Mercurial > hg > nginx
view src/core/ngx_md5.c @ 4576:876e6b0814a5
Fixed signed integer overflows in timer code (ticket #145).
Integer overflow is undefined behaviour in C and this indeed caused
problems on Solaris/SPARC (at least in some cases). Fix is to
subtract unsigned integers instead, and then cast result to a signed
one, which is implementation-defined behaviour and used to work.
Strictly speaking, we should compare (unsigned) result with the maximum
value of the corresponding signed integer type instead, this will be
defined behaviour. This will require much more changes though, and
considered to be overkill for now.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Fri, 06 Apr 2012 23:46:09 +0000 |
parents | 21167183825d |
children | 9eefb38f0005 |
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/* * An internal implementation, based on Alexander Peslyak's * public domain implementation: * http://openwall.info/wiki/people/solar/software/public-domain-source-code/md5 * It is not expected to be optimal and is used only * if no MD5 implementation was found in system. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_md5.h> #if !(NGX_HAVE_MD5) static const u_char *ngx_md5_body(ngx_md5_t *ctx, const u_char *data, size_t size); void ngx_md5_init(ngx_md5_t *ctx) { ctx->a = 0x67452301; ctx->b = 0xefcdab89; ctx->c = 0x98badcfe; ctx->d = 0x10325476; ctx->bytes = 0; } void ngx_md5_update(ngx_md5_t *ctx, const void *data, size_t size) { size_t used, free; used = (size_t) (ctx->bytes & 0x3f); ctx->bytes += size; if (used) { free = 64 - used; if (size < free) { ngx_memcpy(&ctx->buffer[used], data, size); return; } ngx_memcpy(&ctx->buffer[used], data, free); data = (u_char *) data + free; size -= free; (void) ngx_md5_body(ctx, ctx->buffer, 64); } if (size >= 64) { data = ngx_md5_body(ctx, data, size & ~(size_t) 0x3f); size &= 0x3f; } ngx_memcpy(ctx->buffer, data, size); } void ngx_md5_final(u_char result[16], ngx_md5_t *ctx) { size_t used, free; used = (size_t) (ctx->bytes & 0x3f); ctx->buffer[used++] = 0x80; free = 64 - used; if (free < 8) { ngx_memzero(&ctx->buffer[used], free); (void) ngx_md5_body(ctx, ctx->buffer, 64); used = 0; free = 64; } ngx_memzero(&ctx->buffer[used], free - 8); ctx->bytes <<= 3; ctx->buffer[56] = (u_char) ctx->bytes; ctx->buffer[57] = (u_char) (ctx->bytes >> 8); ctx->buffer[58] = (u_char) (ctx->bytes >> 16); ctx->buffer[59] = (u_char) (ctx->bytes >> 24); ctx->buffer[60] = (u_char) (ctx->bytes >> 32); ctx->buffer[61] = (u_char) (ctx->bytes >> 40); ctx->buffer[62] = (u_char) (ctx->bytes >> 48); ctx->buffer[63] = (u_char) (ctx->bytes >> 56); (void) ngx_md5_body(ctx, ctx->buffer, 64); result[0] = (u_char) ctx->a; result[1] = (u_char) (ctx->a >> 8); result[2] = (u_char) (ctx->a >> 16); result[3] = (u_char) (ctx->a >> 24); result[4] = (u_char) ctx->b; result[5] = (u_char) (ctx->b >> 8); result[6] = (u_char) (ctx->b >> 16); result[7] = (u_char) (ctx->b >> 24); result[8] = (u_char) ctx->c; result[9] = (u_char) (ctx->c >> 8); result[10] = (u_char) (ctx->c >> 16); result[11] = (u_char) (ctx->c >> 24); result[12] = (u_char) ctx->d; result[13] = (u_char) (ctx->d >> 8); result[14] = (u_char) (ctx->d >> 16); result[15] = (u_char) (ctx->d >> 24); ngx_memzero(ctx, sizeof(*ctx)); } /* * The basic MD5 functions. * * F and G are optimized compared to their RFC 1321 definitions for * architectures that lack an AND-NOT instruction, just like in * Colin Plumb's implementation. */ #define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z)))) #define G(x, y, z) ((y) ^ ((z) & ((x) ^ (y)))) #define H(x, y, z) ((x) ^ (y) ^ (z)) #define I(x, y, z) ((y) ^ ((x) | ~(z))) /* * The MD5 transformation for all four rounds. */ #define STEP(f, a, b, c, d, x, t, s) \ (a) += f((b), (c), (d)) + (x) + (t); \ (a) = (((a) << (s)) | (((a) & 0xffffffff) >> (32 - (s)))); \ (a) += (b) /* * SET() reads 4 input bytes in little-endian byte order and stores them * in a properly aligned word in host byte order. * * The check for little-endian architectures that tolerate unaligned * memory accesses is just an optimization. Nothing will break if it * does not work. */ #if (NGX_HAVE_LITTLE_ENDIAN && NGX_HAVE_NONALIGNED) #define SET(n) (*(uint32_t *) &p[n * 4]) #define GET(n) (*(uint32_t *) &p[n * 4]) #else #define SET(n) \ (block[n] = \ (uint32_t) p[n * 4] | \ ((uint32_t) p[n * 4 + 1] << 8) | \ ((uint32_t) p[n * 4 + 2] << 16) | \ ((uint32_t) p[n * 4 + 3] << 24)) #define GET(n) block[n] #endif /* * This processes one or more 64-byte data blocks, but does not update * the bit counters. There are no alignment requirements. */ static const u_char * ngx_md5_body(ngx_md5_t *ctx, const u_char *data, size_t size) { uint32_t a, b, c, d; uint32_t saved_a, saved_b, saved_c, saved_d; const u_char *p; #if !(NGX_HAVE_LITTLE_ENDIAN && NGX_HAVE_NONALIGNED) uint32_t block[16]; #endif p = data; a = ctx->a; b = ctx->b; c = ctx->c; d = ctx->d; do { saved_a = a; saved_b = b; saved_c = c; saved_d = d; /* Round 1 */ STEP(F, a, b, c, d, SET(0), 0xd76aa478, 7); STEP(F, d, a, b, c, SET(1), 0xe8c7b756, 12); STEP(F, c, d, a, b, SET(2), 0x242070db, 17); STEP(F, b, c, d, a, SET(3), 0xc1bdceee, 22); STEP(F, a, b, c, d, SET(4), 0xf57c0faf, 7); STEP(F, d, a, b, c, SET(5), 0x4787c62a, 12); STEP(F, c, d, a, b, SET(6), 0xa8304613, 17); STEP(F, b, c, d, a, SET(7), 0xfd469501, 22); STEP(F, a, b, c, d, SET(8), 0x698098d8, 7); STEP(F, d, a, b, c, SET(9), 0x8b44f7af, 12); STEP(F, c, d, a, b, SET(10), 0xffff5bb1, 17); STEP(F, b, c, d, a, SET(11), 0x895cd7be, 22); STEP(F, a, b, c, d, SET(12), 0x6b901122, 7); STEP(F, d, a, b, c, SET(13), 0xfd987193, 12); STEP(F, c, d, a, b, SET(14), 0xa679438e, 17); STEP(F, b, c, d, a, SET(15), 0x49b40821, 22); /* Round 2 */ STEP(G, a, b, c, d, GET(1), 0xf61e2562, 5); STEP(G, d, a, b, c, GET(6), 0xc040b340, 9); STEP(G, c, d, a, b, GET(11), 0x265e5a51, 14); STEP(G, b, c, d, a, GET(0), 0xe9b6c7aa, 20); STEP(G, a, b, c, d, GET(5), 0xd62f105d, 5); STEP(G, d, a, b, c, GET(10), 0x02441453, 9); STEP(G, c, d, a, b, GET(15), 0xd8a1e681, 14); STEP(G, b, c, d, a, GET(4), 0xe7d3fbc8, 20); STEP(G, a, b, c, d, GET(9), 0x21e1cde6, 5); STEP(G, d, a, b, c, GET(14), 0xc33707d6, 9); STEP(G, c, d, a, b, GET(3), 0xf4d50d87, 14); STEP(G, b, c, d, a, GET(8), 0x455a14ed, 20); STEP(G, a, b, c, d, GET(13), 0xa9e3e905, 5); STEP(G, d, a, b, c, GET(2), 0xfcefa3f8, 9); STEP(G, c, d, a, b, GET(7), 0x676f02d9, 14); STEP(G, b, c, d, a, GET(12), 0x8d2a4c8a, 20); /* Round 3 */ STEP(H, a, b, c, d, GET(5), 0xfffa3942, 4); STEP(H, d, a, b, c, GET(8), 0x8771f681, 11); STEP(H, c, d, a, b, GET(11), 0x6d9d6122, 16); STEP(H, b, c, d, a, GET(14), 0xfde5380c, 23); STEP(H, a, b, c, d, GET(1), 0xa4beea44, 4); STEP(H, d, a, b, c, GET(4), 0x4bdecfa9, 11); STEP(H, c, d, a, b, GET(7), 0xf6bb4b60, 16); STEP(H, b, c, d, a, GET(10), 0xbebfbc70, 23); STEP(H, a, b, c, d, GET(13), 0x289b7ec6, 4); STEP(H, d, a, b, c, GET(0), 0xeaa127fa, 11); STEP(H, c, d, a, b, GET(3), 0xd4ef3085, 16); STEP(H, b, c, d, a, GET(6), 0x04881d05, 23); STEP(H, a, b, c, d, GET(9), 0xd9d4d039, 4); STEP(H, d, a, b, c, GET(12), 0xe6db99e5, 11); STEP(H, c, d, a, b, GET(15), 0x1fa27cf8, 16); STEP(H, b, c, d, a, GET(2), 0xc4ac5665, 23); /* Round 4 */ STEP(I, a, b, c, d, GET(0), 0xf4292244, 6); STEP(I, d, a, b, c, GET(7), 0x432aff97, 10); STEP(I, c, d, a, b, GET(14), 0xab9423a7, 15); STEP(I, b, c, d, a, GET(5), 0xfc93a039, 21); STEP(I, a, b, c, d, GET(12), 0x655b59c3, 6); STEP(I, d, a, b, c, GET(3), 0x8f0ccc92, 10); STEP(I, c, d, a, b, GET(10), 0xffeff47d, 15); STEP(I, b, c, d, a, GET(1), 0x85845dd1, 21); STEP(I, a, b, c, d, GET(8), 0x6fa87e4f, 6); STEP(I, d, a, b, c, GET(15), 0xfe2ce6e0, 10); STEP(I, c, d, a, b, GET(6), 0xa3014314, 15); STEP(I, b, c, d, a, GET(13), 0x4e0811a1, 21); STEP(I, a, b, c, d, GET(4), 0xf7537e82, 6); STEP(I, d, a, b, c, GET(11), 0xbd3af235, 10); STEP(I, c, d, a, b, GET(2), 0x2ad7d2bb, 15); STEP(I, b, c, d, a, GET(9), 0xeb86d391, 21); a += saved_a; b += saved_b; c += saved_c; d += saved_d; p += 64; } while (size -= 64); ctx->a = a; ctx->b = b; ctx->c = c; ctx->d = d; return p; } #endif