Mercurial > hg > nginx-quic
view src/os/win32/ngx_event_log.c @ 7054:e02555553d0b
Range filter: protect from total size overflows.
The overflow can be used to circumvent the restriction on total size of
ranges introduced in c2a91088b0c0 (1.1.2). Additionally, overflow
allows producing ranges with negative start (such ranges can be created
by using a suffix, "bytes=-100"; normally this results in 200 due to
the total size check). These can result in the following errors in logs:
[crit] ... pread() ... failed (22: Invalid argument)
[alert] ... sendfile() failed (22: Invalid argument)
When using cache, it can be also used to reveal cache file header.
It is believed that there are no other negative effects, at least with
standard nginx modules.
In theory, this can also result in memory disclosure and/or segmentation
faults if multiple ranges are allowed, and the response is returned in a
single in-memory buffer. This never happens with standard nginx modules
though, as well as known 3rd party modules.
Fix is to properly protect from possible overflow when incrementing size.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 11 Jul 2017 16:06:23 +0300 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #define NGX_MAX_ERROR_STR 2048 void ngx_cdecl ngx_event_log(ngx_err_t err, const char *fmt, ...) { u_char *p, *last; long types; HKEY key; HANDLE ev; va_list args; u_char text[NGX_MAX_ERROR_STR]; const char *msgarg[9]; static u_char netmsg[] = "%SystemRoot%\\System32\\netmsg.dll"; last = text + NGX_MAX_ERROR_STR; p = text + GetModuleFileName(NULL, (char *) text, NGX_MAX_ERROR_STR - 50); *p++ = ':'; ngx_linefeed(p); va_start(args, fmt); p = ngx_vslprintf(p, last, fmt, args); va_end(args); if (err) { p = ngx_log_errno(p, last, err); } if (p > last - NGX_LINEFEED_SIZE - 1) { p = last - NGX_LINEFEED_SIZE - 1; } ngx_linefeed(p); *p = '\0'; /* * we do not log errors here since we use * Event Log only to log our own logs open errors */ if (RegCreateKeyEx(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Services\\EventLog\\Application\\nginx", 0, NULL, REG_OPTION_NON_VOLATILE, KEY_SET_VALUE, NULL, &key, NULL) != 0) { return; } if (RegSetValueEx(key, "EventMessageFile", 0, REG_EXPAND_SZ, netmsg, sizeof(netmsg) - 1) != 0) { return; } types = EVENTLOG_ERROR_TYPE; if (RegSetValueEx(key, "TypesSupported", 0, REG_DWORD, (u_char *) &types, sizeof(long)) != 0) { return; } RegCloseKey(key); ev = RegisterEventSource(NULL, "nginx"); msgarg[0] = (char *) text; msgarg[1] = NULL; msgarg[2] = NULL; msgarg[3] = NULL; msgarg[4] = NULL; msgarg[5] = NULL; msgarg[6] = NULL; msgarg[7] = NULL; msgarg[8] = NULL; /* * the 3299 event id in netmsg.dll has the generic message format: * "%1 %2 %3 %4 %5 %6 %7 %8 %9" */ ReportEvent(ev, EVENTLOG_ERROR_TYPE, 0, 3299, NULL, 9, 0, msgarg, NULL); DeregisterEventSource(ev); }