view auto/module @ 9300:5be23505292b

SSI: fixed incorrect or duplicate stub output. Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set if there are data in the first buffer sent in the subrequest. As a result, following the change mentioned this flag cannot be used to prevent duplicate ngx_http_ssi_stub_output() calls, since it is not set if there was already some output, but the first buffer was empty. Still, when there are multiple subrequests, even an empty subrequest response might be delayed by the postpone filter, leading to a second call of ngx_http_ssi_stub_output() during finalization from ngx_http_writer() the subreqest buffers are released by the postpone filter. Since r->request_output is not set after the first call, this resulted in duplicate stub output. Additionally, checking only the first buffer might be wrong in some unusual cases. For example, the first buffer might be empty if $r->flush() is called before printing any data in the embedded Perl module. Depending on the postpone_output value and corresponding sizes, this issue can result in either duplicate or unexpected stub output, or "zero size buf in writer" alerts. Following 8124:f5515e727656 (1.23.4), it became slightly easier to reproduce the issue, as empty static files and empty cache items now result in a response with an empty buffer. Before the change, an empty proxied response can be used to reproduce the issue. Fix is check all buffers and set r->request_output if any non-empty buffers are sent. This ensures that all unusual cases of non-empty responses are covered, and also that r->request_output will be set after the first stub output, preventing duplicate output. Reported by Jan Gassen.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 04 Jul 2024 17:41:28 +0300
parents 4b1299b1856a
children
line wrap: on
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# Copyright (C) Ruslan Ermilov
# Copyright (C) Nginx, Inc.


case $ngx_module_type in
    HTTP_*) ngx_var=HTTP ;;
    *)      ngx_var=$ngx_module_type ;;
esac


if [ "$ngx_module_link" = DYNAMIC ]; then

    for ngx_module in $ngx_module_name; do
        # extract the first name
        break
    done

    DYNAMIC_MODULES="$DYNAMIC_MODULES $ngx_module"

    eval ${ngx_module}_MODULES=\"$ngx_module_name\"

    if [ -z "$ngx_module_order" -a \
         \( "$ngx_module_type" = "HTTP_FILTER" \
         -o "$ngx_module_type" = "HTTP_AUX_FILTER" \) ]
    then
        eval ${ngx_module}_ORDER=\"$ngx_module_name \
                                   ngx_http_copy_filter_module\"
    else
        eval ${ngx_module}_ORDER=\"$ngx_module_order\"
    fi

    srcs=
    shrd=
    for src in $ngx_module_srcs
    do
        found=no
        for old in $DYNAMIC_MODULES_SRCS
        do
            if [ $src = $old ]; then
                found=yes
                break
            fi
        done

        if [ $found = no ]; then
            srcs="$srcs $src"
        else
            shrd="$shrd $src"
        fi
    done
    eval ${ngx_module}_SRCS=\"$srcs\"
    eval ${ngx_module}_SHRD=\"$shrd\"

    DYNAMIC_MODULES_SRCS="$DYNAMIC_MODULES_SRCS $srcs"

    if test -n "$ngx_module_incs"; then
        CORE_INCS="$CORE_INCS $ngx_module_incs"
    fi

    if test -n "$ngx_module_deps"; then
        NGX_ADDON_DEPS="$NGX_ADDON_DEPS $ngx_module_deps"
    fi

    libs=
    for lib in $ngx_module_libs
    do
        case $lib in

            LIBXSLT | LIBGD | GEOIP | PERL)
                libs="$libs \$NGX_LIB_$lib"

                if eval [ "\$USE_${lib}" = NO ] ; then
                    eval USE_${lib}=DYNAMIC
                fi
            ;;

            PCRE | OPENSSL | ZLIB)
                eval USE_${lib}=YES
            ;;

            MD5 | SHA1)
                # obsolete
            ;;

            *)
                libs="$libs $lib"
            ;;

        esac
    done
    eval ${ngx_module}_LIBS=\'$libs\'

elif [ "$ngx_module_link" = YES ]; then

    eval ${ngx_module_type}_MODULES=\"\$${ngx_module_type}_MODULES \
                                      $ngx_module_name\"

    eval ${ngx_var}_SRCS=\"\$${ngx_var}_SRCS $ngx_module_srcs\"

    if test -n "$ngx_module_incs"; then
        eval ${ngx_var}_INCS=\"\$${ngx_var}_INCS $ngx_module_incs\"
    fi

    if test -n "$ngx_module_deps"; then
        eval ${ngx_var}_DEPS=\"\$${ngx_var}_DEPS $ngx_module_deps\"
    fi

    for lib in $ngx_module_libs
    do
        case $lib in

            PCRE | OPENSSL | ZLIB | LIBXSLT | LIBGD | PERL | GEOIP)
                eval USE_${lib}=YES
            ;;

            MD5 | SHA1)
                # obsolete
            ;;

            *)
                CORE_LIBS="$CORE_LIBS $lib"
            ;;

        esac
    done

elif [ "$ngx_module_link" = ADDON ]; then

    eval ${ngx_module_type}_MODULES=\"\$${ngx_module_type}_MODULES \
                                      $ngx_module_name\"

    srcs=
    for src in $ngx_module_srcs
    do
        found=no
        for old in $NGX_ADDON_SRCS
        do
            if [ $src = $old ]; then
                found=yes
                break
            fi
        done

        if [ $found = no ]; then
            srcs="$srcs $src"
        fi
    done

    NGX_ADDON_SRCS="$NGX_ADDON_SRCS $srcs"

    if test -n "$ngx_module_incs"; then
        eval ${ngx_var}_INCS=\"\$${ngx_var}_INCS $ngx_module_incs\"
    fi

    if test -n "$ngx_module_deps"; then
        NGX_ADDON_DEPS="$NGX_ADDON_DEPS $ngx_module_deps"
    fi

    for lib in $ngx_module_libs
    do
        case $lib in

            PCRE | OPENSSL | ZLIB | LIBXSLT | LIBGD | PERL | GEOIP)
                eval USE_${lib}=YES
            ;;

            MD5 | SHA1)
                # obsolete
            ;;

            *)
                CORE_LIBS="$CORE_LIBS $lib"
            ;;

        esac
    done
fi