Mercurial > hg > nginx-quic
view src/http/ngx_http_busy_lock.c @ 6077:0395f788b080 stable-1.6
Resolver: fixed use-after-free memory access.
In 954867a2f0a6, we switched to using resolver node as the
timer event data, so make sure we do not free resolver node
memory until the corresponding timer is deleted.
author | Ruslan Ermilov <ru@nginx.com> |
---|---|
date | Thu, 20 Nov 2014 15:24:40 +0300 |
parents | 14411ee4d89f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> static int ngx_http_busy_lock_look_cacheable(ngx_http_busy_lock_t *bl, ngx_http_busy_lock_ctx_t *bc, int lock); int ngx_http_busy_lock(ngx_http_busy_lock_t *bl, ngx_http_busy_lock_ctx_t *bc) { if (bl->busy < bl->max_busy) { bl->busy++; if (bc->time) { bc->time = 0; bl->waiting--; } return NGX_OK; } if (bc->time) { if (bc->time < bl->timeout) { ngx_add_timer(bc->event, 1000); return NGX_AGAIN; } bl->waiting--; return NGX_DONE; } if (bl->timeout == 0) { return NGX_DONE; } if (bl->waiting < bl->max_waiting) { bl->waiting++; #if 0 ngx_add_timer(bc->event, 1000); bc->event->event_handler = bc->event_handler; #endif /* TODO: ngx_handle_level_read_event() */ return NGX_AGAIN; } return NGX_ERROR; } int ngx_http_busy_lock_cacheable(ngx_http_busy_lock_t *bl, ngx_http_busy_lock_ctx_t *bc, int lock) { int rc; rc = ngx_http_busy_lock_look_cacheable(bl, bc, lock); ngx_log_debug3(NGX_LOG_DEBUG_HTTP, bc->event->log, 0, "http busylock: %d w:%d mw::%d", rc, bl->waiting, bl->max_waiting); if (rc == NGX_OK) { /* no the same request, there's free slot */ return NGX_OK; } if (rc == NGX_ERROR && !lock) { /* no the same request, no free slot */ return NGX_OK; } /* rc == NGX_AGAIN: the same request */ if (bc->time) { if (bc->time < bl->timeout) { ngx_add_timer(bc->event, 1000); return NGX_AGAIN; } bl->waiting--; return NGX_DONE; } if (bl->timeout == 0) { return NGX_DONE; } if (bl->waiting < bl->max_waiting) { #if 0 bl->waiting++; ngx_add_timer(bc->event, 1000); bc->event->event_handler = bc->event_handler; #endif /* TODO: ngx_handle_level_read_event() */ return NGX_AGAIN; } return NGX_ERROR; } void ngx_http_busy_unlock(ngx_http_busy_lock_t *bl, ngx_http_busy_lock_ctx_t *bc) { if (bl == NULL) { return; } if (bl->md5) { bl->md5_mask[bc->slot / 8] &= ~(1 << (bc->slot & 7)); bl->cacheable--; } bl->busy--; } static int ngx_http_busy_lock_look_cacheable(ngx_http_busy_lock_t *bl, ngx_http_busy_lock_ctx_t *bc, int lock) { int i, b, cacheable, free; u_int mask; b = 0; cacheable = 0; free = -1; #if (NGX_SUPPRESS_WARN) mask = 0; #endif for (i = 0; i < bl->max_busy; i++) { if ((b & 7) == 0) { mask = bl->md5_mask[i / 8]; } if (mask & 1) { if (ngx_memcmp(&bl->md5[i * 16], bc->md5, 16) == 0) { return NGX_AGAIN; } cacheable++; } else if (free == -1) { free = i; } #if 1 if (cacheable == bl->cacheable) { if (free == -1 && cacheable < bl->max_busy) { free = i + 1; } break; } #endif mask >>= 1; b++; } if (free == -1) { return NGX_ERROR; } if (lock) { if (bl->busy == bl->max_busy) { return NGX_ERROR; } ngx_memcpy(&bl->md5[free * 16], bc->md5, 16); bl->md5_mask[free / 8] |= 1 << (free & 7); bc->slot = free; bl->cacheable++; bl->busy++; } return NGX_OK; } char *ngx_http_set_busy_lock_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { char *p = conf; ngx_uint_t i, dup, invalid; ngx_str_t *value, line; ngx_http_busy_lock_t *bl, **blp; blp = (ngx_http_busy_lock_t **) (p + cmd->offset); if (*blp) { return "is duplicate"; } /* ngx_calloc_shared() */ bl = ngx_pcalloc(cf->pool, sizeof(ngx_http_busy_lock_t)); if (bl == NULL) { return NGX_CONF_ERROR; } *blp = bl; /* ngx_calloc_shared() */ bl->mutex = ngx_pcalloc(cf->pool, sizeof(ngx_event_mutex_t)); if (bl->mutex == NULL) { return NGX_CONF_ERROR; } dup = 0; invalid = 0; value = cf->args->elts; for (i = 1; i < cf->args->nelts; i++) { if (value[i].data[1] != '=') { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid value \"%s\"", value[i].data); return NGX_CONF_ERROR; } switch (value[i].data[0]) { case 'b': if (bl->max_busy) { dup = 1; break; } bl->max_busy = ngx_atoi(value[i].data + 2, value[i].len - 2); if (bl->max_busy == NGX_ERROR) { invalid = 1; break; } continue; case 'w': if (bl->max_waiting) { dup = 1; break; } bl->max_waiting = ngx_atoi(value[i].data + 2, value[i].len - 2); if (bl->max_waiting == NGX_ERROR) { invalid = 1; break; } continue; case 't': if (bl->timeout) { dup = 1; break; } line.len = value[i].len - 2; line.data = value[i].data + 2; bl->timeout = ngx_parse_time(&line, 1); if (bl->timeout == (time_t) NGX_ERROR) { invalid = 1; break; } continue; default: invalid = 1; } if (dup) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "duplicate value \"%s\"", value[i].data); return NGX_CONF_ERROR; } if (invalid) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid value \"%s\"", value[i].data); return NGX_CONF_ERROR; } } if (bl->timeout == 0 && bl->max_waiting) { ngx_conf_log_error(NGX_LOG_WARN, cf, 0, "busy lock waiting is useless with zero timeout, ignoring"); } return NGX_CONF_OK; }