/* * Copyright (c) 1999-2006 Apple Computer, Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define RANDOM_MAJOR -1 /* let the kernel pick the device number */ d_ioctl_t random_ioctl; /* * A struct describing which functions will get invoked for certain * actions. */ static struct cdevsw random_cdevsw = { random_open, /* open */ random_close, /* close */ random_read, /* read */ random_write, /* write */ random_ioctl, /* ioctl */ (stop_fcn_t *)nulldev, /* stop */ (reset_fcn_t *)nulldev, /* reset */ NULL, /* tty's */ eno_select, /* select */ eno_mmap, /* mmap */ eno_strat, /* strategy */ eno_getc, /* getc */ eno_putc, /* putc */ 0 /* type */ }; /* Used to detect whether we've already been initialized */ static int gRandomInstalled = 0; static PrngRef gPrngRef; static int gRandomError = 1; static lck_grp_t *gYarrowGrp; static lck_attr_t *gYarrowAttr; static lck_grp_attr_t *gYarrowGrpAttr; static lck_mtx_t *gYarrowMutex = 0; void CheckReseed(void); #define RESEED_TICKS 50 /* how long a reseed operation can take */ enum {kBSizeInBits = 160}; // MUST be a multiple of 32!!! enum {kBSizeInBytes = kBSizeInBits / 8}; typedef u_int32_t BlockWord; enum {kWordSizeInBits = 32}; enum {kBSize = 5}; typedef BlockWord Block[kBSize]; /* define prototypes to keep the compiler happy... */ void add_blocks(Block a, Block b, BlockWord carry); void fips_initialize(void); void random_block(Block b); u_int32_t CalculateCRC(u_int8_t* buffer, size_t length); /* * Get 120 bits from yarrow */ /* * add block b to block a */ void add_blocks(Block a, Block b, BlockWord carry) { int i = kBSize; while (--i >= 0) { u_int64_t c = (u_int64_t)carry + (u_int64_t)a[i] + (u_int64_t)b[i]; a[i] = c & ((1LL << kWordSizeInBits) - 1); carry = c >> kWordSizeInBits; } } struct sha1_ctxt g_sha1_ctx; char zeros[(512 - kBSizeInBits) / 8]; Block g_xkey; Block g_random_data; int g_bytes_used; unsigned char g_SelfTestInitialized = 0; u_int32_t gLastBlockChecksum; static const u_int32_t g_crc_table[] = { 0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F, 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9, 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D, }; /* * Setup for fips compliance */ /* * calculate a crc-32 checksum */ u_int32_t CalculateCRC(u_int8_t* buffer, size_t length) { u_int32_t crc = 0; size_t i; for (i = 0; i < length; ++i) { u_int32_t temp = (crc ^ ((u_int32_t) buffer[i])) & 0xFF; crc = (crc >> 8) ^ g_crc_table[temp]; } return crc; } /* * get a random block of data per fips 186-2 */ void random_block(Block b) { int repeatCount = 0; do { // do one iteration Block xSeed; prngOutput (gPrngRef, (BYTE*) &xSeed, sizeof (xSeed)); // add the seed to the previous value of g_xkey add_blocks (g_xkey, xSeed, 0); // compute "G" SHA1Update (&g_sha1_ctx, (const u_int8_t *) &g_xkey, sizeof (g_xkey)); // add zeros to fill the internal SHA-1 buffer SHA1Update (&g_sha1_ctx, (const u_int8_t *)zeros, sizeof (zeros)); // write the resulting block memmove(b, g_sha1_ctx.h.b8, sizeof (Block)); // calculate the CRC-32 of the block u_int32_t new_crc = CalculateCRC(g_sha1_ctx.h.b8, sizeof (Block)); // make sure we don't repeat int cmp = new_crc == gLastBlockChecksum; gLastBlockChecksum = new_crc; if (!g_SelfTestInitialized) { g_SelfTestInitialized = 1; return; } else if (!cmp) { return; } repeatCount += 1; // fix up the next value of g_xkey add_blocks (g_xkey, b, 1); } while (repeatCount < 2); /* * If we got here, three sucessive checksums of the random number * generator have been the same. Since the odds of this happening are * 1 in 18,446,744,073,709,551,616, (1 in 18 quintillion) one of the following has * most likely happened: * * 1: There is a significant bug in this code. * 2: There has been a massive system failure. * 3: The universe has ceased to exist. * * There is no good way to recover from any of these cases. We * therefore panic. */ panic("FIPS random self-test failed."); } /* *Initialize ONLY the Yarrow generator. */ void PreliminarySetup(void) { prng_error_status perr; /* create a Yarrow object */ perr = prngInitialize(&gPrngRef); if (perr != 0) { printf ("Couldn't initialize Yarrow, /dev/random will not work.\n"); return; } /* clear the error flag, reads and write should then work */ gRandomError = 0; { struct timeval tt; char buffer [16]; /* get a little non-deterministic data as an initial seed. */ microtime(&tt); /* * So how much of the system clock is entropic? * It's hard to say, but assume that at least the * least significant byte of a 64 bit structure * is entropic. It's probably more, how can you figure * the exact time the user turned the computer on, for example. */ perr = prngInput(gPrngRef, (BYTE*) &tt, sizeof (tt), SYSTEM_SOURCE, 8); if (perr != 0) { /* an error, complain */ printf ("Couldn't seed Yarrow.\n"); return; } /* turn the data around */ perr = prngOutput(gPrngRef, (BYTE*) buffer, sizeof (buffer)); /* and scramble it some more */ perr = prngForceReseed(gPrngRef, RESEED_TICKS); } /* make a mutex to control access */ gYarrowGrpAttr = lck_grp_attr_alloc_init(); gYarrowGrp = lck_grp_alloc_init("random", gYarrowGrpAttr); gYarrowAttr = lck_attr_alloc_init(); gYarrowMutex = lck_mtx_alloc_init(gYarrowGrp, gYarrowAttr); fips_initialize (); } void fips_initialize(void) { /* Read the initial value of g_xkey from yarrow */ prngOutput (gPrngRef, (BYTE*) &g_xkey, sizeof (g_xkey)); /* initialize our SHA1 generator */ SHA1Init (&g_sha1_ctx); /* other initializations */ memset (zeros, 0, sizeof (zeros)); g_bytes_used = 0; random_block(g_random_data); } /* * Called to initialize our device, * and to register ourselves with devfs */ void random_init(void) { int ret; if (gRandomInstalled) return; /* install us in the file system */ gRandomInstalled = 1; #ifndef ARM_BOARD_CONFIG_S5L8900XFPGA_1136JFS /* setup yarrow and the mutex */ PreliminarySetup(); #endif ret = cdevsw_add(RANDOM_MAJOR, &random_cdevsw); if (ret < 0) { printf("random_init: failed to allocate a major number!\n"); gRandomInstalled = 0; return; } devfs_make_node(makedev (ret, 0), DEVFS_CHAR, UID_ROOT, GID_WHEEL, 0666, "random", 0); /* * also make urandom * (which is exactly the same thing in our context) */ devfs_make_node(makedev (ret, 1), DEVFS_CHAR, UID_ROOT, GID_WHEEL, 0666, "urandom", 0); } int random_ioctl( __unused dev_t dev, u_long cmd, __unused caddr_t data, __unused int flag, __unused struct proc *p ) { switch (cmd) { case FIONBIO: case FIOASYNC: break; default: return ENODEV; } return (0); } /* * Open the device. Make sure init happened, and make sure the caller is * authorized. */ int random_open(__unused dev_t dev, int flags, __unused int devtype, __unused struct proc *p) { if (gRandomError != 0) { /* forget it, yarrow didn't come up */ return (ENOTSUP); } /* * if we are being opened for write, * make sure that we have privledges do so */ if (flags & FWRITE) { if (securelevel >= 2) return (EPERM); #ifndef __APPLE__ if ((securelevel >= 1) && proc_suser(p)) return (EPERM); #endif /* !__APPLE__ */ } return (0); } /* * close the device. */ int random_close(__unused dev_t dev, __unused int flags, __unused int mode, __unused struct proc *p) { return (0); } /* * Get entropic data from the Security Server, and use it to reseed the * prng. */ int random_write (__unused dev_t dev, struct uio *uio, __unused int ioflag) { int retCode = 0; char rdBuffer[256]; if (gRandomError != 0) { return (ENOTSUP); } /* get control of the Yarrow instance, Yarrow is NOT thread safe */ lck_mtx_lock(gYarrowMutex); /* Security server is sending us entropy */ while (uio_resid(uio) > 0 && retCode == 0) { /* get the user's data */ // LP64todo - fix this! uio_resid may be 64-bit value int bytesToInput = min(uio_resid(uio), sizeof (rdBuffer)); retCode = uiomove(rdBuffer, bytesToInput, uio); if (retCode != 0) goto /*ugh*/ error_exit; /* put it in Yarrow */ if (prngInput(gPrngRef, (BYTE*) rdBuffer, bytesToInput, SYSTEM_SOURCE, bytesToInput * 8) != 0) { retCode = EIO; goto error_exit; } } /* force a reseed */ if (prngForceReseed(gPrngRef, RESEED_TICKS) != 0) { retCode = EIO; goto error_exit; } /* retCode should be 0 at this point */ error_exit: /* do this to make sure the mutex unlocks. */ lck_mtx_unlock(gYarrowMutex); return (retCode); } /* * return data to the caller. Results unpredictable. */ int random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag) { int retCode = 0; if (gRandomError != 0) return (ENOTSUP); /* lock down the mutex */ lck_mtx_lock(gYarrowMutex); CheckReseed(); int bytes_remaining = uio_resid(uio); while (bytes_remaining > 0 && retCode == 0) { /* get the user's data */ int bytes_to_read = 0; int bytes_available = kBSizeInBytes - g_bytes_used; if (bytes_available == 0) { random_block(g_random_data); g_bytes_used = 0; bytes_available = kBSizeInBytes; } bytes_to_read = min (bytes_remaining, bytes_available); retCode = uiomove(((caddr_t)g_random_data)+ g_bytes_used, bytes_to_read, uio); g_bytes_used += bytes_to_read; if (retCode != 0) goto error_exit; bytes_remaining = uio_resid(uio); } retCode = 0; error_exit: lck_mtx_unlock(gYarrowMutex); return retCode; } /* export good random numbers to the rest of the kernel */ void read_random(void* buffer, u_int numbytes) { if (gYarrowMutex == 0) { /* are we initialized? */ #ifndef ARM_BOARD_CONFIG_S5L8900XFPGA_1136JFS PreliminarySetup (); #endif } lck_mtx_lock(gYarrowMutex); CheckReseed(); int bytes_read = 0; int bytes_remaining = numbytes; while (bytes_remaining > 0) { int bytes_to_read = min(bytes_remaining, kBSizeInBytes - g_bytes_used); if (bytes_to_read == 0) { random_block(g_random_data); g_bytes_used = 0; bytes_to_read = min(bytes_remaining, kBSizeInBytes); } memmove ((u_int8_t*) buffer + bytes_read, ((u_int8_t*)g_random_data)+ g_bytes_used, bytes_to_read); g_bytes_used += bytes_to_read; bytes_read += bytes_to_read; bytes_remaining -= bytes_to_read; } lck_mtx_unlock(gYarrowMutex); } /* * Return an unsigned long pseudo-random number. */ u_long RandomULong(void) { u_long buf; read_random(&buf, sizeof (buf)); return (buf); } void CheckReseed(void) { }