view auto/module @ 8460:3974f4e56a4e

Mail: fixed s->arg_start clearing on invalid IMAP commands. Previously, s->arg_start was left intact after invalid IMAP commands, and this might result in an argument incorrectly added to the following command. Similarly, s->backslash was left intact as well, leading to unneeded backslash removal. For example (LFs from the client are explicitly shown as "<LF>"): S: * OK IMAP4 ready C: a01 login "\<LF> S: a01 BAD invalid command C: a0000000000\2 authenticate <LF> S: a00000000002 aBAD invalid command The backslash followed by LF generates invalid command with s->arg_start and s->backslash set, the following command incorrectly treats anything from the old s->arg_start to the space after the command as an argument, and removes the backslash from the tag. If there is no space, s->arg_end will be NULL. Both things seem to be harmless though. In particular: - This can be used to provide an incorrect argument to a command without arguments. The only command which seems to look at the single argument is AUTHENTICATE, and it checks the argument length before trying to access it. - Backslash removal uses the "end" pointer, and stops due to "src < end" condition instead of scanning all the process memory if s->arg_end is NULL (and arg[0].len is huge). - There should be no backslashes in unquoted strings. An obvious fix is to clear s->arg_start and s->backslash on invalid commands, similarly to how it is done in POP3 parsing (added in 810:e3aa8f305d21) and SMTP parsing. This, however, makes it clear that s->arg_start handling in the "done" label is wrong: s->arg_start cannot be legitimately set there, as it is expected to be cleared in all possible cases when the "done" label is reached. The relevant code is dead and will be removed by the following change.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 19 May 2021 03:13:20 +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