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 --- crypto/cipher.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 crypto/cipher.c (limited to 'crypto/cipher.c') diff --git a/crypto/cipher.c b/crypto/cipher.c new file mode 100644 index 000000000..c9dab656a --- /dev/null +++ b/crypto/cipher.c @@ -0,0 +1,91 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cryptographic API. + * + * Single-block cipher operations. + * + * Copyright (c) 2002 James Morris + * Copyright (c) 2005 Herbert Xu + */ + +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +static int setkey_unaligned(struct crypto_cipher *tfm, const u8 *key, + unsigned int keylen) +{ + struct cipher_alg *cia = crypto_cipher_alg(tfm); + unsigned long alignmask = crypto_cipher_alignmask(tfm); + int ret; + u8 *buffer, *alignbuffer; + unsigned long absize; + + absize = keylen + alignmask; + buffer = kmalloc(absize, GFP_ATOMIC); + if (!buffer) + return -ENOMEM; + + alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); + memcpy(alignbuffer, key, keylen); + ret = cia->cia_setkey(crypto_cipher_tfm(tfm), alignbuffer, keylen); + kfree_sensitive(buffer); + return ret; + +} + +int crypto_cipher_setkey(struct crypto_cipher *tfm, + const u8 *key, unsigned int keylen) +{ + struct cipher_alg *cia = crypto_cipher_alg(tfm); + unsigned long alignmask = crypto_cipher_alignmask(tfm); + + if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) + return -EINVAL; + + if ((unsigned long)key & alignmask) + return setkey_unaligned(tfm, key, keylen); + + return cia->cia_setkey(crypto_cipher_tfm(tfm), key, keylen); +} +EXPORT_SYMBOL_NS_GPL(crypto_cipher_setkey, "CRYPTO_INTERNAL"); + +static inline void cipher_crypt_one(struct crypto_cipher *tfm, + u8 *dst, const u8 *src, bool enc) +{ + unsigned long alignmask = crypto_cipher_alignmask(tfm); + struct cipher_alg *cia = crypto_cipher_alg(tfm); + void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = + enc ? cia->cia_encrypt : cia->cia_decrypt; + + if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) { + unsigned int bs = crypto_cipher_blocksize(tfm); + u8 buffer[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK]; + u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); + + memcpy(tmp, src, bs); + fn(crypto_cipher_tfm(tfm), tmp, tmp); + memcpy(dst, tmp, bs); + } else { + fn(crypto_cipher_tfm(tfm), dst, src); + } +} + +void crypto_cipher_encrypt_one(struct crypto_cipher *tfm, + u8 *dst, const u8 *src) +{ + cipher_crypt_one(tfm, dst, src, true); +} +EXPORT_SYMBOL_NS_GPL(crypto_cipher_encrypt_one, "CRYPTO_INTERNAL"); + +void crypto_cipher_decrypt_one(struct crypto_cipher *tfm, + u8 *dst, const u8 *src) +{ + cipher_crypt_one(tfm, dst, src, false); +} +EXPORT_SYMBOL_NS_GPL(crypto_cipher_decrypt_one, "CRYPTO_INTERNAL"); -- cgit v1.3.1