Mercurial > hg > nginx-quic
view src/core/ngx_cpuinfo.c @ 7977:7731c710796f
Memcached: protect from too long responses.
If a memcached response was followed by a correct trailer, and then
the NUL character followed by some extra data - this was accepted by
the trailer checking code. This in turn resulted in ctx->rest underflow
and caused negative size buffer on the next reading from the upstream,
followed by the "negative size buf in writer" alert.
Fix is to always check for too long responses, so a correct trailer cannot
be followed by extra data.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 06 Jul 2020 18:36:17 +0300 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #if (( __i386__ || __amd64__ ) && ( __GNUC__ || __INTEL_COMPILER )) static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf); #if ( __i386__ ) static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf) { /* * we could not use %ebx as output parameter if gcc builds PIC, * and we could not save %ebx on stack, because %esp is used, * when the -fomit-frame-pointer optimization is specified. */ __asm__ ( " mov %%ebx, %%esi; " " cpuid; " " mov %%eax, (%1); " " mov %%ebx, 4(%1); " " mov %%edx, 8(%1); " " mov %%ecx, 12(%1); " " mov %%esi, %%ebx; " : : "a" (i), "D" (buf) : "ecx", "edx", "esi", "memory" ); } #else /* __amd64__ */ static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf) { uint32_t eax, ebx, ecx, edx; __asm__ ( "cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (i) ); buf[0] = eax; buf[1] = ebx; buf[2] = edx; buf[3] = ecx; } #endif /* auto detect the L2 cache line size of modern and widespread CPUs */ void ngx_cpuinfo(void) { u_char *vendor; uint32_t vbuf[5], cpu[4], model; vbuf[0] = 0; vbuf[1] = 0; vbuf[2] = 0; vbuf[3] = 0; vbuf[4] = 0; ngx_cpuid(0, vbuf); vendor = (u_char *) &vbuf[1]; if (vbuf[0] == 0) { return; } ngx_cpuid(1, cpu); if (ngx_strcmp(vendor, "GenuineIntel") == 0) { switch ((cpu[0] & 0xf00) >> 8) { /* Pentium */ case 5: ngx_cacheline_size = 32; break; /* Pentium Pro, II, III */ case 6: ngx_cacheline_size = 32; model = ((cpu[0] & 0xf0000) >> 8) | (cpu[0] & 0xf0); if (model >= 0xd0) { /* Intel Core, Core 2, Atom */ ngx_cacheline_size = 64; } break; /* * Pentium 4, although its cache line size is 64 bytes, * it prefetches up to two cache lines during memory read */ case 15: ngx_cacheline_size = 128; break; } } else if (ngx_strcmp(vendor, "AuthenticAMD") == 0) { ngx_cacheline_size = 64; } } #else void ngx_cpuinfo(void) { } #endif