From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- security/apparmor/crypto.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 security/apparmor/crypto.c (limited to 'security/apparmor/crypto.c') diff --git a/security/apparmor/crypto.c b/security/apparmor/crypto.c new file mode 100644 index 000000000..d8a7bde94 --- /dev/null +++ b/security/apparmor/crypto.c @@ -0,0 +1,61 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AppArmor security module + * + * This file contains AppArmor policy loading interface function definitions. + * + * Copyright 2013 Canonical Ltd. + * + * Fns to provide a checksum of policy that has been loaded this can be + * compared to userspace policy compiles to check loaded policy is what + * it should be. + */ + +#include + +#include "include/apparmor.h" +#include "include/crypto.h" + +unsigned int aa_hash_size(void) +{ + return SHA256_DIGEST_SIZE; +} + +char *aa_calc_hash(void *data, size_t len) +{ + char *hash; + + hash = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); + if (!hash) + return ERR_PTR(-ENOMEM); + + sha256(data, len, hash); + return hash; +} + +int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start, + size_t len) +{ + struct sha256_ctx sctx; + __le32 le32_version = cpu_to_le32(version); + + if (!aa_g_hash_policy) + return 0; + + profile->hash = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); + if (!profile->hash) + return -ENOMEM; + + sha256_init(&sctx); + sha256_update(&sctx, (u8 *)&le32_version, 4); + sha256_update(&sctx, (u8 *)start, len); + sha256_final(&sctx, profile->hash); + return 0; +} + +int __init init_profile_hash(void) +{ + if (apparmor_initialized) + aa_info_message("AppArmor sha256 policy hashing enabled"); + return 0; +} -- cgit v1.3.1