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view src/os/unix/ngx_sunpro_amd64.il @ 7386:9200b41db765 stable-1.14
HTTP/2: limit the number of idle state switches.
An attack that continuously switches HTTP/2 connection between
idle and active states can result in excessive CPU usage.
This is because when a connection switches to the idle state,
all of its memory pool caches are freed.
This change limits the maximum allowed number of idle state
switches to 10 * http2_max_requests (i.e., 10000 by default).
This limits possible CPU usage in one connection, and also
imposes a limit on the maximum lifetime of a connection.
Initially reported by Gal Goldshtein from F5 Networks.
author | Ruslan Ermilov <ru@nginx.com> |
---|---|
date | Tue, 06 Nov 2018 16:29:49 +0300 |
parents | 2cd019520210 |
children |
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/ / Copyright (C) Igor Sysoev / Copyright (C) Nginx, Inc. / / ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock, / ngx_atomic_uint_t old, ngx_atomic_uint_t set); / / the arguments are passed in %rdi, %rsi, %rdx / the result is returned in the %rax .inline ngx_atomic_cmp_set,0 movq %rsi, %rax lock cmpxchgq %rdx, (%rdi) setz %al movzbq %al, %rax .end / ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value, / ngx_atomic_int_t add); / / the arguments are passed in %rdi, %rsi / the result is returned in the %rax .inline ngx_atomic_fetch_add,0 movq %rsi, %rax lock xaddq %rax, (%rdi) .end / ngx_cpu_pause() / / the "rep; nop" is used instead of "pause" to avoid the "[ PAUSE ]" hardware / capability added by linker because Solaris/amd64 does not know about it: / / ld.so.1: nginx: fatal: hardware capability unsupported: 0x2000 [ PAUSE ] .inline ngx_cpu_pause,0 rep; nop .end