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=== Description (from pull-request) ===
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
From b8885e74384f73ae52e44b5a8b77932ce8cc3a92 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brau...@ubuntu.com>
Date: Fri, 27 Mar 2020 09:37:48 +0100
Subject: [PATCH] conf: rework and fix leak in userns_exec_1()
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
---
src/lxc/conf.c | 62 +++++++++++++++++++++++---------------------------
1 file changed, 28 insertions(+), 34 deletions(-)
diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 8cd06abf90..b084cb88ee 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -3846,19 +3846,18 @@ struct userns_fn_data {
static int run_userns_fn(void *data)
{
+ struct userns_fn_data *d = data;
int ret;
char c;
- struct userns_fn_data *d = data;
- /* Close write end of the pipe. */
- close(d->p[1]);
+ close_prot_errno_disarm(d->p[1]);
- /* Wait for parent to finish establishing a new mapping in the user
+ /*
+ * Wait for parent to finish establishing a new mapping in the user
* namespace we are executing in.
*/
ret = lxc_read_nointr(d->p[0], &c, 1);
- /* Close read end of the pipe. */
- close(d->p[0]);
+ close_prot_errno_disarm(d->p[0]);
if (ret != 1)
return -1;
@@ -4033,7 +4032,8 @@ static struct lxc_list *get_minimal_idmap(const struct
lxc_conf *conf)
return move_ptr(idmap);
}
-/* Run a function in a new user namespace.
+/*
+ * Run a function in a new user namespace.
* The caller's euid/egid will be mapped if it is not already.
* Afaict, userns_exec_1() is only used to operate based on privileges for the
* user's own {g,u}id on the host and for the container root's unmapped
{g,u}id.
@@ -4047,30 +4047,29 @@ static struct lxc_list *get_minimal_idmap(const struct
lxc_conf *conf)
int userns_exec_1(const struct lxc_conf *conf, int (*fn)(void *), void *data,
const char *fn_name)
{
- pid_t pid;
- int p[2];
- struct userns_fn_data d;
- struct lxc_list *idmap;
+ __do_free struct lxc_list *idmap = NULL;
int ret = -1, status = -1;
char c = '1';
+ pid_t pid;
+ int pipe_fds[2];
+ struct userns_fn_data d;
if (!conf)
return -EINVAL;
idmap = get_minimal_idmap(conf);
if (!idmap)
- return -1;
+ return ret_errno(ENOENT);
- ret = pipe2(p, O_CLOEXEC);
- if (ret < 0) {
- SYSERROR("Failed to create pipe");
- return -1;
- }
- d.fn = fn;
- d.fn_name = fn_name;
- d.arg = data;
- d.p[0] = p[0];
- d.p[1] = p[1];
+ ret = pipe2(pipe_fds, O_CLOEXEC);
+ if (ret < 0)
+ return -errno;
+
+ d.fn = fn;
+ d.fn_name = fn_name;
+ d.arg = data;
+ d.p[0] = pipe_fds[0];
+ d.p[1] = pipe_fds[1];
/* Clone child in new user namespace. */
pid = lxc_raw_clone_cb(run_userns_fn, &d, CLONE_NEWUSER, NULL);
@@ -4079,21 +4078,17 @@ int userns_exec_1(const struct lxc_conf *conf, int
(*fn)(void *), void *data,
goto on_error;
}
- close(p[0]);
- p[0] = -1;
+ close_prot_errno_disarm(pipe_fds[0]);
if (lxc_log_get_level() == LXC_LOG_LEVEL_TRACE ||
conf->loglevel == LXC_LOG_LEVEL_TRACE) {
struct id_map *map;
struct lxc_list *it;
- lxc_list_for_each (it, idmap) {
+ lxc_list_for_each(it, idmap) {
map = it->elem;
- TRACE("Establishing %cid mapping for \"%d\" in new "
- "user namespace: nsuid %lu - hostid %lu - range "
- "%lu",
- (map->idtype == ID_TYPE_UID) ? 'u' : 'g', pid,
- map->nsid, map->hostid, map->range);
+ TRACE("Establishing %cid mapping for \"%d\" in new user
namespace: nsuid %lu - hostid %lu - range %lu",
+ (map->idtype == ID_TYPE_UID) ? 'u' : 'g', pid,
map->nsid, map->hostid, map->range);
}
}
@@ -4105,15 +4100,14 @@ int userns_exec_1(const struct lxc_conf *conf, int
(*fn)(void *), void *data,
}
/* Tell child to proceed. */
- if (lxc_write_nointr(p[1], &c, 1) != 1) {
+ if (lxc_write_nointr(pipe_fds[1], &c, 1) != 1) {
SYSERROR("Failed telling child process \"%d\" to proceed", pid);
goto on_error;
}
on_error:
- if (p[0] != -1)
- close(p[0]);
- close(p[1]);
+ close_prot_errno_disarm(pipe_fds[0]);
+ close_prot_errno_disarm(pipe_fds[1]);
/* Wait for child to finish. */
if (pid > 0)
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