Re: dash bug: double-quoted "\" breaks glob protection for next char

[Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx>]

On Mon, Apr 2, 2018 at 7:04 PM, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
> On Mon, Apr 02, 2018 at 02:13:03PM +0200, Denys Vlasenko wrote:
>>
>> I was trying some of the beautiful atrocities from one of earlier
>> Harald's emails and this one fails in current dash git:
>>
>> # x="''''"; echo "${x#"${x+''}"''}"
>> dash: 12: Syntax error: Missing '}'
>
> Thanks for the report.  This patch should fix it.
>
> ---8<---
> Subject: parser: Fix parameter expansion inside inner double quotes
>
> The parsing of parameter expansion inside inner double quotes
> breaks because we never look for ENDVAR while innerdq is true.
>
>         echo "${x#"${x+''}"''}
>
> This patch fixes it by pushing the syntax stack if innerdq is
> true and we enter a new parameter expansion.
>
> This patch also fixes a corner case where a bad substitution error
> occurs within arithmetic expansion.
>
> Reported-by: Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx>
> Fixes: ab1cecb40478 (" parser: Add syntax stack for recursive...")
> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
>
> diff --git a/src/parser.c b/src/parser.c
> index 6a8a4a4..a856458 100644
> --- a/src/parser.c
> +++ b/src/parser.c
> @@ -1324,10 +1324,11 @@ badsub:
>                         pungetc();
>                 }
>
> -               if (newsyn == ARISYNTAX && subtype > VSNORMAL)
> +               if (newsyn == ARISYNTAX)
>                         newsyn = DQSYNTAX;
>
> -               if (newsyn != synstack->syntax) {
> +               if ((newsyn != synstack->syntax || synstack->innerdq) &&
> +                   subtype != VSNORMAL) {
>                         synstack_push(&synstack,
>                                       synstack->prev ?:
>                                       alloca(sizeof(*synstack)),


Verified, thanks!
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