamic-user: use gid from pwnam if a static user was
found
Fixes #7133.
v2:
- update based on review
(cherry picked from commit c2983a7fdd027b6241b8c8814706c6ea9768a34c)
---
src/core/dynamic-user.c | 53 +++++++++++++++++++++++++++++--------------------
1 file changed, 32 insertions(+), 21 deletions(-)
diff --git a/src/core/dynamic-user.c b/src/core/dynamic-user.c
index 0f4ec15721..ce84f8d41a 100644
--- a/src/core/dynamic-user.c
+++ b/src/core/dynamic-user.c
@@ -435,15 +435,22 @@ static void unlockfp(int *fd_lock) {
*fd_lock = -1;
}
-static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *ret, bool is_user) {
+static int dynamic_user_realize(
+ DynamicUser *d,
+ char **suggested_dirs,
+ uid_t *ret_uid, gid_t *ret_gid,
+ bool is_user) {
_cleanup_(unlockfp) int storage_socket0_lock = -1;
_cleanup_close_ int uid_lock_fd = -1;
_cleanup_close_ int etc_passwd_lock_fd = -1;
- uid_t uid = UID_INVALID;
+ uid_t num = UID_INVALID; /* a uid if is_user, and a gid otherwise */
+ gid_t gid = GID_INVALID; /* a gid if is_user, ignored otherwise */
int r;
assert(d);
+ assert(is_user == !!ret_uid);
+ assert(ret_gid);
/* Acquire a UID for the user name. This will allocate a UID for the user name if the user doesn't exist
* yet. If it already exists its existing UID/GID will be reused. */
@@ -452,7 +459,7 @@ static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *re
if (r < 0)
return r;
- r = dynamic_user_pop(d, &uid, &uid_lock_fd);
+ r = dynamic_user_pop(d, &num, &uid_lock_fd);
if (r < 0) {
int new_uid_lock_fd;
uid_t new_uid;
@@ -472,7 +479,7 @@ static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *re
return etc_passwd_lock_fd;
/* First, let's parse this as numeric UID */
- r = parse_uid(d->name, &uid);
+ r = parse_uid(d->name, &num);
if (r < 0) {
struct passwd *p;
struct group *g;
@@ -480,9 +487,10 @@ static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *re
if (is_user) {
/* OK, this is not a numeric UID. Let's see if there's a user by this name */
p = getpwnam(d->name);
- if (p)
- uid = p->pw_uid;
- else {
+ if (p) {
+ num = p->pw_uid;
+ gid = p->pw_gid;
+ } else {
/* if the user does not exist but the group with the same name exists, refuse operation */
g = getgrnam(d->name);
if (g)
@@ -492,7 +500,7 @@ static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *re
/* Let's see if there's a group by this name */
g = getgrnam(d->name);
if (g)
- uid = (uid_t) g->gr_gid;
+ num = (uid_t) g->gr_gid;
else {
/* if the group does not exist but the user with the same name exists, refuse operation */
p = getpwnam(d->name);
@@ -502,10 +510,10 @@ static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *re
}
}
- if (uid == UID_INVALID) {
+ if (num == UID_INVALID) {
/* No static UID assigned yet, excellent. Let's pick a new dynamic one, and lock it. */
- uid_lock_fd = pick_uid(suggested_dirs, d->name, &uid);
+ uid_lock_fd = pick_uid(suggested_dirs, d->name, &num);
if (uid_lock_fd < 0)
return uid_lock_fd;
}
@@ -513,7 +521,7 @@ static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *re
/* So, we found a working UID/lock combination. Let's see if we actually still need it. */
r = lockfp(d->storage_socket[0], &storage_socket0_lock);
if (r < 0) {
- unlink_uid_lock(uid_lock_fd, uid, d->name);
+ unlink_uid_lock(uid_lock_fd, num, d->name);
return r;
}
@@ -521,7 +529,7 @@ static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *re
if (r < 0) {
if (r != -EAGAIN) {
/* OK, something bad happened, let's get rid of the bits we acquired. */
- unlink_uid_lock(uid_lock_fd, uid, d->name);
+ unlink_uid_lock(uid_lock_fd, num, d->name);
return r;
}
@@ -530,10 +538,10 @@ static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *re
/* Hmm, so as it appears there's now something stored in the storage socket. Throw away what we
* acquired, and use what's stored now. */
- unlink_uid_lock(uid_lock_fd, uid, d->name);
+ unlink_uid_lock(uid_lock_fd, num, d->name);
safe_close(uid_lock_fd);
- uid = new_uid;
+ num = new_uid;
uid_lock_fd = new_uid_lock_fd;
}
}
@@ -541,11 +549,16 @@ static int dynamic_user_realize(DynamicUser *d, char **suggested_dirs, uid_t *re
/* If the UID/GID was already allocated dynamically, push the data we popped out back in. If it was already
* allocated statically, push the UID back too, but do not push the lock fd in. If we allocated the UID
* dynamically right here, push that in along with the lock fd for it. */
- r = dynamic_user_push(d, uid, uid_lock_fd);
+ r = dynamic_user_push(d, num, uid_lock_fd);
if (r < 0)
return r;
- *ret = uid;
+ if (is_user) {
+ *ret_uid = num;
+ *ret_gid = gid != GID_INVALID ? gid : num;
+ } else
+ *ret_gid = num;
+
return 0;
}
@@ -831,21 +844,19 @@ int dynamic_creds_realize(DynamicCreds *creds, char **suggested_paths, uid_t *ui
/* Realize both the referenced user and group */
if (creds->user) {
- r = dynamic_user_realize(creds->user, suggested_paths, &u, true);
+ r = dynamic_user_realize(creds->user, suggested_paths, &u, &g, true);
if (r < 0)
return r;
}
if (creds->group && creds->group != creds->user) {
- r = dynamic_user_realize(creds->group, suggested_paths, &g, false);
+ r = dynamic_user_realize(creds->group, suggested_paths, NULL, &g, false);
if (r < 0)
return r;
- } else
- g = u;
+ }
*uid = u;
*gid = g;
-
return 0;
}