bpf: crypto: add skcipher to bpf crypto

Implement skcipher crypto in BPF crypto framework.

Signed-off-by: Vadim Fedorenko <[e-mail]>
Acked-by: Herbert Xu <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Martin KaFai Lau <[e-mail]>

MAINTAINERS

···
 F:	kernel/bpf/trampoline.c
 F:	kernel/bpf/verifier.c
 
+BPF [CRYPTO]
+M:	Vadim Fedorenko <[e-mail]>
+L:	[e-mail]
+S:	Maintained
+F:	crypto/bpf_crypto_skcipher.c
+F:	include/linux/bpf_crypto.h
+F:	kernel/bpf/crypto.c
+
 BPF [DOCUMENTATION] (Related to Standardization)
 R:	David Vernet <[e-mail]>
 L:	[e-mail]

crypto/Makefile

···
 crypto_skcipher-y += skcipher.o
 
 obj-$(CONFIG_CRYPTO_SKCIPHER2) += crypto_skcipher.o
+ifeq ($(CONFIG_BPF_SYSCALL),y)
+obj-$(CONFIG_CRYPTO_SKCIPHER2) += bpf_crypto_skcipher.o
+endif
 
 obj-$(CONFIG_CRYPTO_SEQIV) += seqiv.o
 obj-$(CONFIG_CRYPTO_ECHAINIV) += echainiv.o

crypto/bpf_crypto_skcipher.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2024 Meta, Inc */
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/bpf_crypto.h>
+#include <crypto/skcipher.h>
+
+static void *bpf_crypto_lskcipher_alloc_tfm(const char *algo)
+{
+	return crypto_alloc_lskcipher(algo, 0, 0);
+}
+
+static void bpf_crypto_lskcipher_free_tfm(void *tfm)
+{
+	crypto_free_lskcipher(tfm);
+}
+
+static int bpf_crypto_lskcipher_has_algo(const char *algo)
+{
+	return crypto_has_skcipher(algo, CRYPTO_ALG_TYPE_LSKCIPHER, CRYPTO_ALG_TYPE_MASK);
+}
+
+static int bpf_crypto_lskcipher_setkey(void *tfm, const u8 *key, unsigned int keylen)
+{
+	return crypto_lskcipher_setkey(tfm, key, keylen);
+}
+
+static u32 bpf_crypto_lskcipher_get_flags(void *tfm)
+{
+	return crypto_lskcipher_get_flags(tfm);
+}
+
+static unsigned int bpf_crypto_lskcipher_ivsize(void *tfm)
+{
+	return crypto_lskcipher_ivsize(tfm);
+}
+
+static unsigned int bpf_crypto_lskcipher_statesize(void *tfm)
+{
+	return crypto_lskcipher_statesize(tfm);
+}
+
+static int bpf_crypto_lskcipher_encrypt(void *tfm, const u8 *src, u8 *dst,
+					unsigned int len, u8 *siv)
+{
+	return crypto_lskcipher_encrypt(tfm, src, dst, len, siv);
+}
+
+static int bpf_crypto_lskcipher_decrypt(void *tfm, const u8 *src, u8 *dst,
+					unsigned int len, u8 *siv)
+{
+	return crypto_lskcipher_decrypt(tfm, src, dst, len, siv);
+}
+
+static const struct bpf_crypto_type bpf_crypto_lskcipher_type = {
+	.alloc_tfm	= bpf_crypto_lskcipher_alloc_tfm,
+	.free_tfm	= bpf_crypto_lskcipher_free_tfm,
+	.has_algo	= bpf_crypto_lskcipher_has_algo,
+	.setkey		= bpf_crypto_lskcipher_setkey,
+	.encrypt	= bpf_crypto_lskcipher_encrypt,
+	.decrypt	= bpf_crypto_lskcipher_decrypt,
+	.ivsize		= bpf_crypto_lskcipher_ivsize,
+	.statesize	= bpf_crypto_lskcipher_statesize,
+	.get_flags	= bpf_crypto_lskcipher_get_flags,
+	.owner		= THIS_MODULE,
+	.name		= "skcipher",
+};
+
+static int __init bpf_crypto_skcipher_init(void)
+{
+	return bpf_crypto_register_type(&bpf_crypto_lskcipher_type);
+}
+
+static void __exit bpf_crypto_skcipher_exit(void)
+{
+	int err = bpf_crypto_unregister_type(&bpf_crypto_lskcipher_type);
+	WARN_ON_ONCE(err);
+}
+
+module_init(bpf_crypto_skcipher_init);
+module_exit(bpf_crypto_skcipher_exit);
+MODULE_LICENSE("GPL");