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/chacha.h | 102 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 include/crypto/chacha.h (limited to 'include/crypto/chacha.h') diff --git a/include/crypto/chacha.h b/include/crypto/chacha.h new file mode 100644 index 000000000..1cc301a48 --- /dev/null +++ b/include/crypto/chacha.h @@ -0,0 +1,102 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Common values and helper functions for the ChaCha and XChaCha stream ciphers. + * + * XChaCha extends ChaCha's nonce to 192 bits, while provably retaining ChaCha's + * security. Here they share the same key size, tfm context, and setkey + * function; only their IV size and encrypt/decrypt function differ. + * + * The ChaCha paper specifies 20, 12, and 8-round variants. In general, it is + * recommended to use the 20-round variant ChaCha20. However, the other + * variants can be needed in some performance-sensitive scenarios. The generic + * ChaCha code currently allows only the 20 and 12-round variants. + */ + +#ifndef _CRYPTO_CHACHA_H +#define _CRYPTO_CHACHA_H + +#include +#include +#include + +/* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */ +#define CHACHA_IV_SIZE 16 + +#define CHACHA_KEY_SIZE 32 +#define CHACHA_BLOCK_SIZE 64 +#define CHACHAPOLY_IV_SIZE 12 + +#define CHACHA_KEY_WORDS 8 +#define CHACHA_STATE_WORDS 16 +#define HCHACHA_OUT_WORDS 8 + +/* 192-bit nonce, then 64-bit stream position */ +#define XCHACHA_IV_SIZE 32 + +struct chacha_state { + u32 x[CHACHA_STATE_WORDS]; +}; + +void chacha_block_generic(struct chacha_state *state, + u8 out[at_least CHACHA_BLOCK_SIZE], int nrounds); +static inline void chacha20_block(struct chacha_state *state, + u8 out[at_least CHACHA_BLOCK_SIZE]) +{ + chacha_block_generic(state, out, 20); +} + +void hchacha_block_generic(const struct chacha_state *state, + u32 out[at_least HCHACHA_OUT_WORDS], int nrounds); + +void hchacha_block(const struct chacha_state *state, + u32 out[at_least HCHACHA_OUT_WORDS], int nrounds); + +enum chacha_constants { /* expand 32-byte k */ + CHACHA_CONSTANT_EXPA = 0x61707865U, + CHACHA_CONSTANT_ND_3 = 0x3320646eU, + CHACHA_CONSTANT_2_BY = 0x79622d32U, + CHACHA_CONSTANT_TE_K = 0x6b206574U +}; + +static inline void chacha_init_consts(struct chacha_state *state) +{ + state->x[0] = CHACHA_CONSTANT_EXPA; + state->x[1] = CHACHA_CONSTANT_ND_3; + state->x[2] = CHACHA_CONSTANT_2_BY; + state->x[3] = CHACHA_CONSTANT_TE_K; +} + +static inline void chacha_init(struct chacha_state *state, + const u32 key[at_least CHACHA_KEY_WORDS], + const u8 iv[at_least CHACHA_IV_SIZE]) +{ + chacha_init_consts(state); + state->x[4] = key[0]; + state->x[5] = key[1]; + state->x[6] = key[2]; + state->x[7] = key[3]; + state->x[8] = key[4]; + state->x[9] = key[5]; + state->x[10] = key[6]; + state->x[11] = key[7]; + state->x[12] = get_unaligned_le32(iv + 0); + state->x[13] = get_unaligned_le32(iv + 4); + state->x[14] = get_unaligned_le32(iv + 8); + state->x[15] = get_unaligned_le32(iv + 12); +} + +void chacha_crypt(struct chacha_state *state, u8 *dst, const u8 *src, + unsigned int bytes, int nrounds); + +static inline void chacha20_crypt(struct chacha_state *state, + u8 *dst, const u8 *src, unsigned int bytes) +{ + chacha_crypt(state, dst, src, bytes, 20); +} + +static inline void chacha_zeroize_state(struct chacha_state *state) +{ + memzero_explicit(state, sizeof(*state)); +} + +#endif /* _CRYPTO_CHACHA_H */ -- cgit v1.3.1