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

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>]

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)),
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
To unsubscribe from this list: send the line "unsubscribe dash" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html