| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright IBM Corp. 2006, 2015 |
| * Author(s): Jan Glauber <jan.glauber@de.ibm.com> |
| * Harald Freudenberger <freude@de.ibm.com> |
| * Driver for the s390 pseudo random number generator |
| */ |
| |
| #define KMSG_COMPONENT "prng" |
| #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
| |
| #include <linux/fs.h> |
| #include <linux/fips.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/device.h> |
| #include <linux/miscdevice.h> |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/mutex.h> |
| #include <linux/cpufeature.h> |
| #include <linux/random.h> |
| #include <linux/slab.h> |
| #include <linux/sched/signal.h> |
| |
| #include <asm/debug.h> |
| #include <linux/uaccess.h> |
| #include <asm/timex.h> |
| #include <asm/cpacf.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("IBM Corporation"); |
| MODULE_DESCRIPTION("s390 PRNG interface"); |
| |
| |
| #define PRNG_MODE_AUTO 0 |
| #define PRNG_MODE_TDES 1 |
| #define PRNG_MODE_SHA512 2 |
| |
| static unsigned int prng_mode = PRNG_MODE_AUTO; |
| module_param_named(mode, prng_mode, int, 0); |
| MODULE_PARM_DESC(prng_mode, "PRNG mode: 0 - auto, 1 - TDES, 2 - SHA512"); |
| |
| |
| #define PRNG_CHUNKSIZE_TDES_MIN 8 |
| #define PRNG_CHUNKSIZE_TDES_MAX (64*1024) |
| #define PRNG_CHUNKSIZE_SHA512_MIN 64 |
| #define PRNG_CHUNKSIZE_SHA512_MAX (64*1024) |
| |
| static unsigned int prng_chunk_size = 256; |
| module_param_named(chunksize, prng_chunk_size, int, 0); |
| MODULE_PARM_DESC(prng_chunk_size, "PRNG read chunk size in bytes"); |
| |
| |
| #define PRNG_RESEED_LIMIT_TDES 4096 |
| #define PRNG_RESEED_LIMIT_TDES_LOWER 4096 |
| #define PRNG_RESEED_LIMIT_SHA512 100000 |
| #define PRNG_RESEED_LIMIT_SHA512_LOWER 10000 |
| |
| static unsigned int prng_reseed_limit; |
| module_param_named(reseed_limit, prng_reseed_limit, int, 0); |
| MODULE_PARM_DESC(prng_reseed_limit, "PRNG reseed limit"); |
| |
| static bool trng_available; |
| |
| /* |
| * Any one who considers arithmetical methods of producing random digits is, |
| * of course, in a state of sin. -- John von Neumann |
| */ |
| |
| static int prng_errorflag; |
| |
| #define PRNG_GEN_ENTROPY_FAILED 1 |
| #define PRNG_SELFTEST_FAILED 2 |
| #define PRNG_INSTANTIATE_FAILED 3 |
| #define PRNG_SEED_FAILED 4 |
| #define PRNG_RESEED_FAILED 5 |
| #define PRNG_GEN_FAILED 6 |
| |
| struct prng_ws_s { |
| u8 parm_block[32]; |
| u32 reseed_counter; |
| u64 byte_counter; |
| }; |
| |
| struct prno_ws_s { |
| u32 res; |
| u32 reseed_counter; |
| u64 stream_bytes; |
| u8 V[112]; |
| u8 C[112]; |
| }; |
| |
| struct prng_data_s { |
| struct mutex mutex; |
| union { |
| struct prng_ws_s prngws; |
| struct prno_ws_s prnows; |
| }; |
| u8 *buf; |
| u32 rest; |
| u8 *prev; |
| }; |
| |
| static struct prng_data_s *prng_data; |
| |
| /* initial parameter block for tdes mode, copied from libica */ |
| static const u8 initial_parm_block[32] __initconst = { |
| 0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52, |
| 0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4, |
| 0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF, |
| 0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0 }; |
| |
| |
| /*** helper functions ***/ |
| |
| /* |
| * generate_entropy: |
| * This function fills a given buffer with random bytes. The entropy within |
| * the random bytes given back is assumed to have at least 50% - meaning |
| * a 64 bytes buffer has at least 64 * 8 / 2 = 256 bits of entropy. |
| * Within the function the entropy generation is done in junks of 64 bytes. |
| * So the caller should also ask for buffer fill in multiples of 64 bytes. |
| * The generation of the entropy is based on the assumption that every stckf() |
| * invocation produces 0.5 bits of entropy. To accumulate 256 bits of entropy |
| * at least 512 stckf() values are needed. The entropy relevant part of the |
| * stckf value is bit 51 (counting starts at the left with bit nr 0) so |
| * here we use the lower 4 bytes and exor the values into 2k of bufferspace. |
| * To be on the save side, if there is ever a problem with stckf() the |
| * other half of the page buffer is filled with bytes from urandom via |
| * get_random_bytes(), so this function consumes 2k of urandom for each |
| * requested 64 bytes output data. Finally the buffer page is condensed into |
| * a 64 byte value by hashing with a SHA512 hash. |
| */ |
| static int generate_entropy(u8 *ebuf, size_t nbytes) |
| { |
| int n, ret = 0; |
| u8 *pg, pblock[80] = { |
| /* 8 x 64 bit init values */ |
| 0x6A, 0x09, 0xE6, 0x67, 0xF3, 0xBC, 0xC9, 0x08, |
| 0xBB, 0x67, 0xAE, 0x85, 0x84, 0xCA, 0xA7, 0x3B, |
| 0x3C, 0x6E, 0xF3, 0x72, 0xFE, 0x94, 0xF8, 0x2B, |
| 0xA5, 0x4F, 0xF5, 0x3A, 0x5F, 0x1D, 0x36, 0xF1, |
| 0x51, 0x0E, 0x52, 0x7F, 0xAD, 0xE6, 0x82, 0xD1, |
| 0x9B, 0x05, 0x68, 0x8C, 0x2B, 0x3E, 0x6C, 0x1F, |
| 0x1F, 0x83, 0xD9, 0xAB, 0xFB, 0x41, 0xBD, 0x6B, |
| 0x5B, 0xE0, 0xCD, 0x19, 0x13, 0x7E, 0x21, 0x79, |
| /* 128 bit counter total message bit length */ |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x00 }; |
| |
| /* allocate one page stckf buffer */ |
| pg = (u8 *) __get_free_page(GFP_KERNEL); |
| if (!pg) { |
| prng_errorflag = PRNG_GEN_ENTROPY_FAILED; |
| return -ENOMEM; |
| } |
| |
| /* fill the ebuf in chunks of 64 byte each */ |
| while (nbytes) { |
| /* fill lower 2k with urandom bytes */ |
| get_random_bytes(pg, PAGE_SIZE / 2); |
| /* exor upper 2k with 512 stckf values, offset 4 bytes each */ |
| for (n = 0; n < 512; n++) { |
| int offset = (PAGE_SIZE / 2) + (n * 4) - 4; |
| u64 *p = (u64 *)(pg + offset); |
| *p ^= get_tod_clock_fast(); |
| } |
| /* hash over the filled page */ |
| cpacf_klmd(CPACF_KLMD_SHA_512, pblock, pg, PAGE_SIZE); |
| n = (nbytes < 64) ? nbytes : 64; |
| memcpy(ebuf, pblock, n); |
| ret += n; |
| ebuf += n; |
| nbytes -= n; |
| } |
| |
| memzero_explicit(pblock, sizeof(pblock)); |
| memzero_explicit(pg, PAGE_SIZE); |
| free_page((unsigned long)pg); |
| return ret; |
| } |
| |
| |
| /*** tdes functions ***/ |
| |
| static void prng_tdes_add_entropy(void) |
| { |
| __u64 entropy[4]; |
| unsigned int i; |
| |
| for (i = 0; i < 16; i++) { |
| cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block, |
| (char *) entropy, (char *) entropy, |
| sizeof(entropy)); |
| memcpy(prng_data->prngws.parm_block, entropy, sizeof(entropy)); |
| } |
| } |
| |
| |
| static void prng_tdes_seed(int nbytes) |
| { |
| char buf[16]; |
| int i = 0; |
| |
| BUG_ON(nbytes > sizeof(buf)); |
| |
| get_random_bytes(buf, nbytes); |
| |
| /* Add the entropy */ |
| while (nbytes >= 8) { |
| *((__u64 *)prng_data->prngws.parm_block) ^= *((__u64 *)(buf+i)); |
| prng_tdes_add_entropy(); |
| i += 8; |
| nbytes -= 8; |
| } |
| prng_tdes_add_entropy(); |
| prng_data->prngws.reseed_counter = 0; |
| } |
| |
| |
| static int __init prng_tdes_instantiate(void) |
| { |
| int datalen; |
| |
| pr_debug("prng runs in TDES mode with " |
| "chunksize=%d and reseed_limit=%u\n", |
| prng_chunk_size, prng_reseed_limit); |
| |
| /* memory allocation, prng_data struct init, mutex init */ |
| datalen = sizeof(struct prng_data_s) + prng_chunk_size; |
| prng_data = kzalloc(datalen, GFP_KERNEL); |
| if (!prng_data) { |
| prng_errorflag = PRNG_INSTANTIATE_FAILED; |
| return -ENOMEM; |
| } |
| mutex_init(&prng_data->mutex); |
| prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s); |
| memcpy(prng_data->prngws.parm_block, initial_parm_block, 32); |
| |
| /* initialize the PRNG, add 128 bits of entropy */ |
| prng_tdes_seed(16); |
| |
| return 0; |
| } |
| |
| |
| static void prng_tdes_deinstantiate(void) |
| { |
| pr_debug("The prng module stopped " |
| "after running in triple DES mode\n"); |
| kfree_sensitive(prng_data); |
| } |
| |
| |
| /*** sha512 functions ***/ |
| |
| static int __init prng_sha512_selftest(void) |
| { |
| /* NIST DRBG testvector for Hash Drbg, Sha-512, Count #0 */ |
| static const u8 seed[] __initconst = { |
| 0x6b, 0x50, 0xa7, 0xd8, 0xf8, 0xa5, 0x5d, 0x7a, |
| 0x3d, 0xf8, 0xbb, 0x40, 0xbc, 0xc3, 0xb7, 0x22, |
| 0xd8, 0x70, 0x8d, 0xe6, 0x7f, 0xda, 0x01, 0x0b, |
| 0x03, 0xc4, 0xc8, 0x4d, 0x72, 0x09, 0x6f, 0x8c, |
| 0x3e, 0xc6, 0x49, 0xcc, 0x62, 0x56, 0xd9, 0xfa, |
| 0x31, 0xdb, 0x7a, 0x29, 0x04, 0xaa, 0xf0, 0x25 }; |
| static const u8 V0[] __initconst = { |
| 0x00, 0xad, 0xe3, 0x6f, 0x9a, 0x01, 0xc7, 0x76, |
| 0x61, 0x34, 0x35, 0xf5, 0x4e, 0x24, 0x74, 0x22, |
| 0x21, 0x9a, 0x29, 0x89, 0xc7, 0x93, 0x2e, 0x60, |
| 0x1e, 0xe8, 0x14, 0x24, 0x8d, 0xd5, 0x03, 0xf1, |
| 0x65, 0x5d, 0x08, 0x22, 0x72, 0xd5, 0xad, 0x95, |
| 0xe1, 0x23, 0x1e, 0x8a, 0xa7, 0x13, 0xd9, 0x2b, |
| 0x5e, 0xbc, 0xbb, 0x80, 0xab, 0x8d, 0xe5, 0x79, |
| 0xab, 0x5b, 0x47, 0x4e, 0xdd, 0xee, 0x6b, 0x03, |
| 0x8f, 0x0f, 0x5c, 0x5e, 0xa9, 0x1a, 0x83, 0xdd, |
| 0xd3, 0x88, 0xb2, 0x75, 0x4b, 0xce, 0x83, 0x36, |
| 0x57, 0x4b, 0xf1, 0x5c, 0xca, 0x7e, 0x09, 0xc0, |
| 0xd3, 0x89, 0xc6, 0xe0, 0xda, 0xc4, 0x81, 0x7e, |
| 0x5b, 0xf9, 0xe1, 0x01, 0xc1, 0x92, 0x05, 0xea, |
| 0xf5, 0x2f, 0xc6, 0xc6, 0xc7, 0x8f, 0xbc, 0xf4 }; |
| static const u8 C0[] __initconst = { |
| 0x00, 0xf4, 0xa3, 0xe5, 0xa0, 0x72, 0x63, 0x95, |
| 0xc6, 0x4f, 0x48, 0xd0, 0x8b, 0x5b, 0x5f, 0x8e, |
| 0x6b, 0x96, 0x1f, 0x16, 0xed, 0xbc, 0x66, 0x94, |
| 0x45, 0x31, 0xd7, 0x47, 0x73, 0x22, 0xa5, 0x86, |
| 0xce, 0xc0, 0x4c, 0xac, 0x63, 0xb8, 0x39, 0x50, |
| 0xbf, 0xe6, 0x59, 0x6c, 0x38, 0x58, 0x99, 0x1f, |
| 0x27, 0xa7, 0x9d, 0x71, 0x2a, 0xb3, 0x7b, 0xf9, |
| 0xfb, 0x17, 0x86, 0xaa, 0x99, 0x81, 0xaa, 0x43, |
| 0xe4, 0x37, 0xd3, 0x1e, 0x6e, 0xe5, 0xe6, 0xee, |
| 0xc2, 0xed, 0x95, 0x4f, 0x53, 0x0e, 0x46, 0x8a, |
| 0xcc, 0x45, 0xa5, 0xdb, 0x69, 0x0d, 0x81, 0xc9, |
| 0x32, 0x92, 0xbc, 0x8f, 0x33, 0xe6, 0xf6, 0x09, |
| 0x7c, 0x8e, 0x05, 0x19, 0x0d, 0xf1, 0xb6, 0xcc, |
| 0xf3, 0x02, 0x21, 0x90, 0x25, 0xec, 0xed, 0x0e }; |
| static const u8 random[] __initconst = { |
| 0x95, 0xb7, 0xf1, 0x7e, 0x98, 0x02, 0xd3, 0x57, |
| 0x73, 0x92, 0xc6, 0xa9, 0xc0, 0x80, 0x83, 0xb6, |
| 0x7d, 0xd1, 0x29, 0x22, 0x65, 0xb5, 0xf4, 0x2d, |
| 0x23, 0x7f, 0x1c, 0x55, 0xbb, 0x9b, 0x10, 0xbf, |
| 0xcf, 0xd8, 0x2c, 0x77, 0xa3, 0x78, 0xb8, 0x26, |
| 0x6a, 0x00, 0x99, 0x14, 0x3b, 0x3c, 0x2d, 0x64, |
| 0x61, 0x1e, 0xee, 0xb6, 0x9a, 0xcd, 0xc0, 0x55, |
| 0x95, 0x7c, 0x13, 0x9e, 0x8b, 0x19, 0x0c, 0x7a, |
| 0x06, 0x95, 0x5f, 0x2c, 0x79, 0x7c, 0x27, 0x78, |
| 0xde, 0x94, 0x03, 0x96, 0xa5, 0x01, 0xf4, 0x0e, |
| 0x91, 0x39, 0x6a, 0xcf, 0x8d, 0x7e, 0x45, 0xeb, |
| 0xdb, 0xb5, 0x3b, 0xbf, 0x8c, 0x97, 0x52, 0x30, |
| 0xd2, 0xf0, 0xff, 0x91, 0x06, 0xc7, 0x61, 0x19, |
| 0xae, 0x49, 0x8e, 0x7f, 0xbc, 0x03, 0xd9, 0x0f, |
| 0x8e, 0x4c, 0x51, 0x62, 0x7a, 0xed, 0x5c, 0x8d, |
| 0x42, 0x63, 0xd5, 0xd2, 0xb9, 0x78, 0x87, 0x3a, |
| 0x0d, 0xe5, 0x96, 0xee, 0x6d, 0xc7, 0xf7, 0xc2, |
| 0x9e, 0x37, 0xee, 0xe8, 0xb3, 0x4c, 0x90, 0xdd, |
| 0x1c, 0xf6, 0xa9, 0xdd, 0xb2, 0x2b, 0x4c, 0xbd, |
| 0x08, 0x6b, 0x14, 0xb3, 0x5d, 0xe9, 0x3d, 0xa2, |
| 0xd5, 0xcb, 0x18, 0x06, 0x69, 0x8c, 0xbd, 0x7b, |
| 0xbb, 0x67, 0xbf, 0xe3, 0xd3, 0x1f, 0xd2, 0xd1, |
| 0xdb, 0xd2, 0xa1, 0xe0, 0x58, 0xa3, 0xeb, 0x99, |
| 0xd7, 0xe5, 0x1f, 0x1a, 0x93, 0x8e, 0xed, 0x5e, |
| 0x1c, 0x1d, 0xe2, 0x3a, 0x6b, 0x43, 0x45, 0xd3, |
| 0x19, 0x14, 0x09, 0xf9, 0x2f, 0x39, 0xb3, 0x67, |
| 0x0d, 0x8d, 0xbf, 0xb6, 0x35, 0xd8, 0xe6, 0xa3, |
| 0x69, 0x32, 0xd8, 0x10, 0x33, 0xd1, 0x44, 0x8d, |
| 0x63, 0xb4, 0x03, 0xdd, 0xf8, 0x8e, 0x12, 0x1b, |
| 0x6e, 0x81, 0x9a, 0xc3, 0x81, 0x22, 0x6c, 0x13, |
| 0x21, 0xe4, 0xb0, 0x86, 0x44, 0xf6, 0x72, 0x7c, |
| 0x36, 0x8c, 0x5a, 0x9f, 0x7a, 0x4b, 0x3e, 0xe2 }; |
| |
| u8 buf[sizeof(random)]; |
| struct prno_ws_s ws; |
| |
| memset(&ws, 0, sizeof(ws)); |
| |
| /* initial seed */ |
| cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, |
| &ws, NULL, 0, seed, sizeof(seed)); |
| |
| /* check working states V and C */ |
| if (memcmp(ws.V, V0, sizeof(V0)) != 0 |
| || memcmp(ws.C, C0, sizeof(C0)) != 0) { |
| pr_err("The prng self test state test " |
| "for the SHA-512 mode failed\n"); |
| prng_errorflag = PRNG_SELFTEST_FAILED; |
| return -EIO; |
| } |
| |
| /* generate random bytes */ |
| cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, |
| &ws, buf, sizeof(buf), NULL, 0); |
| cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, |
| &ws, buf, sizeof(buf), NULL, 0); |
| |
| /* check against expected data */ |
| if (memcmp(buf, random, sizeof(random)) != 0) { |
| pr_err("The prng self test data test " |
| "for the SHA-512 mode failed\n"); |
| prng_errorflag = PRNG_SELFTEST_FAILED; |
| return -EIO; |
| } |
| |
| return 0; |
| } |
| |
| |
| static int __init prng_sha512_instantiate(void) |
| { |
| int ret, datalen, seedlen; |
| u8 seed[128 + 16]; |
| |
| pr_debug("prng runs in SHA-512 mode " |
| "with chunksize=%d and reseed_limit=%u\n", |
| prng_chunk_size, prng_reseed_limit); |
| |
| /* memory allocation, prng_data struct init, mutex init */ |
| datalen = sizeof(struct prng_data_s) + prng_chunk_size; |
| if (fips_enabled) |
| datalen += prng_chunk_size; |
| prng_data = kzalloc(datalen, GFP_KERNEL); |
| if (!prng_data) { |
| prng_errorflag = PRNG_INSTANTIATE_FAILED; |
| return -ENOMEM; |
| } |
| mutex_init(&prng_data->mutex); |
| prng_data->buf = ((u8 *)prng_data) + sizeof(struct prng_data_s); |
| |
| /* selftest */ |
| ret = prng_sha512_selftest(); |
| if (ret) |
| goto outfree; |
| |
| /* generate initial seed, we need at least 256 + 128 bits entropy. */ |
| if (trng_available) { |
| /* |
| * Trng available, so use it. The trng works in chunks of |
| * 32 bytes and produces 100% entropy. So we pull 64 bytes |
| * which gives us 512 bits entropy. |
| */ |
| seedlen = 2 * 32; |
| cpacf_trng(NULL, 0, seed, seedlen); |
| } else { |
| /* |
| * No trng available, so use the generate_entropy() function. |
| * This function works in 64 byte junks and produces |
| * 50% entropy. So we pull 2*64 bytes which gives us 512 bits |
| * of entropy. |
| */ |
| seedlen = 2 * 64; |
| ret = generate_entropy(seed, seedlen); |
| if (ret != seedlen) |
| goto outfree; |
| } |
| |
| /* append the seed by 16 bytes of unique nonce */ |
| store_tod_clock_ext((union tod_clock *)(seed + seedlen)); |
| seedlen += 16; |
| |
| /* now initial seed of the prno drng */ |
| cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, |
| &prng_data->prnows, NULL, 0, seed, seedlen); |
| memzero_explicit(seed, sizeof(seed)); |
| |
| /* if fips mode is enabled, generate a first block of random |
| bytes for the FIPS 140-2 Conditional Self Test */ |
| if (fips_enabled) { |
| prng_data->prev = prng_data->buf + prng_chunk_size; |
| cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, |
| &prng_data->prnows, |
| prng_data->prev, prng_chunk_size, NULL, 0); |
| } |
| |
| return 0; |
| |
| outfree: |
| kfree(prng_data); |
| return ret; |
| } |
| |
| |
| static void prng_sha512_deinstantiate(void) |
| { |
| pr_debug("The prng module stopped after running in SHA-512 mode\n"); |
| kfree_sensitive(prng_data); |
| } |
| |
| |
| static int prng_sha512_reseed(void) |
| { |
| int ret, seedlen; |
| u8 seed[64]; |
| |
| /* We need at least 256 bits of fresh entropy for reseeding */ |
| if (trng_available) { |
| /* trng produces 256 bits entropy in 32 bytes */ |
| seedlen = 32; |
| cpacf_trng(NULL, 0, seed, seedlen); |
| } else { |
| /* generate_entropy() produces 256 bits entropy in 64 bytes */ |
| seedlen = 64; |
| ret = generate_entropy(seed, seedlen); |
| if (ret != sizeof(seed)) |
| return ret; |
| } |
| |
| /* do a reseed of the prno drng with this bytestring */ |
| cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, |
| &prng_data->prnows, NULL, 0, seed, seedlen); |
| memzero_explicit(seed, sizeof(seed)); |
| |
| return 0; |
| } |
| |
| |
| static int prng_sha512_generate(u8 *buf, size_t nbytes) |
| { |
| int ret; |
| |
| /* reseed needed ? */ |
| if (prng_data->prnows.reseed_counter > prng_reseed_limit) { |
| ret = prng_sha512_reseed(); |
| if (ret) |
| return ret; |
| } |
| |
| /* PRNO generate */ |
| cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, |
| &prng_data->prnows, buf, nbytes, NULL, 0); |
| |
| /* FIPS 140-2 Conditional Self Test */ |
| if (fips_enabled) { |
| if (!memcmp(prng_data->prev, buf, nbytes)) { |
| prng_errorflag = PRNG_GEN_FAILED; |
| return -EILSEQ; |
| } |
| memcpy(prng_data->prev, buf, nbytes); |
| } |
| |
| return nbytes; |
| } |
| |
| |
| /*** file io functions ***/ |
| |
| static int prng_open(struct inode *inode, struct file *file) |
| { |
| return nonseekable_open(inode, file); |
| } |
| |
| |
| static ssize_t prng_tdes_read(struct file *file, char __user *ubuf, |
| size_t nbytes, loff_t *ppos) |
| { |
| int chunk, n, ret = 0; |
| |
| /* lock prng_data struct */ |
| if (mutex_lock_interruptible(&prng_data->mutex)) |
| return -ERESTARTSYS; |
| |
| while (nbytes) { |
| if (need_resched()) { |
| if (signal_pending(current)) { |
| if (ret == 0) |
| ret = -ERESTARTSYS; |
| break; |
| } |
| /* give mutex free before calling schedule() */ |
| mutex_unlock(&prng_data->mutex); |
| schedule(); |
| /* occupy mutex again */ |
| if (mutex_lock_interruptible(&prng_data->mutex)) { |
| if (ret == 0) |
| ret = -ERESTARTSYS; |
| return ret; |
| } |
| } |
| |
| /* |
| * we lose some random bytes if an attacker issues |
| * reads < 8 bytes, but we don't care |
| */ |
| chunk = min_t(int, nbytes, prng_chunk_size); |
| |
| /* PRNG only likes multiples of 8 bytes */ |
| n = (chunk + 7) & -8; |
| |
| if (prng_data->prngws.reseed_counter > prng_reseed_limit) |
| prng_tdes_seed(8); |
| |
| /* if the CPU supports PRNG stckf is present too */ |
| *((unsigned long long *)prng_data->buf) = get_tod_clock_fast(); |
| |
| /* |
| * Beside the STCKF the input for the TDES-EDE is the output |
| * of the last operation. We differ here from X9.17 since we |
| * only store one timestamp into the buffer. Padding the whole |
| * buffer with timestamps does not improve security, since |
| * successive stckf have nearly constant offsets. |
| * If an attacker knows the first timestamp it would be |
| * trivial to guess the additional values. One timestamp |
| * is therefore enough and still guarantees unique input values. |
| * |
| * Note: you can still get strict X9.17 conformity by setting |
| * prng_chunk_size to 8 bytes. |
| */ |
| cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block, |
| prng_data->buf, prng_data->buf, n); |
| |
| prng_data->prngws.byte_counter += n; |
| prng_data->prngws.reseed_counter += n; |
| |
| if (copy_to_user(ubuf, prng_data->buf, chunk)) { |
| ret = -EFAULT; |
| break; |
| } |
| |
| nbytes -= chunk; |
| ret += chunk; |
| ubuf += chunk; |
| } |
| |
| /* unlock prng_data struct */ |
| mutex_unlock(&prng_data->mutex); |
| |
| return ret; |
| } |
| |
| |
| static ssize_t prng_sha512_read(struct file *file, char __user *ubuf, |
| size_t nbytes, loff_t *ppos) |
| { |
| int n, ret = 0; |
| u8 *p; |
| |
| /* if errorflag is set do nothing and return 'broken pipe' */ |
| if (prng_errorflag) |
| return -EPIPE; |
| |
| /* lock prng_data struct */ |
| if (mutex_lock_interruptible(&prng_data->mutex)) |
| return -ERESTARTSYS; |
| |
| while (nbytes) { |
| if (need_resched()) { |
| if (signal_pending(current)) { |
| if (ret == 0) |
| ret = -ERESTARTSYS; |
| break; |
| } |
| /* give mutex free before calling schedule() */ |
| mutex_unlock(&prng_data->mutex); |
| schedule(); |
| /* occopy mutex again */ |
| if (mutex_lock_interruptible(&prng_data->mutex)) { |
| if (ret == 0) |
| ret = -ERESTARTSYS; |
| return ret; |
| } |
| } |
| if (prng_data->rest) { |
| /* push left over random bytes from the previous read */ |
| p = prng_data->buf + prng_chunk_size - prng_data->rest; |
| n = (nbytes < prng_data->rest) ? |
| nbytes : prng_data->rest; |
| prng_data->rest -= n; |
| } else { |
| /* generate one chunk of random bytes into read buf */ |
| p = prng_data->buf; |
| n = prng_sha512_generate(p, prng_chunk_size); |
| if (n < 0) { |
| ret = n; |
| break; |
| } |
| if (nbytes < prng_chunk_size) { |
| n = nbytes; |
| prng_data->rest = prng_chunk_size - n; |
| } else { |
| n = prng_chunk_size; |
| prng_data->rest = 0; |
| } |
| } |
| if (copy_to_user(ubuf, p, n)) { |
| ret = -EFAULT; |
| break; |
| } |
| memzero_explicit(p, n); |
| ubuf += n; |
| nbytes -= n; |
| ret += n; |
| } |
| |
| /* unlock prng_data struct */ |
| mutex_unlock(&prng_data->mutex); |
| |
| return ret; |
| } |
| |
| |
| /*** sysfs stuff ***/ |
| |
| static const struct file_operations prng_sha512_fops = { |
| .owner = THIS_MODULE, |
| .open = &prng_open, |
| .release = NULL, |
| .read = &prng_sha512_read, |
| .llseek = noop_llseek, |
| }; |
| static const struct file_operations prng_tdes_fops = { |
| .owner = THIS_MODULE, |
| .open = &prng_open, |
| .release = NULL, |
| .read = &prng_tdes_read, |
| .llseek = noop_llseek, |
| }; |
| |
| /* chunksize attribute (ro) */ |
| static ssize_t prng_chunksize_show(struct device *dev, |
| struct device_attribute *attr, |
| char *buf) |
| { |
| return scnprintf(buf, PAGE_SIZE, "%u\n", prng_chunk_size); |
| } |
| static DEVICE_ATTR(chunksize, 0444, prng_chunksize_show, NULL); |
| |
| /* counter attribute (ro) */ |
| static ssize_t prng_counter_show(struct device *dev, |
| struct device_attribute *attr, |
| char *buf) |
| { |
| u64 counter; |
| |
| if (mutex_lock_interruptible(&prng_data->mutex)) |
| return -ERESTARTSYS; |
| if (prng_mode == PRNG_MODE_SHA512) |
| counter = prng_data->prnows.stream_bytes; |
| else |
| counter = prng_data->prngws.byte_counter; |
| mutex_unlock(&prng_data->mutex); |
| |
| return scnprintf(buf, PAGE_SIZE, "%llu\n", counter); |
| } |
| static DEVICE_ATTR(byte_counter, 0444, prng_counter_show, NULL); |
| |
| /* errorflag attribute (ro) */ |
| static ssize_t prng_errorflag_show(struct device *dev, |
| struct device_attribute *attr, |
| char *buf) |
| { |
| return scnprintf(buf, PAGE_SIZE, "%d\n", prng_errorflag); |
| } |
| static DEVICE_ATTR(errorflag, 0444, prng_errorflag_show, NULL); |
| |
| /* mode attribute (ro) */ |
| static ssize_t prng_mode_show(struct device *dev, |
| struct device_attribute *attr, |
| char *buf) |
| { |
| if (prng_mode == PRNG_MODE_TDES) |
| return scnprintf(buf, PAGE_SIZE, "TDES\n"); |
| else |
| return scnprintf(buf, PAGE_SIZE, "SHA512\n"); |
| } |
| static DEVICE_ATTR(mode, 0444, prng_mode_show, NULL); |
| |
| /* reseed attribute (w) */ |
| static ssize_t prng_reseed_store(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, size_t count) |
| { |
| if (mutex_lock_interruptible(&prng_data->mutex)) |
| return -ERESTARTSYS; |
| prng_sha512_reseed(); |
| mutex_unlock(&prng_data->mutex); |
| |
| return count; |
| } |
| static DEVICE_ATTR(reseed, 0200, NULL, prng_reseed_store); |
| |
| /* reseed limit attribute (rw) */ |
| static ssize_t prng_reseed_limit_show(struct device *dev, |
| struct device_attribute *attr, |
| char *buf) |
| { |
| return scnprintf(buf, PAGE_SIZE, "%u\n", prng_reseed_limit); |
| } |
| static ssize_t prng_reseed_limit_store(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, size_t count) |
| { |
| unsigned limit; |
| |
| if (sscanf(buf, "%u\n", &limit) != 1) |
| return -EINVAL; |
| |
| if (prng_mode == PRNG_MODE_SHA512) { |
| if (limit < PRNG_RESEED_LIMIT_SHA512_LOWER) |
| return -EINVAL; |
| } else { |
| if (limit < PRNG_RESEED_LIMIT_TDES_LOWER) |
| return -EINVAL; |
| } |
| |
| prng_reseed_limit = limit; |
| |
| return count; |
| } |
| static DEVICE_ATTR(reseed_limit, 0644, |
| prng_reseed_limit_show, prng_reseed_limit_store); |
| |
| /* strength attribute (ro) */ |
| static ssize_t prng_strength_show(struct device *dev, |
| struct device_attribute *attr, |
| char *buf) |
| { |
| return scnprintf(buf, PAGE_SIZE, "256\n"); |
| } |
| static DEVICE_ATTR(strength, 0444, prng_strength_show, NULL); |
| |
| static struct attribute *prng_sha512_dev_attrs[] = { |
| &dev_attr_errorflag.attr, |
| &dev_attr_chunksize.attr, |
| &dev_attr_byte_counter.attr, |
| &dev_attr_mode.attr, |
| &dev_attr_reseed.attr, |
| &dev_attr_reseed_limit.attr, |
| &dev_attr_strength.attr, |
| NULL |
| }; |
| ATTRIBUTE_GROUPS(prng_sha512_dev); |
| |
| static struct attribute *prng_tdes_dev_attrs[] = { |
| &dev_attr_chunksize.attr, |
| &dev_attr_byte_counter.attr, |
| &dev_attr_mode.attr, |
| NULL |
| }; |
| ATTRIBUTE_GROUPS(prng_tdes_dev); |
| |
| static struct miscdevice prng_sha512_dev = { |
| .name = "prandom", |
| .minor = MISC_DYNAMIC_MINOR, |
| .mode = 0644, |
| .fops = &prng_sha512_fops, |
| .groups = prng_sha512_dev_groups, |
| }; |
| |
| static struct miscdevice prng_tdes_dev = { |
| .name = "prandom", |
| .minor = MISC_DYNAMIC_MINOR, |
| .mode = 0644, |
| .fops = &prng_tdes_fops, |
| .groups = prng_tdes_dev_groups, |
| }; |
| |
| |
| /*** module init and exit ***/ |
| |
| static int __init prng_init(void) |
| { |
| int ret; |
| |
| /* check if the CPU has a PRNG */ |
| if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG)) |
| return -ENODEV; |
| |
| /* check if TRNG subfunction is available */ |
| if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG)) |
| trng_available = true; |
| |
| /* choose prng mode */ |
| if (prng_mode != PRNG_MODE_TDES) { |
| /* check for MSA5 support for PRNO operations */ |
| if (!cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN)) { |
| if (prng_mode == PRNG_MODE_SHA512) { |
| pr_err("The prng module cannot " |
| "start in SHA-512 mode\n"); |
| return -ENODEV; |
| } |
| prng_mode = PRNG_MODE_TDES; |
| } else |
| prng_mode = PRNG_MODE_SHA512; |
| } |
| |
| if (prng_mode == PRNG_MODE_SHA512) { |
| |
| /* SHA512 mode */ |
| |
| if (prng_chunk_size < PRNG_CHUNKSIZE_SHA512_MIN |
| || prng_chunk_size > PRNG_CHUNKSIZE_SHA512_MAX) |
| return -EINVAL; |
| prng_chunk_size = (prng_chunk_size + 0x3f) & ~0x3f; |
| |
| if (prng_reseed_limit == 0) |
| prng_reseed_limit = PRNG_RESEED_LIMIT_SHA512; |
| else if (prng_reseed_limit < PRNG_RESEED_LIMIT_SHA512_LOWER) |
| return -EINVAL; |
| |
| ret = prng_sha512_instantiate(); |
| if (ret) |
| goto out; |
| |
| ret = misc_register(&prng_sha512_dev); |
| if (ret) { |
| prng_sha512_deinstantiate(); |
| goto out; |
| } |
| |
| } else { |
| |
| /* TDES mode */ |
| |
| if (prng_chunk_size < PRNG_CHUNKSIZE_TDES_MIN |
| || prng_chunk_size > PRNG_CHUNKSIZE_TDES_MAX) |
| return -EINVAL; |
| prng_chunk_size = (prng_chunk_size + 0x07) & ~0x07; |
| |
| if (prng_reseed_limit == 0) |
| prng_reseed_limit = PRNG_RESEED_LIMIT_TDES; |
| else if (prng_reseed_limit < PRNG_RESEED_LIMIT_TDES_LOWER) |
| return -EINVAL; |
| |
| ret = prng_tdes_instantiate(); |
| if (ret) |
| goto out; |
| |
| ret = misc_register(&prng_tdes_dev); |
| if (ret) { |
| prng_tdes_deinstantiate(); |
| goto out; |
| } |
| } |
| |
| out: |
| return ret; |
| } |
| |
| |
| static void __exit prng_exit(void) |
| { |
| if (prng_mode == PRNG_MODE_SHA512) { |
| misc_deregister(&prng_sha512_dev); |
| prng_sha512_deinstantiate(); |
| } else { |
| misc_deregister(&prng_tdes_dev); |
| prng_tdes_deinstantiate(); |
| } |
| } |
| |
| module_cpu_feature_match(MSA, prng_init); |
| module_exit(prng_exit); |