Drop CRC-32 support for now

I'm dropping CRC-32 support from the kernel patchset until someone needs
it, so remove it from fsverity-utils for now too.

Signed-off-by: Eric Biggers <ebiggers@google.com>

6 files changed, 0 insertions, 213 deletions

diff --git a/cmd_setup.c b/cmd_setup.c
index c598a71..29848f9 100644
--- a/cmd_setup.c
+++ b/cmd_setup.c
@@ -535,14 +535,6 @@ int fsverity_cmd_setup(const struct fsverity_command *cmd,
 		goto out_err;
 	}
 
-	if ((params.signing_key_file || params.signature_file) &&
-	    !params.hash_alg->cryptographic) {
-		error_msg("Signing a file using '%s' checksums does not make sense\n"
-			  "       because '%s' is not a cryptographically secure hash algorithm.",
-			  params.hash_alg->name, params.hash_alg->name);
-		goto out_err;
-	}
-
 	if (!load_elisions_and_patches(&elide_opts, &patch_opts, &params))
 		goto out_err;
 
diff --git a/crc32c_table.h b/crc32c_table.h
deleted file mode 100644
index 822c0a6..0000000
--- a/crc32c_table.h
+++ /dev/null
@@ -1,74 +0,0 @@
-/*
- * crc32c_table.h - data table to accelerate CRC-32C computation
- *
- * This file was automatically generated by scripts/gen_crc32c_table.c
- */
-
-#include <stdint.h>
-
-static const uint32_t crc32c_table[] = {
-	0x00000000, 0xf26b8303, 0xe13b70f7, 0x1350f3f4,
-	0xc79a971f, 0x35f1141c, 0x26a1e7e8, 0xd4ca64eb,
-	0x8ad958cf, 0x78b2dbcc, 0x6be22838, 0x9989ab3b,
-	0x4d43cfd0, 0xbf284cd3, 0xac78bf27, 0x5e133c24,
-	0x105ec76f, 0xe235446c, 0xf165b798, 0x030e349b,
-	0xd7c45070, 0x25afd373, 0x36ff2087, 0xc494a384,
-	0x9a879fa0, 0x68ec1ca3, 0x7bbcef57, 0x89d76c54,
-	0x5d1d08bf, 0xaf768bbc, 0xbc267848, 0x4e4dfb4b,
-	0x20bd8ede, 0xd2d60ddd, 0xc186fe29, 0x33ed7d2a,
-	0xe72719c1, 0x154c9ac2, 0x061c6936, 0xf477ea35,
-	0xaa64d611, 0x580f5512, 0x4b5fa6e6, 0xb93425e5,
-	0x6dfe410e, 0x9f95c20d, 0x8cc531f9, 0x7eaeb2fa,
-	0x30e349b1, 0xc288cab2, 0xd1d83946, 0x23b3ba45,
-	0xf779deae, 0x05125dad, 0x1642ae59, 0xe4292d5a,
-	0xba3a117e, 0x4851927d, 0x5b016189, 0xa96ae28a,
-	0x7da08661, 0x8fcb0562, 0x9c9bf696, 0x6ef07595,
-	0x417b1dbc, 0xb3109ebf, 0xa0406d4b, 0x522bee48,
-	0x86e18aa3, 0x748a09a0, 0x67dafa54, 0x95b17957,
-	0xcba24573, 0x39c9c670, 0x2a993584, 0xd8f2b687,
-	0x0c38d26c, 0xfe53516f, 0xed03a29b, 0x1f682198,
-	0x5125dad3, 0xa34e59d0, 0xb01eaa24, 0x42752927,
-	0x96bf4dcc, 0x64d4cecf, 0x77843d3b, 0x85efbe38,
-	0xdbfc821c, 0x2997011f, 0x3ac7f2eb, 0xc8ac71e8,
-	0x1c661503, 0xee0d9600, 0xfd5d65f4, 0x0f36e6f7,
-	0x61c69362, 0x93ad1061, 0x80fde395, 0x72966096,
-	0xa65c047d, 0x5437877e, 0x4767748a, 0xb50cf789,
-	0xeb1fcbad, 0x197448ae, 0x0a24bb5a, 0xf84f3859,
-	0x2c855cb2, 0xdeeedfb1, 0xcdbe2c45, 0x3fd5af46,
-	0x7198540d, 0x83f3d70e, 0x90a324fa, 0x62c8a7f9,
-	0xb602c312, 0x44694011, 0x5739b3e5, 0xa55230e6,
-	0xfb410cc2, 0x092a8fc1, 0x1a7a7c35, 0xe811ff36,
-	0x3cdb9bdd, 0xceb018de, 0xdde0eb2a, 0x2f8b6829,
-	0x82f63b78, 0x709db87b, 0x63cd4b8f, 0x91a6c88c,
-	0x456cac67, 0xb7072f64, 0xa457dc90, 0x563c5f93,
-	0x082f63b7, 0xfa44e0b4, 0xe9141340, 0x1b7f9043,
-	0xcfb5f4a8, 0x3dde77ab, 0x2e8e845f, 0xdce5075c,
-	0x92a8fc17, 0x60c37f14, 0x73938ce0, 0x81f80fe3,
-	0x55326b08, 0xa759e80b, 0xb4091bff, 0x466298fc,
-	0x1871a4d8, 0xea1a27db, 0xf94ad42f, 0x0b21572c,
-	0xdfeb33c7, 0x2d80b0c4, 0x3ed04330, 0xccbbc033,
-	0xa24bb5a6, 0x502036a5, 0x4370c551, 0xb11b4652,
-	0x65d122b9, 0x97baa1ba, 0x84ea524e, 0x7681d14d,
-	0x2892ed69, 0xdaf96e6a, 0xc9a99d9e, 0x3bc21e9d,
-	0xef087a76, 0x1d63f975, 0x0e330a81, 0xfc588982,
-	0xb21572c9, 0x407ef1ca, 0x532e023e, 0xa145813d,
-	0x758fe5d6, 0x87e466d5, 0x94b49521, 0x66df1622,
-	0x38cc2a06, 0xcaa7a905, 0xd9f75af1, 0x2b9cd9f2,
-	0xff56bd19, 0x0d3d3e1a, 0x1e6dcdee, 0xec064eed,
-	0xc38d26c4, 0x31e6a5c7, 0x22b65633, 0xd0ddd530,
-	0x0417b1db, 0xf67c32d8, 0xe52cc12c, 0x1747422f,
-	0x49547e0b, 0xbb3ffd08, 0xa86f0efc, 0x5a048dff,
-	0x8ecee914, 0x7ca56a17, 0x6ff599e3, 0x9d9e1ae0,
-	0xd3d3e1ab, 0x21b862a8, 0x32e8915c, 0xc083125f,
-	0x144976b4, 0xe622f5b7, 0xf5720643, 0x07198540,
-	0x590ab964, 0xab613a67, 0xb831c993, 0x4a5a4a90,
-	0x9e902e7b, 0x6cfbad78, 0x7fab5e8c, 0x8dc0dd8f,
-	0xe330a81a, 0x115b2b19, 0x020bd8ed, 0xf0605bee,
-	0x24aa3f05, 0xd6c1bc06, 0xc5914ff2, 0x37faccf1,
-	0x69e9f0d5, 0x9b8273d6, 0x88d28022, 0x7ab90321,
-	0xae7367ca, 0x5c18e4c9, 0x4f48173d, 0xbd23943e,
-	0xf36e6f75, 0x0105ec76, 0x12551f82, 0xe03e9c81,
-	0x34f4f86a, 0xc69f7b69, 0xd5cf889d, 0x27a40b9e,
-	0x79b737ba, 0x8bdcb4b9, 0x988c474d, 0x6ae7c44e,
-	0xbe2da0a5, 0x4c4623a6, 0x5f16d052, 0xad7d5351,
-};
diff --git a/hash_algs.c b/hash_algs.c
index 1e46924..e3dfc00 100644
--- a/hash_algs.c
+++ b/hash_algs.c
@@ -14,11 +14,6 @@
 #include "fsverity_uapi.h"
 #include "hash_algs.h"
 
-static void free_hash_ctx(struct hash_ctx *ctx)
-{
-	free(ctx);
-}
-
 /* ========== libcrypto (OpenSSL) wrappers ========== */
 
 struct openssl_hash_ctx {
@@ -104,79 +99,19 @@ static struct hash_ctx *create_sha512_ctx(const struct fsverity_hash_alg *alg)
 	return openssl_digest_ctx_create(alg, EVP_sha512());
 }
 
-/* ========== CRC-32C ========== */
-
-/*
- * There are faster ways to calculate CRC's, but for now we just use the
- * 256-entry table method as it's portable and not too complex.
- */
-
-#include "crc32c_table.h"
-
-struct crc32c_hash_ctx {
-	struct hash_ctx base;	/* must be first */
-	u32 remainder;
-};
-
-static void crc32c_init(struct hash_ctx *_ctx)
-{
-	struct crc32c_hash_ctx *ctx = (void *)_ctx;
-
-	ctx->remainder = ~0;
-}
-
-static void crc32c_update(struct hash_ctx *_ctx, const void *data, size_t size)
-{
-	struct crc32c_hash_ctx *ctx = (void *)_ctx;
-	const u8 *p = data;
-	u32 r = ctx->remainder;
-
-	while (size--)
-		r = (r >> 8) ^ crc32c_table[(u8)r ^ *p++];
-
-	ctx->remainder = r;
-}
-
-static void crc32c_final(struct hash_ctx *_ctx, u8 *digest)
-{
-	struct crc32c_hash_ctx *ctx = (void *)_ctx;
-	__le32 remainder = cpu_to_le32(~ctx->remainder);
-
-	memcpy(digest, &remainder, sizeof(remainder));
-}
-
-static struct hash_ctx *create_crc32c_ctx(const struct fsverity_hash_alg *alg)
-{
-	struct crc32c_hash_ctx *ctx = xzalloc(sizeof(*ctx));
-
-	ctx->base.alg = alg;
-	ctx->base.init = crc32c_init;
-	ctx->base.update = crc32c_update;
-	ctx->base.final = crc32c_final;
-	ctx->base.free = free_hash_ctx;
-	return &ctx->base;
-}
-
 /* ========== Hash algorithm definitions ========== */
 
 const struct fsverity_hash_alg fsverity_hash_algs[] = {
 	[FS_VERITY_ALG_SHA256] = {
 		.name = "sha256",
 		.digest_size = 32,
-		.cryptographic = true,
 		.create_ctx = create_sha256_ctx,
 	},
 	[FS_VERITY_ALG_SHA512] = {
 		.name = "sha512",
 		.digest_size = 64,
-		.cryptographic = true,
 		.create_ctx = create_sha512_ctx,
 	},
-	[FS_VERITY_ALG_CRC32C] = {
-		.name = "crc32c",
-		.digest_size = 4,
-		.create_ctx = create_crc32c_ctx,
-	},
 };
 
 const struct fsverity_hash_alg *find_hash_alg_by_name(const char *name)
diff --git a/hash_algs.h b/hash_algs.h
index 3cb0a98..7a4662f 100644
--- a/hash_algs.h
+++ b/hash_algs.h
@@ -9,7 +9,6 @@
 struct fsverity_hash_alg {
 	const char *name;
 	unsigned int digest_size;
-	bool cryptographic;
 	struct hash_ctx *(*create_ctx)(const struct fsverity_hash_alg *alg);
 };
 
diff --git a/scripts/gen_crc32c_table.c b/scripts/gen_crc32c_table.c
deleted file mode 100644
index 656a349..0000000
--- a/scripts/gen_crc32c_table.c
+++ /dev/null
@@ -1,64 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * Generate a table for CRC-32C calculation.
- *
- * Copyright (C) 2018 Google LLC
- *
- * Written by Eric Biggers.
- */
-
-#include <stdint.h>
-#include <stdio.h>
-
-/*
- * This is the CRC-32C (Castagnoli) polynomial: x^32+x^28+x^27+x^26+x^25+x^23+
- * x^22+x^20+x^19+x^18+x^14+x^13+x^11+x^10+x^9+x^8+x^6+x^0, with the polynomial
- * coefficients mapped to bits using the "little endian" convention.
- */
-#define CRC32C_POLY_LE	0x82F63B78
-
-static uint32_t crc32c_update_bit(uint32_t remainder, uint8_t bit)
-{
-	return (remainder >> 1) ^
-		(((remainder ^ bit) & 1) ? CRC32C_POLY_LE : 0);
-}
-
-static uint32_t crc32c_update_byte(uint32_t remainder, uint8_t byte)
-{
-	int bit;
-
-	for (bit = 0; bit < 8; bit++, byte >>= 1)
-		remainder = crc32c_update_bit(remainder, byte & 1);
-	return remainder;
-}
-
-static uint32_t crc32c_table[256];
-
-int main(void)
-{
-	int i, j;
-
-	for (i = 0; i < 256; i++)
-		crc32c_table[i] = crc32c_update_byte(0, i);
-
-	printf("/*\n");
-	printf(" * crc32c_table.h - data table to accelerate CRC-32C computation\n");
-	printf(" *\n");
-	printf(" * This file was automatically generated by scripts/gen_crc32c_table.c\n");
-	printf(" */\n");
-	printf("\n");
-	printf("#include <stdint.h>\n");
-	printf("\n");
-	printf("static const uint32_t crc32c_table[] = {\n");
-	for (i = 0; i < 64; i++) {
-		printf("\t");
-		for (j = 0; j < 4; j++) {
-			printf("0x%08x,", crc32c_table[i * 4 + j]);
-			if (j != 3)
-				printf(" ");
-		}
-		printf("\n");
-	}
-	printf("};\n");
-	return 0;
-}
diff --git a/sign.c b/sign.c
index 20fecfa..556561e 100644
--- a/sign.c
+++ b/sign.c
@@ -395,7 +395,6 @@ static bool sign_data(const void *data_to_sign, size_t data_size,
 		goto out;
 
 	OpenSSL_add_all_digests();
-	ASSERT(hash_alg->cryptographic);
 	md = EVP_get_digestbyname(hash_alg->name);
 	if (!md) {
 		fprintf(stderr,