From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="g8ApDjfS" Received: from out-173.mta0.migadu.com (out-173.mta0.migadu.com [IPv6:2001:41d0:1004:224b::ad]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7374EF4 for ; Fri, 1 Dec 2023 17:48:22 -0800 (PST) Message-ID: <3bea70d0-94a5-4d41-be15-2e8b5932a3b0@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1701481697; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8KTyotuJ0iVaM/ZGEo4sfOZrGm4bn2lECoBznZWD3BQ=; b=g8ApDjfS+nRH3NaAFuTeqM/8YnJUUQ7RwGFu8JLyyhS4+QwbkFdZYURN3ynbyu7MIDAngK t6IG+JNVLUW0wzHuB8tkZBeE2pubo+m6ieLtgMTHlRYAYmEU9BxKPZsGoQh8lbVNR4Lew4 XG4j+qBZ6JlqnLVSrHDlC9xezvCyoYM= Date: Fri, 1 Dec 2023 17:48:11 -0800 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v7 1/3] bpf: make common crypto API for TC/XDP programs Content-Language: en-US To: Vadim Fedorenko Cc: netdev@vger.kernel.org, linux-crypto@vger.kernel.org, bpf@vger.kernel.org, Vadim Fedorenko , Jakub Kicinski , Andrii Nakryiko , Alexei Starovoitov , Mykola Lysenko , Herbert Xu References: <20231202010604.1877561-1-vadfed@meta.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20231202010604.1877561-1-vadfed@meta.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 12/1/23 5:06 PM, Vadim Fedorenko wrote: > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index eb447b0a9423..0143ff6c93a1 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -1228,6 +1228,7 @@ int bpf_dynptr_check_size(u32 size); > u32 __bpf_dynptr_size(const struct bpf_dynptr_kern *ptr); > const void *__bpf_dynptr_data(const struct bpf_dynptr_kern *ptr, u32 len); > void *__bpf_dynptr_data_rw(const struct bpf_dynptr_kern *ptr, u32 len); > +bool __bpf_dynptr_is_rdonly(const struct bpf_dynptr_kern *ptr); > > #ifdef CONFIG_BPF_JIT > int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr); > diff --git a/include/linux/bpf_crypto.h b/include/linux/bpf_crypto.h > new file mode 100644 > index 000000000000..e81bd8ab979c > --- /dev/null > +++ b/include/linux/bpf_crypto.h > @@ -0,0 +1,23 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */ > +#ifndef _BPF_CRYPTO_H > +#define _BPF_CRYPTO_H > + > +struct bpf_crypto_type { > + void *(*alloc_tfm)(const char *algo); > + void (*free_tfm)(void *tfm); > + int (*has_algo)(const char *algo); > + int (*setkey)(void *tfm, const u8 *key, unsigned int keylen); > + int (*setauthsize)(void *tfm, unsigned int authsize); > + int (*encrypt)(void *tfm, const u8 *src, u8 *dst, unsigned int len, u8 *iv); > + int (*decrypt)(void *tfm, const u8 *src, u8 *dst, unsigned int len, u8 *iv); > + unsigned int (*ivsize)(void *tfm); > + u32 (*get_flags)(void *tfm); > + struct module *owner; > + char name[14]; Does it have a macro (from crypto ?) that can be reused here instead of a numeric constant? > +}; > + > +int bpf_crypto_register_type(const struct bpf_crypto_type *type); > +int bpf_crypto_unregister_type(const struct bpf_crypto_type *type); > + > +#endif /* _BPF_CRYPTO_H */ > diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile > index f526b7573e97..bcde762bb2c2 100644 > --- a/kernel/bpf/Makefile > +++ b/kernel/bpf/Makefile > @@ -41,6 +41,9 @@ obj-$(CONFIG_BPF_SYSCALL) += bpf_struct_ops.o > obj-$(CONFIG_BPF_SYSCALL) += cpumask.o > obj-${CONFIG_BPF_LSM} += bpf_lsm.o > endif > +ifeq ($(CONFIG_CRYPTO),y) > +obj-$(CONFIG_BPF_SYSCALL) += crypto.o > +endif > obj-$(CONFIG_BPF_PRELOAD) += preload/ > > obj-$(CONFIG_BPF_SYSCALL) += relo_core.o > diff --git a/kernel/bpf/crypto.c b/kernel/bpf/crypto.c > new file mode 100644 > index 000000000000..a1e543d1d7fe > --- /dev/null > +++ b/kernel/bpf/crypto.c > @@ -0,0 +1,364 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* Copyright (c) 2023 Meta, Inc */ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct bpf_crypto_type_list { > + const struct bpf_crypto_type *type; > + struct list_head list; > +}; > + > +static LIST_HEAD(bpf_crypto_types); > +static DECLARE_RWSEM(bpf_crypto_types_sem); > + > +/** > + * struct bpf_crypto_ctx - refcounted BPF crypto context structure > + * @type: The pointer to bpf crypto type > + * @tfm: The pointer to instance of crypto API struct. > + * @rcu: The RCU head used to free the crypto context with RCU safety. > + * @usage: Object reference counter. When the refcount goes to 0, the > + * memory is released back to the BPF allocator, which provides > + * RCU safety. > + */ > +struct bpf_crypto_ctx { > + const struct bpf_crypto_type *type; > + void *tfm; > + struct rcu_head rcu; > + refcount_t usage; > +}; > + > +int bpf_crypto_register_type(const struct bpf_crypto_type *type) > +{ > + struct bpf_crypto_type_list *node; > + int err = -EEXIST; > + > + down_write(&bpf_crypto_types_sem); > + list_for_each_entry(node, &bpf_crypto_types, list) { > + if (!strcmp(node->type->name, type->name)) > + goto unlock; > + } > + > + node = kmalloc(sizeof(*node), GFP_KERNEL); > + err = -ENOMEM; > + if (!node) > + goto unlock; > + > + node->type = type; > + list_add(&node->list, &bpf_crypto_types); > + err = 0; > + > +unlock: > + up_write(&bpf_crypto_types_sem); > + > + return err; > +} > +EXPORT_SYMBOL_GPL(bpf_crypto_register_type); > + > +int bpf_crypto_unregister_type(const struct bpf_crypto_type *type) > +{ > + struct bpf_crypto_type_list *node; > + int err = -ENOENT; > + > + down_write(&bpf_crypto_types_sem); > + list_for_each_entry(node, &bpf_crypto_types, list) { > + if (strcmp(node->type->name, type->name)) > + continue; > + > + list_del(&node->list); > + kfree(node); > + err = 0; > + break; > + } > + up_write(&bpf_crypto_types_sem); > + > + return err; > +} > +EXPORT_SYMBOL_GPL(bpf_crypto_unregister_type); > + > +static const struct bpf_crypto_type *bpf_crypto_get_type(const char *name) > +{ > + const struct bpf_crypto_type *type = ERR_PTR(-ENOENT); > + struct bpf_crypto_type_list *node; > + > + down_read(&bpf_crypto_types_sem); > + list_for_each_entry(node, &bpf_crypto_types, list) { > + if (strcmp(node->type->name, name)) > + continue; > + > + if (try_module_get(node->type->owner)) If I read patch 2 correctly, it is always built-in. I am not sure I understand the module_put/get in this patch. > + type = node->type; > + break; > + } > + up_read(&bpf_crypto_types_sem); > + > + return type; > +} > + > +__bpf_kfunc_start_defs(); > + > +/** > + * bpf_crypto_ctx_create() - Create a mutable BPF crypto context. > + * > + * Allocates a crypto context that can be used, acquired, and released by > + * a BPF program. The crypto context returned by this function must either > + * be embedded in a map as a kptr, or freed with bpf_crypto_ctx_release(). > + * As crypto API functions use GFP_KERNEL allocations, this function can > + * only be used in sleepable BPF programs. > + * > + * bpf_crypto_ctx_create() allocates memory for crypto context. > + * It may return NULL if no memory is available. > + * @type__str: pointer to string representation of crypto type. > + * @algo__str: pointer to string representation of algorithm. > + * @pkey: bpf_dynptr which holds cipher key to do crypto. > + * @err: integer to store error code when NULL is returned > + */ > +__bpf_kfunc struct bpf_crypto_ctx * > +bpf_crypto_ctx_create(const char *type__str, const char *algo__str, > + const struct bpf_dynptr_kern *pkey, > + unsigned int authsize, int *err) > +{ > + const struct bpf_crypto_type *type = bpf_crypto_get_type(type__str); > + struct bpf_crypto_ctx *ctx; > + const u8 *key; > + u32 key_len; > + > + type = bpf_crypto_get_type(type__str); > + if (IS_ERR(type)) { > + *err = PTR_ERR(type); > + return NULL; > + } > + > + if (!type->has_algo(algo__str)) { > + *err = -EOPNOTSUPP; > + goto err; ctx is still not initialized. The error path will crash. > + } > + > + if (!authsize && type->setauthsize) { > + *err = -EOPNOTSUPP; > + goto err; > + } > + > + if (authsize && !type->setauthsize) { > + *err = -EOPNOTSUPP; > + goto err; > + } > + > + key_len = __bpf_dynptr_size(pkey); > + if (!key_len) { > + *err = -EINVAL; > + goto err; > + } > + key = __bpf_dynptr_data(pkey, key_len); > + if (!key) { > + *err = -EINVAL; > + goto err; > + } > + > + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); > + if (!ctx) { > + *err = -ENOMEM; > + goto err; > + } > + > + ctx->type = type; > + ctx->tfm = type->alloc_tfm(algo__str); > + if (IS_ERR(ctx->tfm)) { > + *err = PTR_ERR(ctx->tfm); > + ctx->tfm = NULL; > + goto err; > + } > + > + if (authsize) { > + *err = type->setauthsize(ctx->tfm, authsize); > + if (*err) > + goto err; > + } > + > + *err = type->setkey(ctx->tfm, key, key_len); > + if (*err) > + goto err; > + > + refcount_set(&ctx->usage, 1); > + > + return ctx; > +err: > + if (ctx->tfm) > + type->free_tfm(ctx->tfm); > + kfree(ctx); > + module_put(type->owner); > + > + return NULL; > +} > + > +static void crypto_free_cb(struct rcu_head *head) > +{ > + struct bpf_crypto_ctx *ctx; > + > + ctx = container_of(head, struct bpf_crypto_ctx, rcu); > + ctx->type->free_tfm(ctx->tfm); > + module_put(ctx->type->owner); > + kfree(ctx); > +} > + > +/** > + * bpf_crypto_ctx_acquire() - Acquire a reference to a BPF crypto context. > + * @ctx: The BPF crypto context being acquired. The ctx must be a trusted > + * pointer. > + * > + * Acquires a reference to a BPF crypto context. The context returned by this function > + * must either be embedded in a map as a kptr, or freed with > + * bpf_crypto_skcipher_ctx_release(). > + */ > +__bpf_kfunc struct bpf_crypto_ctx * > +bpf_crypto_ctx_acquire(struct bpf_crypto_ctx *ctx) > +{ > + refcount_inc(&ctx->usage); > + return ctx; > +} > + > +/** > + * bpf_crypto_ctx_release() - Release a previously acquired BPF crypto context. > + * @ctx: The crypto context being released. > + * > + * Releases a previously acquired reference to a BPF crypto context. When the final > + * reference of the BPF crypto context has been released, it is subsequently freed in > + * an RCU callback in the BPF memory allocator. > + */ > +__bpf_kfunc void bpf_crypto_ctx_release(struct bpf_crypto_ctx *ctx) > +{ > + if (refcount_dec_and_test(&ctx->usage)) > + call_rcu(&ctx->rcu, crypto_free_cb); > +} > + > +static int bpf_crypto_crypt(const struct bpf_crypto_ctx *ctx, > + const struct bpf_dynptr_kern *src, > + struct bpf_dynptr_kern *dst, > + const struct bpf_dynptr_kern *iv, > + bool decrypt) > +{ > + u32 src_len, dst_len, iv_len; > + const u8 *psrc; > + u8 *pdst, *piv; > + int err; > + > + if (ctx->type->get_flags(ctx->tfm) & CRYPTO_TFM_NEED_KEY) > + return -EINVAL; > + > + if (__bpf_dynptr_is_rdonly(dst)) > + return -EINVAL; > + > + iv_len = __bpf_dynptr_size(iv); > + src_len = __bpf_dynptr_size(src); > + dst_len = __bpf_dynptr_size(dst); > + if (!src_len || !dst_len) > + return -EINVAL; > + > + if (iv_len != ctx->type->ivsize(ctx->tfm)) > + return -EINVAL; > + > + psrc = __bpf_dynptr_data(src, src_len); > + if (!psrc) > + return -EINVAL; > + pdst = __bpf_dynptr_data_rw(dst, dst_len); > + if (!pdst) > + return -EINVAL; > + > + piv = iv_len ? __bpf_dynptr_data_rw(iv, iv_len) : NULL; > + if (iv_len && !piv) > + return -EINVAL; > + > + err = decrypt ? ctx->type->decrypt(ctx->tfm, psrc, pdst, src_len, piv) > + : ctx->type->encrypt(ctx->tfm, psrc, pdst, src_len, piv); > + > + return err; > +} > + > +/** > + * bpf_crypto_decrypt() - Decrypt buffer using configured context and IV provided. > + * @ctx: The crypto context being used. The ctx must be a trusted pointer. > + * @src: bpf_dynptr to the encrypted data. Must be a trusted pointer. > + * @dst: bpf_dynptr to the buffer where to store the result. Must be a trusted pointer. > + * @iv: bpf_dynptr to IV data to be used by decryptor. > + * > + * Decrypts provided buffer using IV data and the crypto context. Crypto context must be configured. > + */ > +__bpf_kfunc int bpf_crypto_decrypt(struct bpf_crypto_ctx *ctx, > + const struct bpf_dynptr_kern *src, > + struct bpf_dynptr_kern *dst, > + struct bpf_dynptr_kern *iv) > +{ > + return bpf_crypto_crypt(ctx, src, dst, iv, true); > +} > + > +/** > + * bpf_crypto_encrypt() - Encrypt buffer using configured context and IV provided. > + * @ctx: The crypto context being used. The ctx must be a trusted pointer. > + * @src: bpf_dynptr to the plain data. Must be a trusted pointer. > + * @dst: bpf_dynptr to buffer where to store the result. Must be a trusted pointer. > + * @iv: bpf_dynptr to IV data to be used by decryptor. > + * > + * Encrypts provided buffer using IV data and the crypto context. Crypto context must be configured. > + */ > +__bpf_kfunc int bpf_crypto_encrypt(struct bpf_crypto_ctx *ctx, > + const struct bpf_dynptr_kern *src, > + struct bpf_dynptr_kern *dst, > + struct bpf_dynptr_kern *iv) > +{ > + return bpf_crypto_crypt(ctx, src, dst, iv, false); > +} > + > +__bpf_kfunc_end_defs(); > + > +BTF_SET8_START(crypt_init_kfunc_btf_ids) > +BTF_ID_FLAGS(func, bpf_crypto_ctx_create, KF_ACQUIRE | KF_RET_NULL | KF_SLEEPABLE) > +BTF_ID_FLAGS(func, bpf_crypto_ctx_release, KF_RELEASE) > +BTF_ID_FLAGS(func, bpf_crypto_ctx_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS) Considering bpf_crypto_ctx is rcu protected, the acquire may use "KF_ACQUIRE | KF_RCU | KF_RET_NULL" such that the bpf_crypto_ctx_acquire(ctx_from_map_value) will work and the user will prepare checking NULL from day one. > +BTF_SET8_END(crypt_init_kfunc_btf_ids) > + > +static const struct btf_kfunc_id_set crypt_init_kfunc_set = { > + .owner = THIS_MODULE, > + .set = &crypt_init_kfunc_btf_ids, > +}; > + > +BTF_SET8_START(crypt_kfunc_btf_ids) > +BTF_ID_FLAGS(func, bpf_crypto_decrypt, KF_RCU) > +BTF_ID_FLAGS(func, bpf_crypto_encrypt, KF_RCU) > +BTF_SET8_END(crypt_kfunc_btf_ids) > + > +static const struct btf_kfunc_id_set crypt_kfunc_set = { > + .owner = THIS_MODULE, > + .set = &crypt_kfunc_btf_ids, > +}; > + > +BTF_ID_LIST(bpf_crypto_dtor_ids) > +BTF_ID(struct, bpf_crypto_ctx) > +BTF_ID(func, bpf_crypto_ctx_release) > + > +static int __init crypto_kfunc_init(void) > +{ > + int ret; > + const struct btf_id_dtor_kfunc bpf_crypto_dtors[] = { > + { > + .btf_id = bpf_crypto_dtor_ids[0], > + .kfunc_btf_id = bpf_crypto_dtor_ids[1] > + }, > + }; > + > + ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &crypt_kfunc_set); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_ACT, &crypt_kfunc_set); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &crypt_kfunc_set); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, > + &crypt_init_kfunc_set); > + return ret ?: register_btf_id_dtor_kfuncs(bpf_crypto_dtors, > + ARRAY_SIZE(bpf_crypto_dtors), > + THIS_MODULE); > +} > + > +late_initcall(crypto_kfunc_init); > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > index b45a8381f9bd..b73314c0124e 100644 > --- a/kernel/bpf/helpers.c > +++ b/kernel/bpf/helpers.c > @@ -1436,7 +1436,7 @@ static const struct bpf_func_proto bpf_kptr_xchg_proto = { > #define DYNPTR_SIZE_MASK 0xFFFFFF > #define DYNPTR_RDONLY_BIT BIT(31) > > -static bool __bpf_dynptr_is_rdonly(const struct bpf_dynptr_kern *ptr) > +bool __bpf_dynptr_is_rdonly(const struct bpf_dynptr_kern *ptr) > { > return ptr->size & DYNPTR_RDONLY_BIT; > } > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index 8e7b6072e3f4..c54716966d5d 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -5162,6 +5162,7 @@ BTF_ID(struct, cgroup) > #endif > BTF_ID(struct, bpf_cpumask) > BTF_ID(struct, task_struct) > +BTF_ID(struct, bpf_crypto_ctx) > BTF_SET_END(rcu_protected_types) > > static bool rcu_protected_object(const struct btf *btf, u32 btf_id)