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view auto/os/conf @ 6359:dac6eda40475 stable-1.8

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Resolver: fixed use-after-free memory accesses with CNAME. When several requests were waiting for a response, then after getting a CNAME response only the last request's context had the name updated. Contexts of other requests had the wrong name. This name was used by ngx_resolve_name_done() to find the node to remove the request context from. When the name was wrong, the request could not be properly cancelled, its context was freed but stayed linked to the node's waiting list. This happened e.g. when the first request was aborted or timed out before the resolving completed. When it completed, this triggered a use-after-free memory access by calling ctx->handler of already freed request context. The bug manifests itself by "could not cancel <name> resolving" alerts in error_log. When a request was responded with a CNAME, the request context kept the pointer to the original node's rn->u.cname. If the original node expired before the resolving timed out or completed with an error, this would trigger a use-after-free memory access via ctx->name in ctx->handler(). The fix is to keep ctx->name unmodified. The name from context is no longer used by ngx_resolve_name_done(). Instead, we now keep the pointer to resolver node to which this request is linked. Keeping the original name intact also improves logging.
author Roman Arutyunyan <arut@nginx.com>
date Tue, 26 Jan 2016 16:46:59 +0300
parents 489839d07b38
children a88e309f839b
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# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


echo "checking for $NGX_SYSTEM specific features"

case "$NGX_PLATFORM" in

    FreeBSD:*)
        . auto/os/freebsd
    ;;

    Linux:*)
        . auto/os/linux
    ;;

    SunOS:*)
        . auto/os/solaris
    ;;

    Darwin:*)
        . auto/os/darwin
    ;;

    win32)
        . auto/os/win32
    ;;

    DragonFly:*)
        have=NGX_FREEBSD . auto/have_headers
        CORE_INCS="$UNIX_INCS"
        CORE_DEPS="$UNIX_DEPS $FREEBSD_DEPS"
        CORE_SRCS="$UNIX_SRCS $FREEBSD_SRCS"

        echo " + sendfile() found"
        have=NGX_HAVE_SENDFILE . auto/have
        CORE_SRCS="$CORE_SRCS $FREEBSD_SENDFILE_SRCS"

        ngx_spacer='
'
    ;;

    HP-UX:*)
        # HP/UX
        have=NGX_HPUX . auto/have_headers
        CORE_INCS="$UNIX_INCS"
        CORE_DEPS="$UNIX_DEPS $POSIX_DEPS"
        CORE_SRCS="$UNIX_SRCS"
        CC_AUX_FLAGS="$CC_AUX_FLAGS -D_XOPEN_SOURCE -D_XOPEN_SOURCE_EXTENDED=1"
        CC_AUX_FLAGS="$CC_AUX_FLAGS -D_HPUX_ALT_XOPEN_SOCKET_API"
    ;;

    OSF1:*)
        # Tru64 UNIX
        have=NGX_TRU64 . auto/have_headers
        have=NGX_HAVE_STRERROR_R . auto/nohave
        CORE_INCS="$UNIX_INCS"
        CORE_DEPS="$UNIX_DEPS $POSIX_DEPS"
        CORE_SRCS="$UNIX_SRCS"
    ;;

    *)
        CORE_INCS="$UNIX_INCS"
        CORE_DEPS="$UNIX_DEPS $POSIX_DEPS"
        CORE_SRCS="$UNIX_SRCS"
    ;;

esac


case "$NGX_MACHINE" in

    i386 | i686 | i86pc)
        have=NGX_HAVE_NONALIGNED . auto/have
        NGX_MACH_CACHE_LINE=32
    ;;

    amd64 | x86_64)
        have=NGX_HAVE_NONALIGNED . auto/have
        NGX_MACH_CACHE_LINE=64
    ;;

    sun4u | sun4v | sparc | sparc64)
        have=NGX_ALIGNMENT value=16 . auto/define
        # TODO
        NGX_MACH_CACHE_LINE=64
    ;;

    ia64 )
        have=NGX_ALIGNMENT value=16 . auto/define
        # TODO
        NGX_MACH_CACHE_LINE=64
    ;;

    *)
        have=NGX_ALIGNMENT value=16 . auto/define
        NGX_MACH_CACHE_LINE=32
    ;;

esac

if test -z "$NGX_CPU_CACHE_LINE"; then
    NGX_CPU_CACHE_LINE=$NGX_MACH_CACHE_LINE
fi

have=NGX_CPU_CACHE_LINE value=$NGX_CPU_CACHE_LINE . auto/define