From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8C6DC131180 for ; Fri, 19 Apr 2024 18:57:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.185 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713553057; cv=none; b=M4B3PLoQAAwddiTj4AATafO47XkrwolKN7LX7VG9SB6zHdY9LNCu9M+uRkFza1vnOTOoNU46SMFiKx4zz1qfHGVItrJPVNVWr/RNMurYBAIpXTTDBdkGKH+6+NaUA7x96946KQgXPrJaaCXF6HdVZ1fmF8wWm3ChAzs9g2lSRFA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713553057; c=relaxed/simple; bh=C+Uu0Voqs0df1ulFjjPtHWbP4XxoAZiLPATcSsZ3b88=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=W0hljHdZsLW3iiP7H0z96+MMa2tWOjZJu8TtbANy8nJf7SQPFXNAA4ziYAZrbWCqihIJ963zMOclPSun0SQRwMgZB7E+UylwfINjRzvhevFm5ZUpjVO1Is7A2wc0taMBSDPnDy0oLvErOiWe9PVRMsu/PibB1SNe17W/bKbvJs8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ngfWeNMj; arc=none smtp.client-ip=91.218.175.185 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ngfWeNMj" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1713553052; 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=pQGF+clU8pqsfzPiMYxlEh6hNipiCLtIss6rESxKvlo=; b=ngfWeNMjkBhICP6WCxu7s01f4xzJ7jdENZIQQq5oKHqZb9fKj9an2jRscAQlzVz3n9gSrj UXgKgRa6kKqWG6Sw0QXaWTpgIjZJpeDUb+YrKAuGCc7Ioe5Ii1FB3T1kS8eMywf8kGcYJM qq/tNhq5kiCb/4cHkACB9pKJC3/wFGA= Date: Fri, 19 Apr 2024 11:57:24 -0700 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v9 1/4] bpf: make common crypto API for TC/XDP programs To: Vadim Fedorenko Cc: Vadim Fedorenko , Jakub Kicinski , Andrii Nakryiko , Alexei Starovoitov , Mykola Lysenko , Herbert Xu , netdev@vger.kernel.org, linux-crypto@vger.kernel.org, bpf@vger.kernel.org References: <20240416204004.3942393-1-vadfed@meta.com> <20240416204004.3942393-2-vadfed@meta.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau Content-Language: en-US In-Reply-To: <20240416204004.3942393-2-vadfed@meta.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 4/16/24 1:40 PM, Vadim Fedorenko wrote: > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index 5034c1b4ded7..acc479c13f52 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -1265,6 +1265,7 @@ 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..a41e71d4e2d9 > --- /dev/null > +++ b/include/linux/bpf_crypto.h > @@ -0,0 +1,24 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* Copyright (c) 2024 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); > + unsigned int (*statesize)(void *tfm); > + u32 (*get_flags)(void *tfm); > + struct module *owner; > + char name[14]; > +}; > + > +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 368c5d86b5b7..736bd22e5ce0 100644 > --- a/kernel/bpf/Makefile > +++ b/kernel/bpf/Makefile > @@ -44,6 +44,9 @@ 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..a76d80f37f55 > --- /dev/null > +++ b/kernel/bpf/crypto.c > @@ -0,0 +1,377 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* Copyright (c) 2024 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; > +}; > + > +/* BPF crypto initialization parameters struct */ > +/** > + * struct bpf_crypto_params - BPF crypto initialization parameters structure > + * @type: The string of crypto operation type. > + * @algo: The string of algorithm to initialize. > + * @key: The cipher key used to init crypto algorithm. > + * @key_len: The length of cipher key. > + * @authsize: The length of authentication tag used by algorithm. > + */ > +struct bpf_crypto_params { > + char type[14]; > + char algo[128]; > + __u8 key[256]; It should have a two byte hole here. Add __u8 reserved[2]; and check for 0 in bpf_crypto_ctx_create() in case it could be reused later. The bpf_crypto_ctx_create() should not be called very often. > + __u32 key_len; > + __u32 authsize; I don't think there is tail padding of this struct, so should be fine. > +} __attribute__((aligned(8))); Does it need aligned(8) here? > + > +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; > + u32 siv_len; > + 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)) > + 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. > + * @params: pointer to struct bpf_crypto_params which contains all the > + * details needed to initialise crypto context. > + * @err: integer to store error code when NULL is returned. > + */ > +__bpf_kfunc struct bpf_crypto_ctx * > +bpf_crypto_ctx_create(const struct bpf_crypto_params *params, int *err) Add a "u32 params__sz" arg in case that the params struct will have addition. Take a look at how opts__sz is checked in nf_conntrack_bpf.c. > +{ > + const struct bpf_crypto_type *type; > + struct bpf_crypto_ctx *ctx; > + > + type = bpf_crypto_get_type(params->type); > + if (IS_ERR(type)) { > + *err = PTR_ERR(type); > + return NULL; > + } > + > + if (!type->has_algo(params->algo)) { > + *err = -EOPNOTSUPP; > + goto err_module_put; > + } > + > + if (!params->authsize && type->setauthsize) { > + *err = -EOPNOTSUPP; > + goto err_module_put; > + } > + > + if (params->authsize && !type->setauthsize) { nit. Together with the previous "if" test, replace them with one test like: if (!!params->authsize ^ !!type->setauthsize) { > + *err = -EOPNOTSUPP; > + goto err_module_put; > + } > + > + if (!params->key_len) { Also checks "|| params->key_len > sizeof(params->key)" > + *err = -EINVAL; > + goto err_module_put; > + } > + > + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); > + if (!ctx) { > + *err = -ENOMEM; > + goto err_module_put; > + } > + > + ctx->type = type; > + ctx->tfm = type->alloc_tfm(params->algo); > + if (IS_ERR(ctx->tfm)) { > + *err = PTR_ERR(ctx->tfm); > + goto err_free_ctx; > + } > + > + if (params->authsize) { > + *err = type->setauthsize(ctx->tfm, params->authsize); > + if (*err) > + goto err_free_tfm; > + } > + > + *err = type->setkey(ctx->tfm, params->key, params->key_len); > + if (*err) > + goto err_free_tfm; > + > + if (type->get_flags(ctx->tfm) & CRYPTO_TFM_NEED_KEY) { > + *err = -EINVAL; > + goto err_free_tfm; > + } > + > + ctx->siv_len = type->ivsize(ctx->tfm) + type->statesize(ctx->tfm); > + > + refcount_set(&ctx->usage, 1); > + > + return ctx; > + > +err_free_tfm: > + type->free_tfm(ctx->tfm); > +err_free_ctx: > + kfree(ctx); > +err_module_put: > + 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) > +{ > + if (!refcount_inc_not_zero(&ctx->usage)) > + return NULL; > + 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 *siv, > + bool decrypt) > +{ > + u32 src_len, dst_len, siv_len; > + const u8 *psrc; > + u8 *pdst, *piv; > + int err; > + > + if (__bpf_dynptr_is_rdonly(dst)) > + return -EINVAL; > + > + siv_len = __bpf_dynptr_size(siv); > + src_len = __bpf_dynptr_size(src); > + dst_len = __bpf_dynptr_size(dst); > + if (!src_len || !dst_len) > + return -EINVAL; > + > + if (siv_len != ctx->siv_len) > + 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 = siv_len ? __bpf_dynptr_data_rw(siv, siv_len) : NULL; It has been a while. I don't remember if it has already been brought up before. The "const struct bpf_dynptr_kern *siv" here is essentially an optional pointer. Allowing NULL is a more intuitive usage instead of passing a 0-len dynptr. The verifier needs some changes to take __nullable suffix for "struct bpf_dynptr_kern *siv__nullable". This could be a follow up to relax the restriction to allow NULL and not necessary in this set. > + if (siv_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; > +}