[PATCH bpf-next 1/2] bpf: add skcipher API support to TC/XDP programs

[PATCH bpf-next 1/2] bpf: add skcipher API support to TC/XDP programs

[Vadim Fedorenko]

Add crypto API support to BPF to be able to decrypt or encrypt packets
in TC/XDP BPF programs. Only symmetric key ciphers are supported for
now. Special care should be taken for initialization part of crypto algo
because crypto_alloc_sync_skcipher() doesn't work with preemtion
disabled, it can be run only in sleepable BPF program. Also async crypto
is not supported because of the very same issue - TC/XDP BPF programs
are not sleepable.

Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
---
 include/linux/bpf.h   |   1 +
 kernel/bpf/Makefile   |   3 +
 kernel/bpf/crypto.c   | 278 ++++++++++++++++++++++++++++++++++++++++++
 kernel/bpf/helpers.c  |   2 +-
 kernel/bpf/verifier.c |   1 +
 5 files changed, 284 insertions(+), 1 deletion(-)
 create mode 100644 kernel/bpf/crypto.c

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d3c51a507508..17145738f176 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1222,6 +1222,7 @@ enum bpf_dynptr_type {
 
 int bpf_dynptr_check_size(u32 size);
 u32 __bpf_dynptr_size(const struct bpf_dynptr_kern *ptr);
+enum bpf_dynptr_type bpf_dynptr_get_type(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/kernel/bpf/Makefile b/kernel/bpf/Makefile
index f526b7573e97..e14b5834c477 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_SKCIPHER),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..f7803a5591b0
--- /dev/null
+++ b/kernel/bpf/crypto.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2023 Meta, Inc */
+#include <linux/bpf.h>
+#include <linux/bpf_mem_alloc.h>
+#include <linux/btf.h>
+#include <linux/btf_ids.h>
+#include <linux/filter.h>
+#include <linux/scatterlist.h>
+#include <linux/skbuff.h>
+#include <crypto/skcipher.h>
+
+/**
+ * struct bpf_crypto_skcipher_ctx - refcounted BPF sync skcipher context structure
+ * @tfm:	The pointer to crypto_sync_skcipher 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_skcipher_ctx {
+	struct crypto_sync_skcipher *tfm;
+	struct rcu_head rcu;
+	refcount_t usage;
+};
+
+static struct bpf_mem_alloc bpf_crypto_ctx_ma;
+
+__diag_push();
+__diag_ignore_all("-Wmissing-prototypes",
+		  "Global kfuncs as their definitions will be in BTF");
+
+/**
+ * bpf_crypto_skcipher_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_skcipher_ctx_release().
+ *
+ * bpf_crypto_skcipher_ctx_create() allocates memory using the BPF memory
+ * allocator, and will not block. It may return NULL if no memory is available.
+ * @algo: bpf_dynptr which holds string representation of algorithm.
+ * @key:  bpf_dynptr which holds cipher key to do crypto.
+ */
+__bpf_kfunc struct bpf_crypto_skcipher_ctx *
+bpf_crypto_skcipher_ctx_create(const struct bpf_dynptr_kern *algo, const struct bpf_dynptr_kern *key,
+			       int *err)
+{
+	struct bpf_crypto_skcipher_ctx *ctx;
+
+	if (__bpf_dynptr_size(algo) > CRYPTO_MAX_ALG_NAME) {
+		*err = -EINVAL;
+		return NULL;
+	}
+
+	if (!crypto_has_skcipher(algo->data, CRYPTO_ALG_TYPE_SKCIPHER, CRYPTO_ALG_TYPE_MASK)) {
+		*err = -EOPNOTSUPP;
+		return NULL;
+	}
+
+	ctx = bpf_mem_cache_alloc(&bpf_crypto_ctx_ma);
+	if (!ctx) {
+		*err = -ENOMEM;
+		return NULL;
+	}
+
+	memset(ctx, 0, sizeof(*ctx));
+
+	ctx->tfm = crypto_alloc_sync_skcipher(algo->data, 0, 0);
+	if (IS_ERR(ctx->tfm)) {
+		*err = PTR_ERR(ctx->tfm);
+		ctx->tfm = NULL;
+		goto err;
+	}
+
+	*err = crypto_sync_skcipher_setkey(ctx->tfm, key->data, __bpf_dynptr_size(key));
+	if (*err)
+		goto err;
+
+	refcount_set(&ctx->usage, 1);
+
+	return ctx;
+err:
+	if (ctx->tfm)
+		crypto_free_sync_skcipher(ctx->tfm);
+	bpf_mem_cache_free(&bpf_crypto_ctx_ma, ctx);
+
+	return NULL;
+}
+
+static void crypto_free_sync_skcipher_cb(struct rcu_head *head)
+{
+	struct bpf_crypto_skcipher_ctx *ctx;
+
+	ctx = container_of(head, struct bpf_crypto_skcipher_ctx, rcu);
+	crypto_free_sync_skcipher(ctx->tfm);
+	migrate_disable();
+	bpf_mem_cache_free(&bpf_crypto_ctx_ma, ctx);
+	migrate_enable();
+}
+
+/**
+ * bpf_crypto_skcipher_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_skcipher_ctx *
+bpf_crypto_skcipher_ctx_acquire(struct bpf_crypto_skcipher_ctx *ctx)
+{
+	refcount_inc(&ctx->usage);
+	return ctx;
+}
+
+/**
+ * bpf_crypto_skcipher_ctx_release() - Release a previously acquired BPF crypto context.
+ * @ctx: The crypto context being released.
+ *
+ * Releases a previously acquired reference to a BPF cpumask. When the final
+ * reference of the BPF cpumask has been released, it is subsequently freed in
+ * an RCU callback in the BPF memory allocator.
+ */
+__bpf_kfunc void bpf_crypto_skcipher_ctx_release(struct bpf_crypto_skcipher_ctx *ctx)
+{
+	if (refcount_dec_and_test(&ctx->usage))
+		call_rcu(&ctx->rcu, crypto_free_sync_skcipher_cb);
+}
+
+static void *__bpf_dynptr_data_ptr(const struct bpf_dynptr_kern *ptr)
+{
+	enum bpf_dynptr_type type;
+
+	if (!ptr->data)
+		return NULL;
+
+	type = bpf_dynptr_get_type(ptr);
+
+	switch (type) {
+	case BPF_DYNPTR_TYPE_LOCAL:
+	case BPF_DYNPTR_TYPE_RINGBUF:
+		return ptr->data + ptr->offset;
+	case BPF_DYNPTR_TYPE_SKB:
+		return skb_pointer_if_linear(ptr->data, ptr->offset, __bpf_dynptr_size(ptr));
+	case BPF_DYNPTR_TYPE_XDP:
+	{
+		void *xdp_ptr = bpf_xdp_pointer(ptr->data, ptr->offset, __bpf_dynptr_size(ptr));
+		if (!IS_ERR_OR_NULL(xdp_ptr))
+			return xdp_ptr;
+
+		return NULL;
+	}
+	default:
+		WARN_ONCE(true, "unknown dynptr type %d\n", type);
+		return NULL;
+	}
+}
+
+static int bpf_crypto_skcipher_crypt(struct crypto_sync_skcipher *tfm,
+				     const struct bpf_dynptr_kern *src,
+				     struct bpf_dynptr_kern *dst,
+				     const struct bpf_dynptr_kern *iv,
+				     bool decrypt)
+{
+	struct skcipher_request *req = NULL;
+	struct scatterlist sgin, sgout;
+	int err;
+
+	if (crypto_sync_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
+		return -EINVAL;
+
+	if (!__bpf_dynptr_size(dst) || !__bpf_dynptr_size(src))
+		return -EINVAL;
+
+	if (__bpf_dynptr_size(iv) != crypto_sync_skcipher_ivsize(tfm))
+		return -EINVAL;
+
+	req = skcipher_request_alloc(&tfm->base, GFP_ATOMIC);
+	if (!req)
+		return -ENOMEM;
+
+	sg_init_one(&sgin, __bpf_dynptr_data_ptr(src), __bpf_dynptr_size(src));
+	sg_init_one(&sgout, __bpf_dynptr_data_ptr(dst), __bpf_dynptr_size(dst));
+
+	skcipher_request_set_crypt(req, &sgin, &sgout, __bpf_dynptr_size(src),
+				   __bpf_dynptr_data_ptr(iv));
+
+	err = decrypt ? crypto_skcipher_decrypt(req) : crypto_skcipher_encrypt(req);
+
+	skcipher_request_free(req);
+
+	return err;
+}
+
+/**
+ * bpf_crypto_skcipher_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_skcipher_decrypt(struct bpf_crypto_skcipher_ctx *ctx,
+					    const struct bpf_dynptr_kern *src,
+					    struct bpf_dynptr_kern *dst,
+					    const struct bpf_dynptr_kern *iv)
+{
+	return bpf_crypto_skcipher_crypt(ctx->tfm, src, dst, iv, true);
+}
+
+/**
+ * bpf_crypto_skcipher_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_skcipher_encrypt(struct bpf_crypto_skcipher_ctx *ctx,
+					    const struct bpf_dynptr_kern *src,
+					    struct bpf_dynptr_kern *dst,
+					    const struct bpf_dynptr_kern *iv)
+{
+	return bpf_crypto_skcipher_crypt(ctx->tfm, src, dst, iv, false);
+}
+
+__diag_pop();
+
+BTF_SET8_START(crypt_skcipher_init_kfunc_btf_ids)
+BTF_ID_FLAGS(func, bpf_crypto_skcipher_ctx_create, KF_ACQUIRE | KF_RET_NULL | KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_crypto_skcipher_ctx_release, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_crypto_skcipher_ctx_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
+BTF_SET8_END(crypt_skcipher_init_kfunc_btf_ids)
+
+static const struct btf_kfunc_id_set crypt_skcipher_init_kfunc_set = {
+	.owner = THIS_MODULE,
+	.set   = &crypt_skcipher_init_kfunc_btf_ids,
+};
+
+BTF_SET8_START(crypt_skcipher_kfunc_btf_ids)
+BTF_ID_FLAGS(func, bpf_crypto_skcipher_decrypt, KF_RCU)
+BTF_ID_FLAGS(func, bpf_crypto_skcipher_encrypt, KF_RCU)
+BTF_SET8_END(crypt_skcipher_kfunc_btf_ids)
+
+static const struct btf_kfunc_id_set crypt_skcipher_kfunc_set = {
+	.owner = THIS_MODULE,
+	.set   = &crypt_skcipher_kfunc_btf_ids,
+};
+
+BTF_ID_LIST(crypto_skcipher_dtor_ids)
+BTF_ID(struct, bpf_crypto_skcipher_ctx)
+BTF_ID(func, bpf_crypto_skcipher_ctx_release)
+
+static int __init crypto_skcipher_kfunc_init(void)
+{
+	int ret;
+	const struct btf_id_dtor_kfunc crypto_skcipher_dtors[] = {
+		{
+			.btf_id	      = crypto_skcipher_dtor_ids[0],
+			.kfunc_btf_id = crypto_skcipher_dtor_ids[1]
+		},
+	};
+
+	ret = bpf_mem_alloc_init(&bpf_crypto_ctx_ma, sizeof(struct bpf_crypto_skcipher_ctx), false);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &crypt_skcipher_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_ACT, &crypt_skcipher_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &crypt_skcipher_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &crypt_skcipher_init_kfunc_set);
+	return  ret ?: register_btf_id_dtor_kfuncs(crypto_skcipher_dtors,
+						   ARRAY_SIZE(crypto_skcipher_dtors),
+						   THIS_MODULE);
+}
+
+late_initcall(crypto_skcipher_kfunc_init);
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 62a53ebfedf9..0c2a10ff5dfd 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1444,7 +1444,7 @@ static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_typ
 	ptr->size |= type << DYNPTR_TYPE_SHIFT;
 }
 
-static enum bpf_dynptr_type bpf_dynptr_get_type(const struct bpf_dynptr_kern *ptr)
+enum bpf_dynptr_type bpf_dynptr_get_type(const struct bpf_dynptr_kern *ptr)
 {
 	return (ptr->size & ~(DYNPTR_RDONLY_BIT)) >> DYNPTR_TYPE_SHIFT;
 }
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index bb58987e4844..75d2f47ca3cb 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5184,6 +5184,7 @@ BTF_ID(struct, prog_test_ref_kfunc)
 BTF_ID(struct, cgroup)
 BTF_ID(struct, bpf_cpumask)
 BTF_ID(struct, task_struct)
+BTF_ID(struct, bpf_crypto_skcipher_ctx)
 BTF_SET_END(rcu_protected_types)
 
 static bool rcu_protected_object(const struct btf *btf, u32 btf_id)
-- 
2.39.3

[PATCH bpf-next 2/2] selftests: bpf: crypto skcipher algo selftests

[Vadim Fedorenko]

Add simple tc hook selftests to show the way to work with new crypto
BPF API. Some weird structre and map are added to setup program to make
verifier happy about dynptr initialization from memory. Simple AES-ECB
algo is used to demonstrate encryption and decryption of fixed size
buffers.

Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
---
 tools/testing/selftests/bpf/config            |   1 +
 .../selftests/bpf/prog_tests/crypto_sanity.c  | 129 +++++++++++++++
 .../selftests/bpf/progs/crypto_common.h       |  98 +++++++++++
 .../selftests/bpf/progs/crypto_sanity.c       | 154 ++++++++++++++++++
 4 files changed, 382 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/crypto_sanity.c
 create mode 100644 tools/testing/selftests/bpf/progs/crypto_common.h
 create mode 100644 tools/testing/selftests/bpf/progs/crypto_sanity.c

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 02dd4409200e..2a5d6339831b 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -14,6 +14,7 @@ CONFIG_CGROUP_BPF=y
 CONFIG_CRYPTO_HMAC=y
 CONFIG_CRYPTO_SHA256=y
 CONFIG_CRYPTO_USER_API_HASH=y
+CONFIG_CRYPTO_SKCIPHER=y
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_INFO_BTF=y
 CONFIG_DEBUG_INFO_DWARF4=y
diff --git a/tools/testing/selftests/bpf/prog_tests/crypto_sanity.c b/tools/testing/selftests/bpf/prog_tests/crypto_sanity.c
new file mode 100644
index 000000000000..a43969da6d15
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/crypto_sanity.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <net/if.h>
+#include <linux/in6.h>
+
+#include "test_progs.h"
+#include "network_helpers.h"
+#include "crypto_sanity.skel.h"
+
+#define NS_TEST "crypto_sanity_ns"
+#define IPV6_IFACE_ADDR "face::1"
+#define UDP_TEST_PORT 7777
+static const char plain_text[] = "stringtoencrypt0";
+static const char crypted_data[] = "\x5B\x59\x39\xEA\xD9\x7A\x2D\xAD\xA7\xE0\x43" \
+				   "\x37\x8A\x77\x17\xB2";
+
+void test_crypto_sanity(void)
+{
+	LIBBPF_OPTS(bpf_tc_hook, qdisc_hook, .attach_point = BPF_TC_EGRESS);
+	LIBBPF_OPTS(bpf_tc_opts, tc_attach_enc);
+	LIBBPF_OPTS(bpf_tc_opts, tc_attach_dec);
+	LIBBPF_OPTS(bpf_test_run_opts, opts,
+		    .data_in = crypted_data,
+		    .data_size_in = sizeof(crypted_data),
+		    .repeat = 1,
+	);
+	struct nstoken *nstoken = NULL;
+	struct crypto_sanity *skel;
+	struct sockaddr_in6 addr;
+	int sockfd, err, pfd;
+	socklen_t addrlen;
+
+	skel = crypto_sanity__open();
+	if (!ASSERT_OK_PTR(skel, "skel open"))
+		return;
+
+	bpf_program__set_autoload(skel->progs.skb_crypto_setup, true);
+
+	SYS(fail, "ip netns add %s", NS_TEST);
+	SYS(fail, "ip -net %s -6 addr add %s/128 dev lo nodad", NS_TEST, IPV6_IFACE_ADDR);
+	SYS(fail, "ip -net %s link set dev lo up", NS_TEST);
+
+	err = crypto_sanity__load(skel);
+	if (!ASSERT_OK(err, "crypto_sanity__load"))
+		goto fail;
+
+	nstoken = open_netns(NS_TEST);
+	if (!ASSERT_OK_PTR(nstoken, "open_netns"))
+		goto fail;
+
+	qdisc_hook.ifindex = if_nametoindex("lo");
+	if (!ASSERT_GT(qdisc_hook.ifindex, 0, "if_nametoindex lo"))
+		goto fail;
+
+	err = crypto_sanity__attach(skel);
+	if (!ASSERT_OK(err, "crypto_sanity__attach"))
+		goto fail;
+
+	pfd = bpf_program__fd(skel->progs.skb_crypto_setup);
+	if (!ASSERT_GT(pfd, 0, "skb_crypto_setup fd"))
+		goto fail;
+
+	err = bpf_prog_test_run_opts(pfd, &opts);
+	if (!ASSERT_OK(err, "skb_crypto_setup") ||
+	    !ASSERT_OK(opts.retval, "skb_crypto_setup retval"))
+		goto fail;
+
+	if (!ASSERT_OK(skel->bss->status, "skb_crypto_setup status"))
+		goto fail;
+
+	err = bpf_tc_hook_create(&qdisc_hook);
+	if (!ASSERT_OK(err, "create qdisc hook"))
+		goto fail;
+
+	addrlen = sizeof(addr);
+	err = make_sockaddr(AF_INET6, IPV6_IFACE_ADDR, UDP_TEST_PORT,
+			    (void *)&addr, &addrlen);
+	if (!ASSERT_OK(err, "make_sockaddr"))
+		goto fail;
+
+	tc_attach_dec.prog_fd = bpf_program__fd(skel->progs.decrypt_sanity);
+	err = bpf_tc_attach(&qdisc_hook, &tc_attach_dec);
+	if (!ASSERT_OK(err, "attach decrypt filter"))
+		goto fail;
+
+	sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
+	if (!ASSERT_NEQ(sockfd, -1, "decrypt socket"))
+		goto fail;
+	err = sendto(sockfd, crypted_data, 16, 0, (void *)&addr, addrlen);
+	close(sockfd);
+	if (!ASSERT_EQ(err, 16, "decrypt send"))
+		goto fail;
+
+	bpf_tc_detach(&qdisc_hook, &tc_attach_dec);
+	if (!ASSERT_OK(skel->bss->status, "decrypt status"))
+		goto fail;
+	if (!ASSERT_STRNEQ(skel->bss->dst, plain_text, sizeof(plain_text), "decrypt"))
+		goto fail;
+
+	tc_attach_enc.prog_fd = bpf_program__fd(skel->progs.encrypt_sanity);
+	err = bpf_tc_attach(&qdisc_hook, &tc_attach_enc);
+	if (!ASSERT_OK(err, "attach encrypt filter"))
+		goto fail;
+
+	sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
+	if (!ASSERT_NEQ(sockfd, -1, "encrypt socket"))
+		goto fail;
+	err = sendto(sockfd, plain_text, 16, 0, (void *)&addr, addrlen);
+	close(sockfd);
+	if (!ASSERT_EQ(err, 16, "encrypt send"))
+		goto fail;
+
+	bpf_tc_detach(&qdisc_hook, &tc_attach_enc);
+	if (!ASSERT_OK(skel->bss->status, "encrypt status"))
+		goto fail;
+	if (!ASSERT_STRNEQ(skel->bss->dst, crypted_data, sizeof(crypted_data), "encrypt"))
+		goto fail;
+
+fail:
+	if (nstoken) {
+		bpf_tc_hook_destroy(&qdisc_hook);
+		close_netns(nstoken);
+	}
+	SYS_NOFAIL("ip netns del " NS_TEST " &> /dev/null");
+	crypto_sanity__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/crypto_common.h b/tools/testing/selftests/bpf/progs/crypto_common.h
new file mode 100644
index 000000000000..c448f07d6e42
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/crypto_common.h
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#ifndef _CRYPTO_COMMON_H
+#define _CRYPTO_COMMON_H
+
+#include "errno.h"
+#include <stdbool.h>
+
+#define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8)))
+private(CTX) static struct bpf_crypto_skcipher_ctx __kptr * global_crypto_ctx;
+
+struct bpf_crypto_skcipher_ctx *bpf_crypto_skcipher_ctx_create(const struct bpf_dynptr *algo, const struct bpf_dynptr *key, int *err) __ksym;
+struct bpf_crypto_skcipher_ctx *bpf_crypto_skcipher_ctx_acquire(struct bpf_crypto_skcipher_ctx *ctx) __ksym;
+void bpf_crypto_skcipher_ctx_release(struct bpf_crypto_skcipher_ctx *ctx) __ksym;
+int bpf_crypto_skcipher_encrypt(struct bpf_crypto_skcipher_ctx *ctx, const struct bpf_dynptr *src, struct bpf_dynptr *dst, const struct bpf_dynptr *iv) __ksym;
+int bpf_crypto_skcipher_decrypt(struct bpf_crypto_skcipher_ctx *ctx, const struct bpf_dynptr *src, struct bpf_dynptr *dst, const struct bpf_dynptr *iv) __ksym;
+
+struct __crypto_skcipher_ctx_value {
+	struct bpf_crypto_skcipher_ctx __kptr * ctx;
+};
+
+struct crypto_conf_value {
+	__u8 algo[32];
+	__u32 algo_size;
+	__u8 key[32];
+	__u32 key_size;
+	__u8 iv[32];
+	__u32 iv_size;
+	__u8 dst[32];
+	__u32 dst_size;
+};
+
+struct array_conf_map {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, int);
+	__type(value, struct crypto_conf_value);
+	__uint(max_entries, 1);
+} __crypto_conf_map SEC(".maps");
+
+struct array_map {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, int);
+	__type(value, struct __crypto_skcipher_ctx_value);
+	__uint(max_entries, 1);
+} __crypto_skcipher_ctx_map SEC(".maps");
+
+static inline struct crypto_conf_value *crypto_conf_lookup(void)
+{
+	struct crypto_conf_value *v, local = {};
+	u32 key = 0;
+
+	v = bpf_map_lookup_elem(&__crypto_conf_map, &key);
+	if (v)
+		return v;
+
+	bpf_map_update_elem(&__crypto_conf_map, &key, &local, 0);
+	return bpf_map_lookup_elem(&__crypto_conf_map, &key);
+}
+
+
+static inline struct __crypto_skcipher_ctx_value *crypto_skcipher_ctx_value_lookup(void)
+{
+	u32 key = 0;
+
+	return bpf_map_lookup_elem(&__crypto_skcipher_ctx_map, &key);
+}
+
+static inline int crypto_skcipher_ctx_insert(struct bpf_crypto_skcipher_ctx *ctx)
+{
+	struct __crypto_skcipher_ctx_value local, *v;
+	long status;
+	struct bpf_crypto_skcipher_ctx *old;
+	u32 key = 0;
+
+	local.ctx = NULL;
+	status = bpf_map_update_elem(&__crypto_skcipher_ctx_map, &key, &local, 0);
+	if (status) {
+		bpf_crypto_skcipher_ctx_release(ctx);
+		return status;
+	}
+
+	v = bpf_map_lookup_elem(&__crypto_skcipher_ctx_map, &key);
+	if (!v) {
+		bpf_crypto_skcipher_ctx_release(ctx);
+		return -ENOENT;
+	}
+
+	old = bpf_kptr_xchg(&v->ctx, ctx);
+	if (old) {
+		bpf_crypto_skcipher_ctx_release(old);
+		return -EEXIST;
+	}
+
+	return 0;
+}
+
+#endif /* _CRYPTO_COMMON_H */
diff --git a/tools/testing/selftests/bpf/progs/crypto_sanity.c b/tools/testing/selftests/bpf/progs/crypto_sanity.c
new file mode 100644
index 000000000000..71a172d8d2a2
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/crypto_sanity.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include "bpf_tracing_net.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_misc.h"
+#include "bpf_kfuncs.h"
+#include "crypto_common.h"
+
+#define UDP_TEST_PORT 7777
+unsigned char crypto_key[16] = "testtest12345678";
+char crypto_algo[9] = "ecb(aes)";
+char dst[32] = {};
+int status;
+
+static inline int skb_validate_test(const struct __sk_buff *skb)
+{
+	struct ipv6hdr ip6h;
+	struct udphdr udph;
+	u32 offset;
+
+	if (skb->protocol != __bpf_constant_htons(ETH_P_IPV6))
+		return -1;
+
+	if (bpf_skb_load_bytes(skb, ETH_HLEN, &ip6h, sizeof(ip6h)))
+		return -1;
+
+	if (ip6h.nexthdr != IPPROTO_UDP)
+		return -1;
+
+	if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(ip6h), &udph, sizeof(udph)))
+		return -1;
+
+	if (udph.dest != __bpf_constant_htons(UDP_TEST_PORT))
+		return -1;
+
+	offset = ETH_HLEN + sizeof(ip6h) + sizeof(udph);
+	if (skb->len < offset + 16)
+		return -1;
+
+	return offset;
+}
+
+SEC("?fentry.s/bpf_fentry_test1")
+int BPF_PROG(skb_crypto_setup)
+{
+	struct crypto_conf_value *c;
+	struct bpf_dynptr algo, key;
+	int err = 0;
+
+	status = 0;
+
+	c = crypto_conf_lookup();
+	if (!c) {
+		status = -EINVAL;
+		return 0;
+	}
+
+	bpf_dynptr_from_mem(crypto_algo, sizeof(crypto_algo), 0, &algo);
+	bpf_dynptr_from_mem(crypto_key, sizeof(crypto_key), 0, &key);
+	struct bpf_crypto_skcipher_ctx *cctx = bpf_crypto_skcipher_ctx_create(&algo, &key, &err);
+
+	if (!cctx) {
+		status = err;
+		return 0;
+	}
+
+	err = crypto_skcipher_ctx_insert(cctx);
+	if (err && err != -EEXIST)
+		status = err;
+
+	return 0;
+}
+
+SEC("tc")
+int decrypt_sanity(struct __sk_buff *skb)
+{
+	struct __crypto_skcipher_ctx_value *v;
+	struct bpf_crypto_skcipher_ctx *ctx;
+	struct bpf_dynptr psrc, pdst, iv;
+	int err;
+
+	err = skb_validate_test(skb);
+	if (err < 0) {
+		status = err;
+		return TC_ACT_SHOT;
+	}
+
+	v = crypto_skcipher_ctx_value_lookup();
+	if (!v) {
+		status = -ENOENT;
+		return TC_ACT_SHOT;
+	}
+
+	ctx = v->ctx;
+	if (!ctx) {
+		status = -ENOENT;
+		return TC_ACT_SHOT;
+	}
+
+	bpf_dynptr_from_skb(skb, 0, &psrc);
+	bpf_dynptr_adjust(&psrc, err, err + 16);
+	bpf_dynptr_from_mem(dst, sizeof(dst), 0, &pdst);
+	bpf_dynptr_from_mem(dst, 0, 0, &iv);
+
+	bpf_crypto_skcipher_decrypt(ctx, &psrc, &pdst, &iv);
+
+	status = 0;
+
+	return TC_ACT_SHOT;
+}
+
+SEC("tc")
+int encrypt_sanity(struct __sk_buff *skb)
+{
+	struct __crypto_skcipher_ctx_value *v;
+	struct bpf_crypto_skcipher_ctx *ctx;
+	struct bpf_dynptr psrc, pdst, iv;
+	int err;
+
+	status = 0;
+
+	err = skb_validate_test(skb);
+	if (err < 0) {
+		status = err;
+		return TC_ACT_SHOT;
+	}
+
+	v = crypto_skcipher_ctx_value_lookup();
+	if (!v) {
+		status = -ENOENT;
+		return TC_ACT_SHOT;
+	}
+
+	ctx = v->ctx;
+	if (!ctx) {
+		status = -ENOENT;
+		return TC_ACT_SHOT;
+	}
+
+	bpf_dynptr_from_skb(skb, 0, &psrc);
+	bpf_dynptr_adjust(&psrc, err, err + 16);
+	bpf_dynptr_from_mem(dst, sizeof(dst), 0, &pdst);
+	bpf_dynptr_from_mem(dst, 0, 0, &iv);
+
+	bpf_crypto_skcipher_encrypt(ctx, &psrc, &pdst, &iv);
+
+	return TC_ACT_SHOT;
+}
+
+char __license[] SEC("license") = "GPL";
-- 
2.39.3

Re: [PATCH bpf-next 2/2] selftests: bpf: crypto skcipher algo selftests

[Daniel Borkmann]

On 10/26/23 3:59 AM, Vadim Fedorenko wrote:
> Add simple tc hook selftests to show the way to work with new crypto
> BPF API. Some weird structre and map are added to setup program to make
> verifier happy about dynptr initialization from memory. Simple AES-ECB
> algo is used to demonstrate encryption and decryption of fixed size
> buffers.
> 
> Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
> ---
>   tools/testing/selftests/bpf/config            |   1 +
>   .../selftests/bpf/prog_tests/crypto_sanity.c  | 129 +++++++++++++++
>   .../selftests/bpf/progs/crypto_common.h       |  98 +++++++++++
>   .../selftests/bpf/progs/crypto_sanity.c       | 154 ++++++++++++++++++
>   4 files changed, 382 insertions(+)
>   create mode 100644 tools/testing/selftests/bpf/prog_tests/crypto_sanity.c
>   create mode 100644 tools/testing/selftests/bpf/progs/crypto_common.h
>   create mode 100644 tools/testing/selftests/bpf/progs/crypto_sanity.c
> 
> diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
> index 02dd4409200e..2a5d6339831b 100644
> --- a/tools/testing/selftests/bpf/config
> +++ b/tools/testing/selftests/bpf/config
> @@ -14,6 +14,7 @@ CONFIG_CGROUP_BPF=y
>   CONFIG_CRYPTO_HMAC=y
>   CONFIG_CRYPTO_SHA256=y
>   CONFIG_CRYPTO_USER_API_HASH=y
> +CONFIG_CRYPTO_SKCIPHER=y
>   CONFIG_DEBUG_INFO=y
>   CONFIG_DEBUG_INFO_BTF=y
>   CONFIG_DEBUG_INFO_DWARF4=y

Quick note: for upstream CI side, more config seems missing, see the GHA failure:

https://github.com/kernel-patches/bpf/actions/runs/6654055344/job/18081734522

Notice: Success: 435/3403, Skipped: 32, Failed: 1
Error: #64 crypto_sanity
   Error: #64 crypto_sanity
   test_crypto_sanity:PASS:skel open 0 nsec
   test_crypto_sanity:PASS:ip netns add crypto_sanity_ns 0 nsec
   test_crypto_sanity:PASS:ip -net crypto_sanity_ns -6 addr add face::1/128 dev lo nodad 0 nsec
   test_crypto_sanity:PASS:ip -net crypto_sanity_ns link set dev lo up 0 nsec
   test_crypto_sanity:PASS:crypto_sanity__load 0 nsec
   open_netns:PASS:malloc token 0 nsec
   open_netns:PASS:open /proc/self/ns/net 0 nsec
   open_netns:PASS:open netns fd 0 nsec
   open_netns:PASS:setns 0 nsec
   test_crypto_sanity:PASS:open_netns 0 nsec
   test_crypto_sanity:PASS:if_nametoindex lo 0 nsec
   test_crypto_sanity:PASS:crypto_sanity__attach 0 nsec
   test_crypto_sanity:PASS:skb_crypto_setup fd 0 nsec
   test_crypto_sanity:PASS:skb_crypto_setup 0 nsec
   test_crypto_sanity:PASS:skb_crypto_setup retval 0 nsec
   test_crypto_sanity:FAIL:skb_crypto_setup status unexpected error: -95 (errno 2)
   libbpf: Kernel error message: Parent Qdisc doesn't exists
   close_netns:PASS:setns 0 nsec
Test Results:
              bpftool: PASS
  test_progs-no_alu32: FAIL (returned 1)
             shutdown: CLEAN
Error: Process completed with exit code 1.

Re: [PATCH bpf-next 2/2] selftests: bpf: crypto skcipher algo selftests

[Vadim Fedorenko]

On 26/10/2023 15:02, Daniel Borkmann wrote:
> On 10/26/23 3:59 AM, Vadim Fedorenko wrote:
>> Add simple tc hook selftests to show the way to work with new crypto
>> BPF API. Some weird structre and map are added to setup program to make
>> verifier happy about dynptr initialization from memory. Simple AES-ECB
>> algo is used to demonstrate encryption and decryption of fixed size
>> buffers.
>>
>> Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
>> ---
>>   tools/testing/selftests/bpf/config            |   1 +
>>   .../selftests/bpf/prog_tests/crypto_sanity.c  | 129 +++++++++++++++
>>   .../selftests/bpf/progs/crypto_common.h       |  98 +++++++++++
>>   .../selftests/bpf/progs/crypto_sanity.c       | 154 ++++++++++++++++++
>>   4 files changed, 382 insertions(+)
>>   create mode 100644 
>> tools/testing/selftests/bpf/prog_tests/crypto_sanity.c
>>   create mode 100644 tools/testing/selftests/bpf/progs/crypto_common.h
>>   create mode 100644 tools/testing/selftests/bpf/progs/crypto_sanity.c
>>
>> diff --git a/tools/testing/selftests/bpf/config 
>> b/tools/testing/selftests/bpf/config
>> index 02dd4409200e..2a5d6339831b 100644
>> --- a/tools/testing/selftests/bpf/config
>> +++ b/tools/testing/selftests/bpf/config
>> @@ -14,6 +14,7 @@ CONFIG_CGROUP_BPF=y
>>   CONFIG_CRYPTO_HMAC=y
>>   CONFIG_CRYPTO_SHA256=y
>>   CONFIG_CRYPTO_USER_API_HASH=y
>> +CONFIG_CRYPTO_SKCIPHER=y
>>   CONFIG_DEBUG_INFO=y
>>   CONFIG_DEBUG_INFO_BTF=y
>>   CONFIG_DEBUG_INFO_DWARF4=y
> 
> Quick note: for upstream CI side, more config seems missing, see the GHA 
> failure:

Thanks for the signal, Daniel. Looks like CONFIG_CRYPTO_ECB is missing.
I'll adjust config for v2, but I'll wait a bit longer to get more
feedback

> https://github.com/kernel-patches/bpf/actions/runs/6654055344/job/18081734522
> 
> Notice: Success: 435/3403, Skipped: 32, Failed: 1
> Error: #64 crypto_sanity
>    Error: #64 crypto_sanity
>    test_crypto_sanity:PASS:skel open 0 nsec
>    test_crypto_sanity:PASS:ip netns add crypto_sanity_ns 0 nsec
>    test_crypto_sanity:PASS:ip -net crypto_sanity_ns -6 addr add 
> face::1/128 dev lo nodad 0 nsec
>    test_crypto_sanity:PASS:ip -net crypto_sanity_ns link set dev lo up 0 
> nsec
>    test_crypto_sanity:PASS:crypto_sanity__load 0 nsec
>    open_netns:PASS:malloc token 0 nsec
>    open_netns:PASS:open /proc/self/ns/net 0 nsec
>    open_netns:PASS:open netns fd 0 nsec
>    open_netns:PASS:setns 0 nsec
>    test_crypto_sanity:PASS:open_netns 0 nsec
>    test_crypto_sanity:PASS:if_nametoindex lo 0 nsec
>    test_crypto_sanity:PASS:crypto_sanity__attach 0 nsec
>    test_crypto_sanity:PASS:skb_crypto_setup fd 0 nsec
>    test_crypto_sanity:PASS:skb_crypto_setup 0 nsec
>    test_crypto_sanity:PASS:skb_crypto_setup retval 0 nsec
>    test_crypto_sanity:FAIL:skb_crypto_setup status unexpected error: -95 
> (errno 2)
>    libbpf: Kernel error message: Parent Qdisc doesn't exists
>    close_netns:PASS:setns 0 nsec
> Test Results:
>               bpftool: PASS
>   test_progs-no_alu32: FAIL (returned 1)
>              shutdown: CLEAN
> Error: Process completed with exit code 1.

Re: [PATCH bpf-next 1/2] bpf: add skcipher API support to TC/XDP programs

[Jakub Kicinski]

On Wed, 25 Oct 2023 18:59:37 -0700 Vadim Fedorenko wrote:
> Add crypto API support to BPF to be able to decrypt or encrypt packets
> in TC/XDP BPF programs. Only symmetric key ciphers are supported for
> now. Special care should be taken for initialization part of crypto algo
> because crypto_alloc_sync_skcipher() doesn't work with preemtion
> disabled, it can be run only in sleepable BPF program. Also async crypto
> is not supported because of the very same issue - TC/XDP BPF programs
> are not sleepable.

Do CC crypto@ for the next version, please.

> +/**
> + * struct bpf_crypto_skcipher_ctx - refcounted BPF sync skcipher context structure
> + * @tfm:	The pointer to crypto_sync_skcipher 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.
> + */
> +

spurious newline?

> +struct bpf_crypto_skcipher_ctx {

> +/**
> + * bpf_crypto_skcipher_ctx_acquire() - Acquire a reference to a BPF crypto context.

The contexts are refcounted and can be placed in maps?
Does anything prevent them from being used simultaneously 
by difference CPUs?

> +	case BPF_DYNPTR_TYPE_SKB:
> +		return skb_pointer_if_linear(ptr->data, ptr->offset, __bpf_dynptr_size(ptr));

dynptr takes care of checking if skb can be written to?

Re: [PATCH bpf-next 1/2] bpf: add skcipher API support to TC/XDP programs

[Alexei Starovoitov]

On Wed, Oct 25, 2023 at 6:59 PM Vadim Fedorenko <vadfed@meta.com> wrote:
>
> +__bpf_kfunc struct bpf_crypto_skcipher_ctx *
> +bpf_crypto_skcipher_ctx_create(const struct bpf_dynptr_kern *algo, const struct bpf_dynptr_kern *key,
> +                              int *err)
> +{
> +       struct bpf_crypto_skcipher_ctx *ctx;
> +
> +       if (__bpf_dynptr_size(algo) > CRYPTO_MAX_ALG_NAME) {
> +               *err = -EINVAL;
> +               return NULL;
> +       }
> +
> +       if (!crypto_has_skcipher(algo->data, CRYPTO_ALG_TYPE_SKCIPHER, CRYPTO_ALG_TYPE_MASK)) {
> +               *err = -EOPNOTSUPP;
> +               return NULL;
> +       }
> +
> +       ctx = bpf_mem_cache_alloc(&bpf_crypto_ctx_ma);

Since this kfunc is sleepable, just kmalloc(GFP_KERNEL) here.
No need to use bpf_mem_alloc.

Re: [PATCH bpf-next 1/2] bpf: add skcipher API support to TC/XDP programs

[Vadim Fedorenko]

On 26.10.2023 22:47, Jakub Kicinski wrote:
> On Wed, 25 Oct 2023 18:59:37 -0700 Vadim Fedorenko wrote:
>> Add crypto API support to BPF to be able to decrypt or encrypt packets
>> in TC/XDP BPF programs. Only symmetric key ciphers are supported for
>> now. Special care should be taken for initialization part of crypto algo
>> because crypto_alloc_sync_skcipher() doesn't work with preemtion
>> disabled, it can be run only in sleepable BPF program. Also async crypto
>> is not supported because of the very same issue - TC/XDP BPF programs
>> are not sleepable.
> 
> Do CC crypto@ for the next version, please.

Sure

>> +/**
>> + * struct bpf_crypto_skcipher_ctx - refcounted BPF sync skcipher context structure
>> + * @tfm:	The pointer to crypto_sync_skcipher 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.
>> + */
>> +
> 
> spurious newline?

yeah, will fix it

>> +struct bpf_crypto_skcipher_ctx {
> 
>> +/**
>> + * bpf_crypto_skcipher_ctx_acquire() - Acquire a reference to a BPF crypto context.
> 
> The contexts are refcounted and can be placed in maps?

Yes, the idea was to avoid allocation of algo object and setting the key on hot
path. And for now there is no way to allocate crypto cipher object in TC/XDP
hook because it uses GFP_KERNEL and delayed module load.

> Does anything prevent them from being used simultaneously
> by difference CPUs?

The algorithm configuration and the key can be used by different CPUs
simultaneously

>> +	case BPF_DYNPTR_TYPE_SKB:
>> +		return skb_pointer_if_linear(ptr->data, ptr->offset, __bpf_dynptr_size(ptr));
> 
> dynptr takes care of checking if skb can be written to?

dynptr is used to take care of size checking, but this particular part is used
to provide plain buffer from skb. I'm really sure if we can (or should) encrypt
or decrypt in-place, so API now assumes that src and dst are different buffers.

Re: [PATCH bpf-next 1/2] bpf: add skcipher API support to TC/XDP programs

[Vadim Fedorenko]

On 26.10.2023 23:53, Alexei Starovoitov wrote:
> On Wed, Oct 25, 2023 at 6:59 PM Vadim Fedorenko <vadfed@meta.com> wrote:
>>
>> +__bpf_kfunc struct bpf_crypto_skcipher_ctx *
>> +bpf_crypto_skcipher_ctx_create(const struct bpf_dynptr_kern *algo, const struct bpf_dynptr_kern *key,
>> +                              int *err)
>> +{
>> +       struct bpf_crypto_skcipher_ctx *ctx;
>> +
>> +       if (__bpf_dynptr_size(algo) > CRYPTO_MAX_ALG_NAME) {
>> +               *err = -EINVAL;
>> +               return NULL;
>> +       }
>> +
>> +       if (!crypto_has_skcipher(algo->data, CRYPTO_ALG_TYPE_SKCIPHER, CRYPTO_ALG_TYPE_MASK)) {
>> +               *err = -EOPNOTSUPP;
>> +               return NULL;
>> +       }
>> +
>> +       ctx = bpf_mem_cache_alloc(&bpf_crypto_ctx_ma);
> 
> Since this kfunc is sleepable, just kmalloc(GFP_KERNEL) here.
> No need to use bpf_mem_alloc.

I was thinking about adding GFP_ATOMIC allocation option to
crypto_alloc_sync_skcipher, it's already implemented for cloning skcipher
object. Then the code can be reused for both sleepable (expect module loading)
and non-sleepable (fail if there is no crypto module loaded) variants without
any changes. But I can implement different allocators for different options.

Re: [PATCH bpf-next 1/2] bpf: add skcipher API support to TC/XDP programs

[Jakub Kicinski]

On Fri, 27 Oct 2023 00:29:29 +0100 Vadim Fedorenko wrote:
> > Does anything prevent them from being used simultaneously
> > by difference CPUs?  
> 
> The algorithm configuration and the key can be used by different CPUs
> simultaneously

Makes sense, got confused ctx vs req. You allocate req on the fly.

> >> +	case BPF_DYNPTR_TYPE_SKB:
> >> +		return skb_pointer_if_linear(ptr->data, ptr->offset, __bpf_dynptr_size(ptr));  
> > 
> > dynptr takes care of checking if skb can be written to?  
> 
> dynptr is used to take care of size checking, but this particular part is used
> to provide plain buffer from skb. I'm really sure if we can (or should) encrypt
> or decrypt in-place, so API now assumes that src and dst are different buffers.

Not sure this answers my question. What I'm asking is basically whether
for destination we need to call __bpf_dynptr_is_rdonly() or something
already checks that.

Re: [PATCH bpf-next 1/2] bpf: add skcipher API support to TC/XDP programs

[Vadim Fedorenko]

On 27/10/2023 02:35, Jakub Kicinski wrote:
> On Fri, 27 Oct 2023 00:29:29 +0100 Vadim Fedorenko wrote:
>>> Does anything prevent them from being used simultaneously
>>> by difference CPUs?
>>
>> The algorithm configuration and the key can be used by different CPUs
>> simultaneously
> 
> Makes sense, got confused ctx vs req. You allocate req on the fly.
> 
>>>> +	case BPF_DYNPTR_TYPE_SKB:
>>>> +		return skb_pointer_if_linear(ptr->data, ptr->offset, __bpf_dynptr_size(ptr));
>>>
>>> dynptr takes care of checking if skb can be written to?
>>
>> dynptr is used to take care of size checking, but this particular part is used
>> to provide plain buffer from skb. I'm really sure if we can (or should) encrypt
>> or decrypt in-place, so API now assumes that src and dst are different buffers.
> 
> Not sure this answers my question. What I'm asking is basically whether
> for destination we need to call __bpf_dynptr_is_rdonly() or something
> already checks that.

ah, good point. I'm not sure how to make it better. the
__bpf_dynptr_data_ptr() code is based on bpf_dynptr_slice() which has
bpf_dynptr_slice_rdwr() variant. I don't think it's good idea to add
local rdwr variant. I can either add 2 parameter to force checking if
dynptr isn't read-only, or I can convert bpf_dynptr_slice* functions to
be wrappers over __bpf_dynptr_slice and reuse it in this code.

Re: [PATCH bpf-next 1/2] bpf: add skcipher API support to TC/XDP programs

[Vadim Fedorenko]

On 27/10/2023 02:35, Jakub Kicinski wrote:
> On Fri, 27 Oct 2023 00:29:29 +0100 Vadim Fedorenko wrote:
>>> Does anything prevent them from being used simultaneously
>>> by difference CPUs?
>>
>> The algorithm configuration and the key can be used by different CPUs
>> simultaneously
> 
> Makes sense, got confused ctx vs req. You allocate req on the fly.
> 
>>>> +	case BPF_DYNPTR_TYPE_SKB:
>>>> +		return skb_pointer_if_linear(ptr->data, ptr->offset, __bpf_dynptr_size(ptr));
>>>
>>> dynptr takes care of checking if skb can be written to?
>>
>> dynptr is used to take care of size checking, but this particular part is used
>> to provide plain buffer from skb. I'm really sure if we can (or should) encrypt
>> or decrypt in-place, so API now assumes that src and dst are different buffers.
> 
> Not sure this answers my question. What I'm asking is basically whether
> for destination we need to call __bpf_dynptr_is_rdonly() or something
> already checks that.

Well, I actually went to simpler implementation. As it's only needed for
dst buffer, move __bpf_dynptr_is_rdonly to helpers and use it to check
dst only and break earlier in case of error. If there will be other
customers of __bpf_dynptr_data_ptr helper, I'll implement it other way.