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linux: add some check for NULL pointers before accessing them #1949

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linux: add some check for NULL pointers before accessing them #1949

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b1a7172
linux: check for [ug]id_mappings before accessing them
giuseppe Jan 7, 2026
488f301
linux: check for def->linux
giuseppe Jan 7, 2026
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19 changes: 17 additions & 2 deletions src/libcrun/linux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1754,6 +1754,9 @@ create_missing_devs (libcrun_container_t *container, bool binds, libcrun_error_t
dev_fds = get_private_data (container)->dev_fds;
get_private_data (container)->dev_fds = NULL;

if (! def || ! def->linux)
return 0;

devfd = openat (get_private_data (container)->rootfsfd, "dev", O_CLOEXEC | O_PATH | O_DIRECTORY);
if (UNLIKELY (devfd < 0))
return crun_make_error (err, errno, "open `/dev` directory in `%s`", rootfs);
Expand Down Expand Up @@ -1839,6 +1842,9 @@ do_masked_and_readonly_paths (libcrun_container_t *container, libcrun_error_t *e
int ret;
runtime_spec_schema_config_schema *def = container->container_def;

if (! def || ! def->linux)
return 0;

for (i = 0; i < def->linux->masked_paths_len; i++)
{
ret = do_masked_or_readonly_path (container, def->linux->masked_paths[i], false, false, err);
Expand Down Expand Up @@ -2689,7 +2695,7 @@ libcrun_set_mounts (struct container_entrypoint_s *entrypoint_args, libcrun_cont
if (rootfs == NULL || def->mounts == NULL)
return 0;

if (def->linux->rootfs_propagation)
if (def->linux && def->linux->rootfs_propagation)
rootfs_propagation = get_mount_flags (def->linux->rootfs_propagation, 0, NULL, NULL, NULL, NULL);

if ((rootfs_propagation & ALL_PROPAGATIONS_NO_REC) == 0)
Expand Down Expand Up @@ -3130,6 +3136,9 @@ libcrun_set_usernamespace (libcrun_container_t *container, pid_t pid, libcrun_er
if ((get_private_data (container)->unshare_flags & CLONE_NEWUSER) == 0)
return 0;

if (! def || ! def->linux)
return 0;

if (def->linux->uid_mappings_len)
{
ret = format_mount_mappings (&uid_map, def->linux->uid_mappings, def->linux->uid_mappings_len, &uid_map_len, err);
Expand Down Expand Up @@ -4366,16 +4375,22 @@ get_id_in_user_namespace (uid_t id, bool is_uid, runtime_spec_schema_config_sche
size_t len;
size_t i;

if (! def || ! def->linux)
goto exit;

mappings = is_uid ? def->linux->uid_mappings : def->linux->gid_mappings;
len = is_uid ? def->linux->uid_mappings_len : def->linux->gid_mappings_len;

if (! mappings)
goto exit;

for (i = 0; i < len; i++)
{
if (mappings[i]->container_id <= id
&& id < mappings[i]->container_id + mappings[i]->size)
return id - mappings[i]->container_id + mappings[i]->host_id;
}

exit:
return is_uid ? get_overflow_uid () : get_overflow_gid ();
}

Expand Down