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 --- include/crypto/xts.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 include/crypto/xts.h (limited to 'include/crypto/xts.h') diff --git a/include/crypto/xts.h b/include/crypto/xts.h new file mode 100644 index 000000000..16aef89f0 --- /dev/null +++ b/include/crypto/xts.h @@ -0,0 +1,50 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _CRYPTO_XTS_H +#define _CRYPTO_XTS_H + +#include +#include +#include + +#define XTS_BLOCK_SIZE 16 +#define XTS_FORBID_WEAK_KEYS (1 << 0) + +static inline int __xts_verify_key(const u8 *key, size_t keylen, int flags) +{ + /* + * key consists of keys of equal size concatenated, therefore + * the length must be even. + */ + if (keylen % 2) + return -EINVAL; + + /* + * In FIPS mode only a combined key length of either 256 or + * 512 bits is allowed, c.f. FIPS 140-3 IG C.I. + */ + if (fips_enabled && keylen != 32 && keylen != 64) + return -EINVAL; + + /* + * Ensure that the AES and tweak key are not identical when + * in FIPS mode or the FORBID_WEAK_KEYS flag is set. + */ + if ((fips_enabled || (flags & XTS_FORBID_WEAK_KEYS)) && + !crypto_memneq(key, key + (keylen / 2), keylen / 2)) + return -EINVAL; + + return 0; +} + +static inline int xts_verify_key(struct crypto_skcipher *tfm, const u8 *key, + unsigned int keylen) +{ + int flags = (crypto_skcipher_get_flags(tfm) & + CRYPTO_TFM_REQ_FORBID_WEAK_KEYS) ? + XTS_FORBID_WEAK_KEYS : + 0; + + return __xts_verify_key(key, keylen, flags); +} + +#endif /* _CRYPTO_XTS_H */ -- cgit v1.3.1