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view auto/types/sizeof @ 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 | e3faa5fb7772 |
children |
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# Copyright (C) Igor Sysoev # Copyright (C) Nginx, Inc. echo $ngx_n "checking for $ngx_type size ...$ngx_c" cat << END >> $NGX_AUTOCONF_ERR ---------------------------------------- checking for $ngx_type size END ngx_size= cat << END > $NGX_AUTOTEST.c #include <sys/types.h> #include <sys/time.h> $NGX_INCLUDE_UNISTD_H #include <signal.h> #include <stdio.h> #include <sys/resource.h> $NGX_INCLUDE_INTTYPES_H $NGX_INCLUDE_AUTO_CONFIG_H int main(void) { printf("%d", (int) sizeof($ngx_type)); return 0; } END ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \ -o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT $ngx_feature_libs" eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1" if [ -x $NGX_AUTOTEST ]; then ngx_size=`$NGX_AUTOTEST` echo " $ngx_size bytes" fi case $ngx_size in 4) ngx_max_value=2147483647 ngx_max_len='(sizeof("-2147483648") - 1)' ;; 8) ngx_max_value=9223372036854775807LL ngx_max_len='(sizeof("-9223372036854775808") - 1)' ;; *) echo echo "$0: error: can not detect $ngx_type size" echo "----------" >> $NGX_AUTOCONF_ERR cat $NGX_AUTOTEST.c >> $NGX_AUTOCONF_ERR echo "----------" >> $NGX_AUTOCONF_ERR echo $ngx_test >> $NGX_AUTOCONF_ERR echo "----------" >> $NGX_AUTOCONF_ERR rm -rf $NGX_AUTOTEST* exit 1 esac rm -rf $NGX_AUTOTEST*