From: John Johansen john.johansen@canonical.com
[ Upstream commit 3ed4aaa94fc07db3cd0c91be95e3e1b9782a2710 ]
The subset test is not taking into account the unconfined exception which will cause profile transitions in the stacked confinement case to fail when no_new_privs is applied.
This fixes a regression introduced in the fix for https://bugs.launchpad.net/bugs/1839037
BugLink: https://bugs.launchpad.net/bugs/1844186 Signed-off-by: John Johansen john.johansen@canonical.com Signed-off-by: Sasha Levin sashal@kernel.org --- security/apparmor/domain.c | 9 +++++---- security/apparmor/include/label.h | 1 + security/apparmor/label.c | 33 +++++++++++++++++++++++++++++++ 3 files changed, 39 insertions(+), 4 deletions(-)
diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c index 5dedc0173b024..1a33f490e6670 100644 --- a/security/apparmor/domain.c +++ b/security/apparmor/domain.c @@ -935,7 +935,8 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm) * aways results in a further reduction of permissions. */ if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && - !unconfined(label) && !aa_label_is_subset(new, ctx->nnp)) { + !unconfined(label) && + !aa_label_is_unconfined_subset(new, ctx->nnp)) { error = -EPERM; info = "no new privs"; goto audit; @@ -1213,7 +1214,7 @@ int aa_change_hat(const char *hats[], int count, u64 token, int flags) * reduce restrictions. */ if (task_no_new_privs(current) && !unconfined(label) && - !aa_label_is_subset(new, ctx->nnp)) { + !aa_label_is_unconfined_subset(new, ctx->nnp)) { /* not an apparmor denial per se, so don't log it */ AA_DEBUG("no_new_privs - change_hat denied"); error = -EPERM; @@ -1234,7 +1235,7 @@ int aa_change_hat(const char *hats[], int count, u64 token, int flags) * reduce restrictions. */ if (task_no_new_privs(current) && !unconfined(label) && - !aa_label_is_subset(previous, ctx->nnp)) { + !aa_label_is_unconfined_subset(previous, ctx->nnp)) { /* not an apparmor denial per se, so don't log it */ AA_DEBUG("no_new_privs - change_hat denied"); error = -EPERM; @@ -1429,7 +1430,7 @@ check: * reduce restrictions. */ if (task_no_new_privs(current) && !unconfined(label) && - !aa_label_is_subset(new, ctx->nnp)) { + !aa_label_is_unconfined_subset(new, ctx->nnp)) { /* not an apparmor denial per se, so don't log it */ AA_DEBUG("no_new_privs - change_hat denied"); error = -EPERM; diff --git a/security/apparmor/include/label.h b/security/apparmor/include/label.h index 47942c4ba7ca7..255764ab06e2f 100644 --- a/security/apparmor/include/label.h +++ b/security/apparmor/include/label.h @@ -281,6 +281,7 @@ bool aa_label_init(struct aa_label *label, int size, gfp_t gfp); struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub); +bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub); struct aa_profile *__aa_label_next_not_in_set(struct label_it *I, struct aa_label *set, struct aa_label *sub); diff --git a/security/apparmor/label.c b/security/apparmor/label.c index 6c3acae701efd..5f324d63ceaa3 100644 --- a/security/apparmor/label.c +++ b/security/apparmor/label.c @@ -550,6 +550,39 @@ bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub) return __aa_label_next_not_in_set(&i, set, sub) == NULL; }
+/** + * aa_label_is_unconfined_subset - test if @sub is a subset of @set + * @set: label to test against + * @sub: label to test if is subset of @set + * + * This checks for subset but taking into account unconfined. IF + * @sub contains an unconfined profile that does not have a matching + * unconfined in @set then this will not cause the test to fail. + * Conversely we don't care about an unconfined in @set that is not in + * @sub + * + * Returns: true if @sub is special_subset of @set + * else false + */ +bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub) +{ + struct label_it i = { }; + struct aa_profile *p; + + AA_BUG(!set); + AA_BUG(!sub); + + if (sub == set) + return true; + + do { + p = __aa_label_next_not_in_set(&i, set, sub); + if (p && !profile_unconfined(p)) + break; + } while (p); + + return p == NULL; +}
/**