pkg: use lib/apk/exec as the package script execution directory

var/cache is also reported to be mounted noexec on hardened
systems. Document some of the issues, and use lib/apk/exec
for the time being. Keep the scripts still in separate directory
from lib/apk so we can just delete directory if needed.

fixes #6591
cute-signatures
Timo Teräs 2022-02-24 14:29:38 +02:00
parent e4dc2373d6
commit 62bc43d2a4
1 changed files with 15 additions and 11 deletions

View File

@ -788,6 +788,14 @@ void apk_ipkg_run_script(struct apk_installed_package *ipkg,
struct apk_database *db,
unsigned int type, char **argv)
{
// script_exec_dir is the directory to which the script is extracted,
// executed from, and removed. It needs to not be 'noexec' mounted, and
// preferably a tmpfs disk, or something that could be wiped in boot.
// Originally this was /tmp, but it is often suggested to be 'noexec'.
// Then changed ro /var/cache/misc, but that is also often 'noexec'.
// /run was consider as it's tmpfs, but it also might be changing to 'noexec'.
// So use for now /lib/apk/exec even if it is not of temporary nature.
static const char script_exec_dir[] = "lib/apk/exec";
struct apk_out *out = &db->ctx->out;
struct apk_package *pkg = ipkg->pkg;
char fn[PATH_MAX];
@ -798,9 +806,8 @@ void apk_ipkg_run_script(struct apk_installed_package *ipkg,
argv[0] = (char *) apk_script_types[type];
/* Avoid /tmp as it can be mounted noexec */
snprintf(fn, sizeof(fn), "var/cache/misc/" PKG_VER_FMT ".%s",
PKG_VER_PRINTF(pkg),
snprintf(fn, sizeof(fn), "%s/" PKG_VER_FMT ".%s",
script_exec_dir, PKG_VER_PRINTF(pkg),
apk_script_types[type]);
if ((db->ctx->flags & (APK_NO_SCRIPTS | APK_SIMULATE)) != 0)
@ -808,17 +815,14 @@ void apk_ipkg_run_script(struct apk_installed_package *ipkg,
if (!db->script_dirs_checked) {
db->script_dirs_checked = 1;
if (faccessat(db->root_fd, "tmp", F_OK, 0) != 0)
mkdirat(db->root_fd, "tmp", 01777);
if (faccessat(root_fd, "tmp", F_OK, 0) != 0)
mkdirat(root_fd, "tmp", 01777);
if (faccessat(root_fd, script_exec_dir, F_OK, 0) != 0)
mkdirat(root_fd, script_exec_dir, 0700);
make_device_tree(db);
if (faccessat(db->root_fd, "var/cache/misc", F_OK, 0) != 0) {
mkdirat(root_fd, "var", 0755);
mkdirat(root_fd, "var/cache", 0755);
mkdirat(root_fd, "var/cache/misc", 0755);
}
}
apk_msg(out, "Executing %s", &fn[15]);
apk_msg(out, "Executing %s", &fn[strlen(script_exec_dir)+1]);
fd = openat(root_fd, fn, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC, 0755);
if (fd < 0) {
fd = openat(root_fd, fn, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC, 0755);