diff options
| author | John Johansen <john.johansen@canonical.com> | 2022-09-09 16:00:09 -0700 |
|---|---|---|
| committer | John Johansen <john.johansen@canonical.com> | 2023-10-18 15:49:02 -0700 |
| commit | fa9b63adabcfa9b724120ef3352cf6fb82b4b9a5 (patch) | |
| tree | dc093ea12c7ae548e981bc1f675d7f974a6366f0 /security/apparmor/lsm.c | |
| parent | 2d9da9b188b8cd3b579d7ef5ba5d334be9dd38fc (diff) | |
apparmor: add user namespace creation mediation
Unprivileged user namespace creation is often used as a first step
in privilege escalation attacks. Instead of disabling it at the
sysrq level, which blocks its legitimate use as for setting up a sandbox,
allow control on a per domain basis.
This allows an admin to quickly lock down a system while also still
allowing legitimate use.
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Diffstat (limited to 'security/apparmor/lsm.c')
| -rw-r--r-- | security/apparmor/lsm.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 518576ae3cfb..c61835bd7db9 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -836,6 +836,27 @@ static int apparmor_task_kill(struct task_struct *target, struct kernel_siginfo return error; } +static int apparmor_userns_create(const struct cred *cred) +{ + struct aa_label *label; + struct aa_profile *profile; + int error = 0; + DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_TASK, AA_CLASS_NS, + OP_USERNS_CREATE); + + ad.subj_cred = current_cred(); + + label = begin_current_label_crit_section(); + if (!unconfined(label)) { + error = fn_for_each(label, profile, + aa_profile_ns_perm(profile, &ad, + AA_USERNS_CREATE)); + } + end_current_label_crit_section(label); + + return error; +} + /** * apparmor_sk_alloc_security - allocate and attach the sk_security field */ @@ -1313,6 +1334,7 @@ static struct security_hook_list apparmor_hooks[] __ro_after_init = { LSM_HOOK_INIT(task_getsecid_obj, apparmor_task_getsecid_obj), LSM_HOOK_INIT(task_setrlimit, apparmor_task_setrlimit), LSM_HOOK_INIT(task_kill, apparmor_task_kill), + LSM_HOOK_INIT(userns_create, apparmor_userns_create), #ifdef CONFIG_AUDIT LSM_HOOK_INIT(audit_rule_init, aa_audit_rule_init), @@ -1784,6 +1806,7 @@ static int apparmor_dointvec(struct ctl_table *table, int write, } static struct ctl_table apparmor_sysctl_table[] = { +#ifdef CONFIG_USER_NS { .procname = "unprivileged_userns_apparmor_policy", .data = &unprivileged_userns_apparmor_policy, @@ -1791,6 +1814,7 @@ static struct ctl_table apparmor_sysctl_table[] = { .mode = 0600, .proc_handler = apparmor_dointvec, }, +#endif /* CONFIG_USER_NS */ { .procname = "apparmor_display_secid_mode", .data = &apparmor_display_secid_mode, @@ -1805,7 +1829,6 @@ static struct ctl_table apparmor_sysctl_table[] = { .mode = 0600, .proc_handler = apparmor_dointvec, }, - { } }; |