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.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


if [ "$NGX_PLATFORM" != win32 ]; then

    ngx_feature="C compiler"
    ngx_feature_name=
    ngx_feature_run=yes
    ngx_feature_incs=
    ngx_feature_path=
    ngx_feature_libs=
    ngx_feature_test=
    . auto/feature

    if [ $ngx_found = no ]; then
        echo
        echo $0: error: C compiler $CC is not found
        echo
        exit 1
    fi

fi


if [ "$CC" = cl ]; then
    NGX_CC_NAME=msvc
    echo " + using Microsoft Visual C++ compiler"

elif [ "$CC" = wcl386 ]; then
    NGX_CC_NAME=owc
    echo " + using Open Watcom C compiler"

elif [ "$CC" = bcc32 ]; then
    NGX_CC_NAME=bcc
    echo " + using Borland C++ compiler"

elif `$CC -V 2>&1 | grep '^Intel(R) C' >/dev/null 2>&1`; then
    NGX_CC_NAME=icc
    echo " + using Intel C++ compiler"

elif `$CC -v 2>&1 | grep 'gcc version' >/dev/null 2>&1`; then
    NGX_CC_NAME=gcc
    echo " + using GNU C compiler"

elif `$CC -v 2>&1 | grep 'clang version' >/dev/null 2>&1`; then
    NGX_CC_NAME=clang
    echo " + using Clang C compiler"

elif `$CC -v 2>&1 | grep 'LLVM version' >/dev/null 2>&1`; then
    NGX_CC_NAME=clang
    echo " + using Clang C compiler"

elif `$CC -V 2>&1 | grep 'Sun C' >/dev/null 2>&1`; then
    NGX_CC_NAME=sunc
    echo " + using Sun C compiler"

elif `$CC -V 2>&1 | grep '^Compaq C' >/dev/null 2>&1`; then
    NGX_CC_NAME=ccc
    echo " + using Compaq C compiler"

elif `$CC -V 2>&1 | grep '^aCC: ' >/dev/null 2>&1`; then
    NGX_CC_NAME=acc
    echo " + using HP aC++ compiler"

else
    NGX_CC_NAME=unknown

fi