@@ -3,6 +3,9 @@
#include <linux/errno.h>
+#include <crypto/aes.h>
+#include <crypto/gf128mul.h>
+
#define GCM_AES_IV_SIZE 12
#define GCM_RFC4106_IV_SIZE 8
#define GCM_RFC4543_IV_SIZE 8
@@ -60,4 +63,62 @@ static inline int crypto_ipsec_check_assoclen(unsigned int assoclen)
return 0;
}
+
+struct gcm_ctx {
+ be128 ghash_key;
+ struct crypto_aes_ctx aes_ctx;
+ unsigned int authsize;
+};
+
+/**
+ * gcm_expandkey - Expands the AES and GHASH keys for the GCM key schedule
+ * @ctx: The data structure that will hold the GCM key schedule
+ * @key: The AES encryption input key
+ * @keysize: The length in bytes of the input key
+ * @authsize: The size in bytes of the GCM authentication tag
+ *
+ * Returns 0 on success, or -EINVAL if @keysize or @authsize contain values
+ * that are not permitted by the GCM specification.
+ */
+int gcm_expandkey(struct gcm_ctx *ctx, const u8 *key,
+ unsigned int keysize, unsigned int authsize);
+
+/**
+ * gcm_encrypt - Perform GCM encryption on a block of data
+ * @ctx: The GCM key schedule
+ * @dst: Pointer to the ciphertext output buffer
+ * @src: Pointer the plaintext (may equal @dst for encryption in place)
+ * @crypt_len: The size in bytes of the plaintext and ciphertext.
+ * @assoc: Pointer to the associated data,
+ * @assoc_len: The size in bytes of the associated data
+ * @iv: The initialization vector (IV) to use for this block of data
+ * (must be 12 bytes in size as per the GCM spec recommendation)
+ * @authtag: The address of the buffer in memory where the authentication
+ * tag should be stored. The buffer is assumed to have space for
+ * @ctx->authsize bytes.
+ */
+void gcm_encrypt(const struct gcm_ctx *ctx, u8 *dst, const u8 *src,
+ int crypt_len, const u8 *assoc, int assoc_len,
+ const u8 iv[GCM_AES_IV_SIZE], u8 *authtag);
+
+/**
+ * gcm_decrypt - Perform GCM encryption on a block of data
+ * @ctx: The GCM key schedule
+ * @dst: Pointer to the plaintext output buffer
+ * @src: Pointer the ciphertext (may equal @dst for decryption in place)
+ * @crypt_len: The size in bytes of the plaintext and ciphertext.
+ * @assoc: Pointer to the associated data,
+ * @assoc_len: The size in bytes of the associated data
+ * @iv: The initialization vector (IV) to use for this block of data
+ * (must be 12 bytes in size as per the GCM spec recommendation)
+ * @authtag: The address of the buffer in memory where the authentication
+ * tag is stored.
+ *
+ * Returns 0 on success, or -EBADMSG if the ciphertext failed authentication.
+ * On failure, no plaintext will be returned.
+ */
+int __must_check gcm_decrypt(const struct gcm_ctx *ctx, u8 *dst, const u8 *src,
+ int crypt_len, const u8 *assoc, int assoc_len,
+ const u8 iv[GCM_AES_IV_SIZE], const u8 *authtag);
+
#endif
@@ -8,6 +8,12 @@ config CRYPTO_LIB_UTILS
config CRYPTO_LIB_AES
tristate
+config CRYPTO_LIB_GCM
+ tristate
+ select CRYPTO_GF128MUL
+ select CRYPTO_LIB_AES
+ select CRYPTO_LIB_UTILS
+
config CRYPTO_LIB_ARC4
tristate
@@ -10,6 +10,9 @@ obj-$(CONFIG_CRYPTO_LIB_CHACHA_GENERIC) += libchacha.o
obj-$(CONFIG_CRYPTO_LIB_AES) += libaes.o
libaes-y := aes.o
+obj-$(CONFIG_CRYPTO_LIB_GCM) += libgcm.o
+libgcm-y := gcm.o
+
obj-$(CONFIG_CRYPTO_LIB_ARC4) += libarc4.o
libarc4-y := arc4.o
new file mode 100644
@@ -0,0 +1,714 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Minimal library implementation of GCM
+ *
+ * Copyright 2022 Google LLC
+ */
+
+#include <linux/module.h>
+
+#include <crypto/algapi.h>
+#include <crypto/gcm.h>
+#include <crypto/ghash.h>
+
+#include <asm/irqflags.h>
+
+static void gcm_encrypt_block(const struct crypto_aes_ctx *ctx, void *dst,
+ const void *src)
+{
+ unsigned long flags;
+
+ /*
+ * In GCM, both the GHASH key derivation and the CTR mode encryption
+ * operate on known plaintext, making them susceptible to timing
+ * attacks on the encryption key. The AES library already mitigates
+ * this risk to some extent by pulling the entire S-box into the caches
+ * before doing any substitutions, but this strategy is more effective
+ * when running with interrupts disabled.
+ */
+ local_irq_save(flags);
+ aes_encrypt(ctx, dst, src);
+ local_irq_restore(flags);
+}
+
+/**
+ * gcm_expandkey - Expands the AES and GHASH keys for the GCM key schedule
+ * @ctx: The data structure that will hold the GCM key schedule
+ * @key: The AES encryption input key
+ * @keysize: The length in bytes of the input key
+ * @authsize: The size in bytes of the GCM authentication tag
+ *
+ * Returns 0 on success, or -EINVAL if @keysize or @authsize contain values
+ * that are not permitted by the GCM specification.
+ */
+int gcm_expandkey(struct gcm_ctx *ctx, const u8 *key,
+ unsigned int keysize, unsigned int authsize)
+{
+ u8 kin[AES_BLOCK_SIZE] = {};
+ int ret;
+
+ ret = crypto_gcm_check_authsize(authsize) ?:
+ aes_expandkey(&ctx->aes_ctx, key, keysize);
+ if (ret)
+ return ret;
+
+ ctx->authsize = authsize;
+ gcm_encrypt_block(&ctx->aes_ctx, &ctx->ghash_key, kin);
+
+ return 0;
+}
+EXPORT_SYMBOL(gcm_expandkey);
+
+static void gcm_ghash(be128 *ghash, const be128 *key, const void *src, int len)
+{
+ while (len > 0) {
+ crypto_xor((u8 *)ghash, src, min(len, GHASH_BLOCK_SIZE));
+ gf128mul_lle(ghash, key);
+
+ src += GHASH_BLOCK_SIZE;
+ len -= GHASH_BLOCK_SIZE;
+ }
+}
+
+static void gcm_mac(const struct gcm_ctx *ctx, const u8 *src, int src_len,
+ const u8 *assoc, int assoc_len, __be32 *ctr, u8 *authtag)
+{
+ be128 tail = { cpu_to_be64(assoc_len * 8), cpu_to_be64(src_len * 8) };
+ u8 buf[AES_BLOCK_SIZE];
+ be128 ghash = {};
+
+ gcm_ghash(&ghash, &ctx->ghash_key, assoc, assoc_len);
+ gcm_ghash(&ghash, &ctx->ghash_key, src, src_len);
+ gcm_ghash(&ghash, &ctx->ghash_key, &tail, sizeof(tail));
+
+ ctr[3] = cpu_to_be32(1);
+ gcm_encrypt_block(&ctx->aes_ctx, buf, ctr);
+ crypto_xor_cpy(authtag, buf, (u8 *)&ghash, ctx->authsize);
+
+ memzero_explicit(&ghash, sizeof(ghash));
+ memzero_explicit(buf, sizeof(buf));
+}
+
+static void gcm_crypt(const struct gcm_ctx *ctx, u8 *dst, const u8 *src,
+ int len, __be32 *ctr)
+{
+ u8 buf[AES_BLOCK_SIZE];
+ unsigned int n = 2;
+
+ while (len > 0) {
+ ctr[3] = cpu_to_be32(n++);
+ gcm_encrypt_block(&ctx->aes_ctx, buf, ctr);
+ crypto_xor_cpy(dst, src, buf, min(len, AES_BLOCK_SIZE));
+
+ dst += AES_BLOCK_SIZE;
+ src += AES_BLOCK_SIZE;
+ len -= AES_BLOCK_SIZE;
+ }
+ memzero_explicit(buf, sizeof(buf));
+}
+
+/**
+ * gcm_encrypt - Perform GCM encryption on a block of data
+ * @ctx: The GCM key schedule
+ * @dst: Pointer to the ciphertext output buffer
+ * @src: Pointer the plaintext (may equal @dst for encryption in place)
+ * @crypt_len: The size in bytes of the plaintext and ciphertext.
+ * @assoc: Pointer to the associated data,
+ * @assoc_len: The size in bytes of the associated data
+ * @iv: The initialization vector (IV) to use for this block of data
+ * (must be 12 bytes in size as per the GCM spec recommendation)
+ * @authtag: The address of the buffer in memory where the authentication
+ * tag should be stored. The buffer is assumed to have space for
+ * @ctx->authsize bytes.
+ */
+void gcm_encrypt(const struct gcm_ctx *ctx, u8 *dst, const u8 *src,
+ int crypt_len, const u8 *assoc, int assoc_len,
+ const u8 iv[GCM_AES_IV_SIZE], u8 *authtag)
+{
+ __be32 ctr[4];
+
+ memcpy(ctr, iv, GCM_AES_IV_SIZE);
+
+ gcm_crypt(ctx, dst, src, crypt_len, ctr);
+ gcm_mac(ctx, dst, crypt_len, assoc, assoc_len, ctr, authtag);
+}
+EXPORT_SYMBOL(gcm_encrypt);
+
+/**
+ * gcm_decrypt - Perform GCM decryption on a block of data
+ * @ctx: The GCM key schedule
+ * @dst: Pointer to the plaintext output buffer
+ * @src: Pointer the ciphertext (may equal @dst for decryption in place)
+ * @crypt_len: The size in bytes of the plaintext and ciphertext.
+ * @assoc: Pointer to the associated data,
+ * @assoc_len: The size in bytes of the associated data
+ * @iv: The initialization vector (IV) to use for this block of data
+ * (must be 12 bytes in size as per the GCM spec recommendation)
+ * @authtag: The address of the buffer in memory where the authentication
+ * tag is stored.
+ *
+ * Returns 0 on success, or -EBADMSG if the ciphertext failed authentication.
+ * On failure, no plaintext will be returned.
+ */
+int __must_check gcm_decrypt(const struct gcm_ctx *ctx, u8 *dst, const u8 *src,
+ int crypt_len, const u8 *assoc, int assoc_len,
+ const u8 iv[GCM_AES_IV_SIZE], const u8 *authtag)
+{
+ u8 tagbuf[AES_BLOCK_SIZE];
+ __be32 ctr[4];
+
+ memcpy(ctr, iv, GCM_AES_IV_SIZE);
+
+ gcm_mac(ctx, src, crypt_len, assoc, assoc_len, ctr, tagbuf);
+ if (crypto_memneq(authtag, tagbuf, ctx->authsize)) {
+ memzero_explicit(tagbuf, sizeof(tagbuf));
+ return -EBADMSG;
+ }
+ gcm_crypt(ctx, dst, src, crypt_len, ctr);
+ return 0;
+}
+EXPORT_SYMBOL(gcm_decrypt);
+
+MODULE_DESCRIPTION("Generic GCM library");
+MODULE_AUTHOR("Ard Biesheuvel <ardb@kernel.org>");
+MODULE_LICENSE("GPL");
+
+#ifndef CONFIG_CRYPTO_MANAGER_DISABLE_TESTS
+
+/*
+ * Test code below. Vectors taken from crypto/testmgr.h
+ */
+
+static const u8 __initconst ctext0[16] =
+ "\x58\xe2\xfc\xce\xfa\x7e\x30\x61"
+ "\x36\x7f\x1d\x57\xa4\xe7\x45\x5a";
+
+static const u8 __initconst ptext1[16];
+
+static const u8 __initconst ctext1[32] =
+ "\x03\x88\xda\xce\x60\xb6\xa3\x92"
+ "\xf3\x28\xc2\xb9\x71\xb2\xfe\x78"
+ "\xab\x6e\x47\xd4\x2c\xec\x13\xbd"
+ "\xf5\x3a\x67\xb2\x12\x57\xbd\xdf";
+
+static const u8 __initconst ptext2[64] =
+ "\xd9\x31\x32\x25\xf8\x84\x06\xe5"
+ "\xa5\x59\x09\xc5\xaf\xf5\x26\x9a"
+ "\x86\xa7\xa9\x53\x15\x34\xf7\xda"
+ "\x2e\x4c\x30\x3d\x8a\x31\x8a\x72"
+ "\x1c\x3c\x0c\x95\x95\x68\x09\x53"
+ "\x2f\xcf\x0e\x24\x49\xa6\xb5\x25"
+ "\xb1\x6a\xed\xf5\xaa\x0d\xe6\x57"
+ "\xba\x63\x7b\x39\x1a\xaf\xd2\x55";
+
+static const u8 __initconst ctext2[80] =
+ "\x42\x83\x1e\xc2\x21\x77\x74\x24"
+ "\x4b\x72\x21\xb7\x84\xd0\xd4\x9c"
+ "\xe3\xaa\x21\x2f\x2c\x02\xa4\xe0"
+ "\x35\xc1\x7e\x23\x29\xac\xa1\x2e"
+ "\x21\xd5\x14\xb2\x54\x66\x93\x1c"
+ "\x7d\x8f\x6a\x5a\xac\x84\xaa\x05"
+ "\x1b\xa3\x0b\x39\x6a\x0a\xac\x97"
+ "\x3d\x58\xe0\x91\x47\x3f\x59\x85"
+ "\x4d\x5c\x2a\xf3\x27\xcd\x64\xa6"
+ "\x2c\xf3\x5a\xbd\x2b\xa6\xfa\xb4";
+
+static const u8 __initconst ptext3[60] =
+ "\xd9\x31\x32\x25\xf8\x84\x06\xe5"
+ "\xa5\x59\x09\xc5\xaf\xf5\x26\x9a"
+ "\x86\xa7\xa9\x53\x15\x34\xf7\xda"
+ "\x2e\x4c\x30\x3d\x8a\x31\x8a\x72"
+ "\x1c\x3c\x0c\x95\x95\x68\x09\x53"
+ "\x2f\xcf\x0e\x24\x49\xa6\xb5\x25"
+ "\xb1\x6a\xed\xf5\xaa\x0d\xe6\x57"
+ "\xba\x63\x7b\x39";
+
+static const u8 __initconst ctext3[76] =
+ "\x42\x83\x1e\xc2\x21\x77\x74\x24"
+ "\x4b\x72\x21\xb7\x84\xd0\xd4\x9c"
+ "\xe3\xaa\x21\x2f\x2c\x02\xa4\xe0"
+ "\x35\xc1\x7e\x23\x29\xac\xa1\x2e"
+ "\x21\xd5\x14\xb2\x54\x66\x93\x1c"
+ "\x7d\x8f\x6a\x5a\xac\x84\xaa\x05"
+ "\x1b\xa3\x0b\x39\x6a\x0a\xac\x97"
+ "\x3d\x58\xe0\x91"
+ "\x5b\xc9\x4f\xbc\x32\x21\xa5\xdb"
+ "\x94\xfa\xe9\x5a\xe7\x12\x1a\x47";
+
+static const u8 __initconst ctext4[16] =
+ "\xcd\x33\xb2\x8a\xc7\x73\xf7\x4b"
+ "\xa0\x0e\xd1\xf3\x12\x57\x24\x35";
+
+static const u8 __initconst ctext5[32] =
+ "\x98\xe7\x24\x7c\x07\xf0\xfe\x41"
+ "\x1c\x26\x7e\x43\x84\xb0\xf6\x00"
+ "\x2f\xf5\x8d\x80\x03\x39\x27\xab"
+ "\x8e\xf4\xd4\x58\x75\x14\xf0\xfb";
+
+static const u8 __initconst ptext6[64] =
+ "\xd9\x31\x32\x25\xf8\x84\x06\xe5"
+ "\xa5\x59\x09\xc5\xaf\xf5\x26\x9a"
+ "\x86\xa7\xa9\x53\x15\x34\xf7\xda"
+ "\x2e\x4c\x30\x3d\x8a\x31\x8a\x72"
+ "\x1c\x3c\x0c\x95\x95\x68\x09\x53"
+ "\x2f\xcf\x0e\x24\x49\xa6\xb5\x25"
+ "\xb1\x6a\xed\xf5\xaa\x0d\xe6\x57"
+ "\xba\x63\x7b\x39\x1a\xaf\xd2\x55";
+
+static const u8 __initconst ctext6[80] =
+ "\x39\x80\xca\x0b\x3c\x00\xe8\x41"
+ "\xeb\x06\xfa\xc4\x87\x2a\x27\x57"
+ "\x85\x9e\x1c\xea\xa6\xef\xd9\x84"
+ "\x62\x85\x93\xb4\x0c\xa1\xe1\x9c"
+ "\x7d\x77\x3d\x00\xc1\x44\xc5\x25"
+ "\xac\x61\x9d\x18\xc8\x4a\x3f\x47"
+ "\x18\xe2\x44\x8b\x2f\xe3\x24\xd9"
+ "\xcc\xda\x27\x10\xac\xad\xe2\x56"
+ "\x99\x24\xa7\xc8\x58\x73\x36\xbf"
+ "\xb1\x18\x02\x4d\xb8\x67\x4a\x14";
+
+static const u8 __initconst ctext7[16] =
+ "\x53\x0f\x8a\xfb\xc7\x45\x36\xb9"
+ "\xa9\x63\xb4\xf1\xc4\xcb\x73\x8b";
+
+static const u8 __initconst ctext8[32] =
+ "\xce\xa7\x40\x3d\x4d\x60\x6b\x6e"
+ "\x07\x4e\xc5\xd3\xba\xf3\x9d\x18"
+ "\xd0\xd1\xc8\xa7\x99\x99\x6b\xf0"
+ "\x26\x5b\x98\xb5\xd4\x8a\xb9\x19";
+
+static const u8 __initconst ptext9[64] =
+ "\xd9\x31\x32\x25\xf8\x84\x06\xe5"
+ "\xa5\x59\x09\xc5\xaf\xf5\x26\x9a"
+ "\x86\xa7\xa9\x53\x15\x34\xf7\xda"
+ "\x2e\x4c\x30\x3d\x8a\x31\x8a\x72"
+ "\x1c\x3c\x0c\x95\x95\x68\x09\x53"
+ "\x2f\xcf\x0e\x24\x49\xa6\xb5\x25"
+ "\xb1\x6a\xed\xf5\xaa\x0d\xe6\x57"
+ "\xba\x63\x7b\x39\x1a\xaf\xd2\x55";
+
+static const u8 __initconst ctext9[80] =
+ "\x52\x2d\xc1\xf0\x99\x56\x7d\x07"
+ "\xf4\x7f\x37\xa3\x2a\x84\x42\x7d"
+ "\x64\x3a\x8c\xdc\xbf\xe5\xc0\xc9"
+ "\x75\x98\xa2\xbd\x25\x55\xd1\xaa"
+ "\x8c\xb0\x8e\x48\x59\x0d\xbb\x3d"
+ "\xa7\xb0\x8b\x10\x56\x82\x88\x38"
+ "\xc5\xf6\x1e\x63\x93\xba\x7a\x0a"
+ "\xbc\xc9\xf6\x62\x89\x80\x15\xad"
+ "\xb0\x94\xda\xc5\xd9\x34\x71\xbd"
+ "\xec\x1a\x50\x22\x70\xe3\xcc\x6c";
+
+static const u8 __initconst ptext10[60] =
+ "\xd9\x31\x32\x25\xf8\x84\x06\xe5"
+ "\xa5\x59\x09\xc5\xaf\xf5\x26\x9a"
+ "\x86\xa7\xa9\x53\x15\x34\xf7\xda"
+ "\x2e\x4c\x30\x3d\x8a\x31\x8a\x72"
+ "\x1c\x3c\x0c\x95\x95\x68\x09\x53"
+ "\x2f\xcf\x0e\x24\x49\xa6\xb5\x25"
+ "\xb1\x6a\xed\xf5\xaa\x0d\xe6\x57"
+ "\xba\x63\x7b\x39";
+
+static const u8 __initconst ctext10[76] =
+ "\x52\x2d\xc1\xf0\x99\x56\x7d\x07"
+ "\xf4\x7f\x37\xa3\x2a\x84\x42\x7d"
+ "\x64\x3a\x8c\xdc\xbf\xe5\xc0\xc9"
+ "\x75\x98\xa2\xbd\x25\x55\xd1\xaa"
+ "\x8c\xb0\x8e\x48\x59\x0d\xbb\x3d"
+ "\xa7\xb0\x8b\x10\x56\x82\x88\x38"
+ "\xc5\xf6\x1e\x63\x93\xba\x7a\x0a"
+ "\xbc\xc9\xf6\x62"
+ "\x76\xfc\x6e\xce\x0f\x4e\x17\x68"
+ "\xcd\xdf\x88\x53\xbb\x2d\x55\x1b";
+
+static const u8 __initconst ptext11[60] =
+ "\xd9\x31\x32\x25\xf8\x84\x06\xe5"
+ "\xa5\x59\x09\xc5\xaf\xf5\x26\x9a"
+ "\x86\xa7\xa9\x53\x15\x34\xf7\xda"
+ "\x2e\x4c\x30\x3d\x8a\x31\x8a\x72"
+ "\x1c\x3c\x0c\x95\x95\x68\x09\x53"
+ "\x2f\xcf\x0e\x24\x49\xa6\xb5\x25"
+ "\xb1\x6a\xed\xf5\xaa\x0d\xe6\x57"
+ "\xba\x63\x7b\x39";
+
+static const u8 __initconst ctext11[76] =
+ "\x39\x80\xca\x0b\x3c\x00\xe8\x41"
+ "\xeb\x06\xfa\xc4\x87\x2a\x27\x57"
+ "\x85\x9e\x1c\xea\xa6\xef\xd9\x84"
+ "\x62\x85\x93\xb4\x0c\xa1\xe1\x9c"
+ "\x7d\x77\x3d\x00\xc1\x44\xc5\x25"
+ "\xac\x61\x9d\x18\xc8\x4a\x3f\x47"
+ "\x18\xe2\x44\x8b\x2f\xe3\x24\xd9"
+ "\xcc\xda\x27\x10"
+ "\x25\x19\x49\x8e\x80\xf1\x47\x8f"
+ "\x37\xba\x55\xbd\x6d\x27\x61\x8c";
+
+static const u8 __initconst ptext12[719] =
+ "\x42\xc1\xcc\x08\x48\x6f\x41\x3f"
+ "\x2f\x11\x66\x8b\x2a\x16\xf0\xe0"
+ "\x58\x83\xf0\xc3\x70\x14\xc0\x5b"
+ "\x3f\xec\x1d\x25\x3c\x51\xd2\x03"
+ "\xcf\x59\x74\x1f\xb2\x85\xb4\x07"
+ "\xc6\x6a\x63\x39\x8a\x5b\xde\xcb"
+ "\xaf\x08\x44\xbd\x6f\x91\x15\xe1"
+ "\xf5\x7a\x6e\x18\xbd\xdd\x61\x50"
+ "\x59\xa9\x97\xab\xbb\x0e\x74\x5c"
+ "\x00\xa4\x43\x54\x04\x54\x9b\x3b"
+ "\x77\xec\xfd\x5c\xa6\xe8\x7b\x08"
+ "\xae\xe6\x10\x3f\x32\x65\xd1\xfc"
+ "\xa4\x1d\x2c\x31\xfb\x33\x7a\xb3"
+ "\x35\x23\xf4\x20\x41\xd4\xad\x82"
+ "\x8b\xa4\xad\x96\x1c\x20\x53\xbe"
+ "\x0e\xa6\xf4\xdc\x78\x49\x3e\x72"
+ "\xb1\xa9\xb5\x83\xcb\x08\x54\xb7"
+ "\xad\x49\x3a\xae\x98\xce\xa6\x66"
+ "\x10\x30\x90\x8c\x55\x83\xd7\x7c"
+ "\x8b\xe6\x53\xde\xd2\x6e\x18\x21"
+ "\x01\x52\xd1\x9f\x9d\xbb\x9c\x73"
+ "\x57\xcc\x89\x09\x75\x9b\x78\x70"
+ "\xed\x26\x97\x4d\xb4\xe4\x0c\xa5"
+ "\xfa\x70\x04\x70\xc6\x96\x1c\x7d"
+ "\x54\x41\x77\xa8\xe3\xb0\x7e\x96"
+ "\x82\xd9\xec\xa2\x87\x68\x55\xf9"
+ "\x8f\x9e\x73\x43\x47\x6a\x08\x36"
+ "\x93\x67\xa8\x2d\xde\xac\x41\xa9"
+ "\x5c\x4d\x73\x97\x0f\x70\x68\xfa"
+ "\x56\x4d\x00\xc2\x3b\x1f\xc8\xb9"
+ "\x78\x1f\x51\x07\xe3\x9a\x13\x4e"
+ "\xed\x2b\x2e\xa3\xf7\x44\xb2\xe7"
+ "\xab\x19\x37\xd9\xba\x76\x5e\xd2"
+ "\xf2\x53\x15\x17\x4c\x6b\x16\x9f"
+ "\x02\x66\x49\xca\x7c\x91\x05\xf2"
+ "\x45\x36\x1e\xf5\x77\xad\x1f\x46"
+ "\xa8\x13\xfb\x63\xb6\x08\x99\x63"
+ "\x82\xa2\xed\xb3\xac\xdf\x43\x19"
+ "\x45\xea\x78\x73\xd9\xb7\x39\x11"
+ "\xa3\x13\x7c\xf8\x3f\xf7\xad\x81"
+ "\x48\x2f\xa9\x5c\x5f\xa0\xf0\x79"
+ "\xa4\x47\x7d\x80\x20\x26\xfd\x63"
+ "\x0a\xc7\x7e\x6d\x75\x47\xff\x76"
+ "\x66\x2e\x8a\x6c\x81\x35\xaf\x0b"
+ "\x2e\x6a\x49\x60\xc1\x10\xe1\xe1"
+ "\x54\x03\xa4\x09\x0c\x37\x7a\x15"
+ "\x23\x27\x5b\x8b\x4b\xa5\x64\x97"
+ "\xae\x4a\x50\x73\x1f\x66\x1c\x5c"
+ "\x03\x25\x3c\x8d\x48\x58\x71\x34"
+ "\x0e\xec\x4e\x55\x1a\x03\x6a\xe5"
+ "\xb6\x19\x2b\x84\x2a\x20\xd1\xea"
+ "\x80\x6f\x96\x0e\x05\x62\xc7\x78"
+ "\x87\x79\x60\x38\x46\xb4\x25\x57"
+ "\x6e\x16\x63\xf8\xad\x6e\xd7\x42"
+ "\x69\xe1\x88\xef\x6e\xd5\xb4\x9a"
+ "\x3c\x78\x6c\x3b\xe5\xa0\x1d\x22"
+ "\x86\x5c\x74\x3a\xeb\x24\x26\xc7"
+ "\x09\xfc\x91\x96\x47\x87\x4f\x1a"
+ "\xd6\x6b\x2c\x18\x47\xc0\xb8\x24"
+ "\xa8\x5a\x4a\x9e\xcb\x03\xe7\x2a"
+ "\x09\xe6\x4d\x9c\x6d\x86\x60\xf5"
+ "\x2f\x48\x69\x37\x9f\xf2\xd2\xcb"
+ "\x0e\x5a\xdd\x6e\x8a\xfb\x6a\xfe"
+ "\x0b\x63\xde\x87\x42\x79\x8a\x68"
+ "\x51\x28\x9b\x7a\xeb\xaf\xb8\x2f"
+ "\x9d\xd1\xc7\x45\x90\x08\xc9\x83"
+ "\xe9\x83\x84\xcb\x28\x69\x09\x69"
+ "\xce\x99\x46\x00\x54\xcb\xd8\x38"
+ "\xf9\x53\x4a\xbf\x31\xce\x57\x15"
+ "\x33\xfa\x96\x04\x33\x42\xe3\xc0"
+ "\xb7\x54\x4a\x65\x7a\x7c\x02\xe6"
+ "\x19\x95\xd0\x0e\x82\x07\x63\xf9"
+ "\xe1\x2b\x2a\xfc\x55\x92\x52\xc9"
+ "\xb5\x9f\x23\x28\x60\xe7\x20\x51"
+ "\x10\xd3\xed\x6d\x9b\xab\xb8\xe2"
+ "\x5d\x9a\x34\xb3\xbe\x9c\x64\xcb"
+ "\x78\xc6\x91\x22\x40\x91\x80\xbe"
+ "\xd7\x78\x5c\x0e\x0a\xdc\x08\xe9"
+ "\x67\x10\xa4\x83\x98\x79\x23\xe7"
+ "\x92\xda\xa9\x22\x16\xb1\xe7\x78"
+ "\xa3\x1c\x6c\x8f\x35\x7c\x4d\x37"
+ "\x2f\x6e\x0b\x50\x5c\x34\xb9\xf9"
+ "\xe6\x3d\x91\x0d\x32\x95\xaa\x3d"
+ "\x48\x11\x06\xbb\x2d\xf2\x63\x88"
+ "\x3f\x73\x09\xe2\x45\x56\x31\x51"
+ "\xfa\x5e\x4e\x62\xf7\x90\xf9\xa9"
+ "\x7d\x7b\x1b\xb1\xc8\x26\x6e\x66"
+ "\xf6\x90\x9a\x7f\xf2\x57\xcc\x23"
+ "\x59\xfa\xfa\xaa\x44\x04\x01\xa7"
+ "\xa4\x78\xdb\x74\x3d\x8b\xb5";
+
+static const u8 __initconst ctext12[735] =
+ "\x84\x0b\xdb\xd5\xb7\xa8\xfe\x20"
+ "\xbb\xb1\x12\x7f\x41\xea\xb3\xc0"
+ "\xa2\xb4\x37\x19\x11\x58\xb6\x0b"
+ "\x4c\x1d\x38\x05\x54\xd1\x16\x73"
+ "\x8e\x1c\x20\x90\xa2\x9a\xb7\x74"
+ "\x47\xe6\xd8\xfc\x18\x3a\xb4\xea"
+ "\xd5\x16\x5a\x2c\x53\x01\x46\xb3"
+ "\x18\x33\x74\x6c\x50\xf2\xe8\xc0"
+ "\x73\xda\x60\x22\xeb\xe3\xe5\x9b"
+ "\x20\x93\x6c\x4b\x37\x99\xb8\x23"
+ "\x3b\x4e\xac\xe8\x5b\xe8\x0f\xb7"
+ "\xc3\x8f\xfb\x4a\x37\xd9\x39\x95"
+ "\x34\xf1\xdb\x8f\x71\xd9\xc7\x0b"
+ "\x02\xf1\x63\xfc\x9b\xfc\xc5\xab"
+ "\xb9\x14\x13\x21\xdf\xce\xaa\x88"
+ "\x44\x30\x1e\xce\x26\x01\x92\xf8"
+ "\x9f\x00\x4b\x0c\x4b\xf7\x5f\xe0"
+ "\x89\xca\x94\x66\x11\x21\x97\xca"
+ "\x3e\x83\x74\x2d\xdb\x4d\x11\xeb"
+ "\x97\xc2\x14\xff\x9e\x1e\xa0\x6b"
+ "\x08\xb4\x31\x2b\x85\xc6\x85\x6c"
+ "\x90\xec\x39\xc0\xec\xb3\xb5\x4e"
+ "\xf3\x9c\xe7\x83\x3a\x77\x0a\xf4"
+ "\x56\xfe\xce\x18\x33\x6d\x0b\x2d"
+ "\x33\xda\xc8\x05\x5c\xb4\x09\x2a"
+ "\xde\x6b\x52\x98\x01\xef\x36\x3d"
+ "\xbd\xf9\x8f\xa8\x3e\xaa\xcd\xd1"
+ "\x01\x2d\x42\x49\xc3\xb6\x84\xbb"
+ "\x48\x96\xe0\x90\x93\x6c\x48\x64"
+ "\xd4\xfa\x7f\x93\x2c\xa6\x21\xc8"
+ "\x7a\x23\x7b\xaa\x20\x56\x12\xae"
+ "\x16\x9d\x94\x0f\x54\xa1\xec\xca"
+ "\x51\x4e\xf2\x39\xf4\xf8\x5f\x04"
+ "\x5a\x0d\xbf\xf5\x83\xa1\x15\xe1"
+ "\xf5\x3c\xd8\x62\xa3\xed\x47\x89"
+ "\x85\x4c\xe5\xdb\xac\x9e\x17\x1d"
+ "\x0c\x09\xe3\x3e\x39\x5b\x4d\x74"
+ "\x0e\xf5\x34\xee\x70\x11\x4c\xfd"
+ "\xdb\x34\xb1\xb5\x10\x3f\x73\xb7"
+ "\xf5\xfa\xed\xb0\x1f\xa5\xcd\x3c"
+ "\x8d\x35\x83\xd4\x11\x44\x6e\x6c"
+ "\x5b\xe0\x0e\x69\xa5\x39\xe5\xbb"
+ "\xa9\x57\x24\x37\xe6\x1f\xdd\xcf"
+ "\x16\x2a\x13\xf9\x6a\x2d\x90\xa0"
+ "\x03\x60\x7a\xed\x69\xd5\x00\x8b"
+ "\x7e\x4f\xcb\xb9\xfa\x91\xb9\x37"
+ "\xc1\x26\xce\x90\x97\x22\x64\x64"
+ "\xc1\x72\x43\x1b\xf6\xac\xc1\x54"
+ "\x8a\x10\x9c\xdd\x8d\xd5\x8e\xb2"
+ "\xe4\x85\xda\xe0\x20\x5f\xf4\xb4"
+ "\x15\xb5\xa0\x8d\x12\x74\x49\x23"
+ "\x3a\xdf\x4a\xd3\xf0\x3b\x89\xeb"
+ "\xf8\xcc\x62\x7b\xfb\x93\x07\x41"
+ "\x61\x26\x94\x58\x70\xa6\x3c\xe4"
+ "\xff\x58\xc4\x13\x3d\xcb\x36\x6b"
+ "\x32\xe5\xb2\x6d\x03\x74\x6f\x76"
+ "\x93\x77\xde\x48\xc4\xfa\x30\x4a"
+ "\xda\x49\x80\x77\x0f\x1c\xbe\x11"
+ "\xc8\x48\xb1\xe5\xbb\xf2\x8a\xe1"
+ "\x96\x2f\x9f\xd1\x8e\x8a\x5c\xe2"
+ "\xf7\xd7\xd8\x54\xf3\x3f\xc4\x91"
+ "\xb8\xfb\x86\xdc\x46\x24\x91\x60"
+ "\x6c\x2f\xc9\x41\x37\x51\x49\x54"
+ "\x09\x81\x21\xf3\x03\x9f\x2b\xe3"
+ "\x1f\x39\x63\xaf\xf4\xd7\x53\x60"
+ "\xa7\xc7\x54\xf9\xee\xb1\xb1\x7d"
+ "\x75\x54\x65\x93\xfe\xb1\x68\x6b"
+ "\x57\x02\xf9\xbb\x0e\xf9\xf8\xbf"
+ "\x01\x12\x27\xb4\xfe\xe4\x79\x7a"
+ "\x40\x5b\x51\x4b\xdf\x38\xec\xb1"
+ "\x6a\x56\xff\x35\x4d\x42\x33\xaa"
+ "\x6f\x1b\xe4\xdc\xe0\xdb\x85\x35"
+ "\x62\x10\xd4\xec\xeb\xc5\x7e\x45"
+ "\x1c\x6f\x17\xca\x3b\x8e\x2d\x66"
+ "\x4f\x4b\x36\x56\xcd\x1b\x59\xaa"
+ "\xd2\x9b\x17\xb9\x58\xdf\x7b\x64"
+ "\x8a\xff\x3b\x9c\xa6\xb5\x48\x9e"
+ "\xaa\xe2\x5d\x09\x71\x32\x5f\xb6"
+ "\x29\xbe\xe7\xc7\x52\x7e\x91\x82"
+ "\x6b\x6d\x33\xe1\x34\x06\x36\x21"
+ "\x5e\xbe\x1e\x2f\x3e\xc1\xfb\xea"
+ "\x49\x2c\xb5\xca\xf7\xb0\x37\xea"
+ "\x1f\xed\x10\x04\xd9\x48\x0d\x1a"
+ "\x1c\xfb\xe7\x84\x0e\x83\x53\x74"
+ "\xc7\x65\xe2\x5c\xe5\xba\x73\x4c"
+ "\x0e\xe1\xb5\x11\x45\x61\x43\x46"
+ "\xaa\x25\x8f\xbd\x85\x08\xfa\x4c"
+ "\x15\xc1\xc0\xd8\xf5\xdc\x16\xbb"
+ "\x7b\x1d\xe3\x87\x57\xa7\x2a\x1d"
+ "\x38\x58\x9e\x8a\x43\xdc\x57"
+ "\xd1\x81\x7d\x2b\xe9\xff\x99\x3a"
+ "\x4b\x24\x52\x58\x55\xe1\x49\x14";
+
+static struct {
+ const u8 *ptext;
+ const u8 *ctext;
+
+ u8 key[AES_MAX_KEY_SIZE];
+ u8 iv[GCM_AES_IV_SIZE];
+ u8 assoc[20];
+
+ int klen;
+ int clen;
+ int plen;
+ int alen;
+} const gcm_tv[] __initconst = {
+ { /* From McGrew & Viega - http://citeseer.ist.psu.edu/656989.html */
+ .klen = 16,
+ .ctext = ctext0,
+ .clen = sizeof(ctext0),
+ }, {
+ .klen = 16,
+ .ptext = ptext1,
+ .plen = sizeof(ptext1),
+ .ctext = ctext1,
+ .clen = sizeof(ctext1),
+ }, {
+ .key = "\xfe\xff\xe9\x92\x86\x65\x73\x1c"
+ "\x6d\x6a\x8f\x94\x67\x30\x83\x08",
+ .klen = 16,
+ .iv = "\xca\xfe\xba\xbe\xfa\xce\xdb\xad"
+ "\xde\xca\xf8\x88",
+ .ptext = ptext2,
+ .plen = sizeof(ptext2),
+ .ctext = ctext2,
+ .clen = sizeof(ctext2),
+ }, {
+ .key = "\xfe\xff\xe9\x92\x86\x65\x73\x1c"
+ "\x6d\x6a\x8f\x94\x67\x30\x83\x08",
+ .klen = 16,
+ .iv = "\xca\xfe\xba\xbe\xfa\xce\xdb\xad"
+ "\xde\xca\xf8\x88",
+ .ptext = ptext3,
+ .plen = sizeof(ptext3),
+ .assoc = "\xfe\xed\xfa\xce\xde\xad\xbe\xef"
+ "\xfe\xed\xfa\xce\xde\xad\xbe\xef"
+ "\xab\xad\xda\xd2",
+ .alen = 20,
+ .ctext = ctext3,
+ .clen = sizeof(ctext3),
+ }, {
+ .klen = 24,
+ .ctext = ctext4,
+ .clen = sizeof(ctext4),
+ }, {
+ .klen = 24,
+ .ptext = ptext1,
+ .plen = sizeof(ptext1),
+ .ctext = ctext5,
+ .clen = sizeof(ctext5),
+ }, {
+ .key = "\xfe\xff\xe9\x92\x86\x65\x73\x1c"
+ "\x6d\x6a\x8f\x94\x67\x30\x83\x08"
+ "\xfe\xff\xe9\x92\x86\x65\x73\x1c",
+ .klen = 24,
+ .iv = "\xca\xfe\xba\xbe\xfa\xce\xdb\xad"
+ "\xde\xca\xf8\x88",
+ .ptext = ptext6,
+ .plen = sizeof(ptext6),
+ .ctext = ctext6,
+ .clen = sizeof(ctext6),
+ }, {
+ .klen = 32,
+ .ctext = ctext7,
+ .clen = sizeof(ctext7),
+ }, {
+ .klen = 32,
+ .ptext = ptext1,
+ .plen = sizeof(ptext1),
+ .ctext = ctext8,
+ .clen = sizeof(ctext8),
+ }, {
+ .key = "\xfe\xff\xe9\x92\x86\x65\x73\x1c"
+ "\x6d\x6a\x8f\x94\x67\x30\x83\x08"
+ "\xfe\xff\xe9\x92\x86\x65\x73\x1c"
+ "\x6d\x6a\x8f\x94\x67\x30\x83\x08",
+ .klen = 32,
+ .iv = "\xca\xfe\xba\xbe\xfa\xce\xdb\xad"
+ "\xde\xca\xf8\x88",
+ .ptext = ptext9,
+ .plen = sizeof(ptext9),
+ .ctext = ctext9,
+ .clen = sizeof(ctext9),
+ }, {
+ .key = "\xfe\xff\xe9\x92\x86\x65\x73\x1c"
+ "\x6d\x6a\x8f\x94\x67\x30\x83\x08"
+ "\xfe\xff\xe9\x92\x86\x65\x73\x1c"
+ "\x6d\x6a\x8f\x94\x67\x30\x83\x08",
+ .klen = 32,
+ .iv = "\xca\xfe\xba\xbe\xfa\xce\xdb\xad"
+ "\xde\xca\xf8\x88",
+ .ptext = ptext10,
+ .plen = sizeof(ptext10),
+ .assoc = "\xfe\xed\xfa\xce\xde\xad\xbe\xef"
+ "\xfe\xed\xfa\xce\xde\xad\xbe\xef"
+ "\xab\xad\xda\xd2",
+ .alen = 20,
+ .ctext = ctext10,
+ .clen = sizeof(ctext10),
+ }, {
+ .key = "\xfe\xff\xe9\x92\x86\x65\x73\x1c"
+ "\x6d\x6a\x8f\x94\x67\x30\x83\x08"
+ "\xfe\xff\xe9\x92\x86\x65\x73\x1c",
+ .klen = 24,
+ .iv = "\xca\xfe\xba\xbe\xfa\xce\xdb\xad"
+ "\xde\xca\xf8\x88",
+ .ptext = ptext11,
+ .plen = sizeof(ptext11),
+ .assoc = "\xfe\xed\xfa\xce\xde\xad\xbe\xef"
+ "\xfe\xed\xfa\xce\xde\xad\xbe\xef"
+ "\xab\xad\xda\xd2",
+ .alen = 20,
+ .ctext = ctext11,
+ .clen = sizeof(ctext11),
+ }, {
+ .key = "\x62\x35\xf8\x95\xfc\xa5\xeb\xf6"
+ "\x0e\x92\x12\x04\xd3\xa1\x3f\x2e"
+ "\x8b\x32\xcf\xe7\x44\xed\x13\x59"
+ "\x04\x38\x77\xb0\xb9\xad\xb4\x38",
+ .klen = 32,
+ .iv = "\x00\xff\xff\xff\xff\x00\x00\xff"
+ "\xff\xff\x00\xff",
+ .ptext = ptext12,
+ .plen = sizeof(ptext12),
+ .ctext = ctext12,
+ .clen = sizeof(ctext12),
+ }
+};
+
+static int __init libgcm_init(void)
+{
+ for (int i = 0; i < ARRAY_SIZE(gcm_tv); i++) {
+ u8 tagbuf[AES_BLOCK_SIZE];
+ int plen = gcm_tv[i].plen;
+ struct gcm_ctx ctx;
+ u8 buf[720];
+
+ if (gcm_expandkey(&ctx, gcm_tv[i].key, gcm_tv[i].klen,
+ gcm_tv[i].clen - plen)) {
+ WARN(1, "gcm_expandkey() failed on vector %d\n", i);
+ return -EINVAL;
+ }
+
+ if (gcm_decrypt(&ctx, buf, gcm_tv[i].ctext, plen,
+ gcm_tv[i].assoc, gcm_tv[i].alen,
+ gcm_tv[i].iv, gcm_tv[i].ctext + plen) ||
+ memcmp(buf, gcm_tv[i].ptext, plen)) {
+ WARN(1, "gcm_decrypt() #1 failed on vector %d\n", i);
+ return -EINVAL;
+ }
+
+ /* encrypt in place */
+ gcm_encrypt(&ctx, buf, buf, plen, gcm_tv[i].assoc,
+ gcm_tv[i].alen, gcm_tv[i].iv, tagbuf);
+ if (memcmp(buf, gcm_tv[i].ctext, plen)) {
+ WARN(1, "gcm_encrypt() failed on vector %d\n", i);
+ return -EINVAL;
+ }
+
+ /* decrypt in place */
+ if (gcm_decrypt(&ctx, buf, buf, plen, gcm_tv[i].assoc,
+ gcm_tv[i].alen, gcm_tv[i].iv, tagbuf) ||
+ memcmp(buf, gcm_tv[i].ptext, plen)) {
+ WARN(1, "gcm_decrypt() #2 failed on vector %d\n", i);
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+module_init(libgcm_init);
+
+static void __exit libgcm_exit(void)
+{
+}
+module_exit(libgcm_exit);
+#endif
Implement a minimal library version of GCM based on the existing library implementations of AES and multiplication in GF(2^128). Using these primitives, GCM can be implemented in a straight-forward manner. GCM has a couple of sharp edges, i.e., the amount of input data processed with the same initialization vector (IV) should be capped to protect the counter from 32-bit rollover (or carry), and the size of the authentication tag should be fixed for a given key. [0] The former concern is addressed trivially, given that the function call API uses 32-bit signed types for the input lengths. It is still up to the caller to avoid IV reuse in general, but this is not something we can police at the implementation level. As for the latter concern, let's make the authentication tag size part of the key schedule, and only permit it to be configured as part of the key expansion routine. Note that table based AES implementations are susceptible to known plaintext timing attacks on the encryption key. The AES library already attempts to mitigate this to some extent, but given that the counter mode encryption used by GCM operates exclusively on known plaintext by construction (the IV and therefore the initial counter value are known to an attacker), let's take some extra care to mitigate this, by calling the AES library with interrupts disabled. [0] https://nvlpubs.nist.gov/nistpubs/legacy/sp/nistspecialpublication800-38d.pdf Cc: "Nikunj A. Dadhania" <nikunj@amd.com> Link: https://lore.kernel.org/all/c6fb9b25-a4b6-2e4a-2dd1-63adda055a49@amd.com/ Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- include/crypto/gcm.h | 61 ++ lib/crypto/Kconfig | 6 + lib/crypto/Makefile | 3 + lib/crypto/gcm.c | 714 ++++++++++++++++++++ 4 files changed, 784 insertions(+)