From c29bceb3967398cf2ac8bf8edf9634fdb722df7d Mon Sep 17 00:00:00 2001 From: John Johansen Date: Thu, 12 Apr 2012 16:47:51 -0500 Subject: [PATCH] Fix execve behavior apparmor for PR_{GET,SET}_NO_NEW_PRIVS Add support for AppArmor to explicitly fail requested domain transitions if NO_NEW_PRIVS is set and the task is not unconfined. Transitions from unconfined are still allowed because this always results in a reduction of privileges. Acked-by: Eric Paris Signed-off-by: Will Drewry Signed-off-by: John Johansen Signed-off-by: Andy Lutomirski v18: new acked-by, new description Signed-off-by: James Morris --- security/apparmor/domain.c | 39 ++++++++++++++++++++++++++++++++++---- 1 file changed, 35 insertions(+), 4 deletions(-) diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c index 18c88d06e881..b81ea10a17a3 100644 --- a/security/apparmor/domain.c +++ b/security/apparmor/domain.c @@ -360,10 +360,6 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm) if (bprm->cred_prepared) return 0; - /* XXX: no_new_privs is not usable with AppArmor yet */ - if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) - return -EPERM; - cxt = bprm->cred->security; BUG_ON(!cxt); @@ -398,6 +394,11 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm) new_profile = find_attach(ns, &ns->base.profiles, name); if (!new_profile) goto cleanup; + /* + * NOTE: Domain transitions from unconfined are allowed + * even when no_new_privs is set because this aways results + * in a further reduction of permissions. + */ goto apply; } @@ -459,6 +460,16 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm) /* fail exec */ error = -EACCES; + /* + * Policy has specified a domain transition, if no_new_privs then + * fail the exec. + */ + if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) { + aa_put_profile(new_profile); + error = -EPERM; + goto cleanup; + } + if (!new_profile) goto audit; @@ -613,6 +624,14 @@ int aa_change_hat(const char *hats[], int count, u64 token, bool permtest) const char *target = NULL, *info = NULL; int error = 0; + /* + * Fail explicitly requested domain transitions if no_new_privs. + * There is no exception for unconfined as change_hat is not + * available. + */ + if (current->no_new_privs) + return -EPERM; + /* released below */ cred = get_current_cred(); cxt = cred->security; @@ -754,6 +773,18 @@ int aa_change_profile(const char *ns_name, const char *hname, bool onexec, cxt = cred->security; profile = aa_cred_profile(cred); + /* + * Fail explicitly requested domain transitions if no_new_privs + * and not unconfined. + * Domain transitions from unconfined are allowed even when + * no_new_privs is set because this aways results in a reduction + * of permissions. + */ + if (current->no_new_privs && !unconfined(profile)) { + put_cred(cred); + return -EPERM; + } + if (ns_name) { /* released below */ ns = aa_find_namespace(profile->ns, ns_name); -- GitLab