Mercurial > hg > nginx
view src/core/ngx_md5.c @ 7281:bd6563e81cea
Limit req: improved handling of negative times.
Negative times can appear since workers only update time on an event
loop iteration start. If a worker was blocked for a long time during
an event loop iteration, it is possible that another worker already
updated the time stored in the node. As such, time since last update
of the node (ms) will be negative.
Previous code used ngx_abs(ms) in the calculations. That is, negative
times were effectively treated as positive ones. As a result, it was
not possible to maintain high request rates, where the same node can be
updated multiple times from during an event loop iteration.
In particular, this affected setups with many SSL handshakes, see
http://mailman.nginx.org/pipermail/nginx/2018-May/056291.html.
Fix is to only update the last update time stored in the node if the
new time is larger than previously stored one. If a future time is
stored in the node, we preserve this time as is.
To prevent breaking things on platforms without monotonic time available
if system time is updated backwards, a safety limit of 60 seconds is
used. If the time stored in the node is more than 60 seconds in the future,
we assume that the time was changed backwards and update lr->last
to the current time.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 30 May 2018 15:40:34 +0300 |
parents | 9eefb38f0005 |
children | 0086f8da5d8d |
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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 */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_md5.h> 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; }