klibc - Mar 2020 - [klibc:update-dash] dash: [PARSER] Catch variable length expansions on non-existant specials

Commit-ID:  da8fe1346c93b339333207adecd8493ca1cb403a
Gitweb:    
http://git.kernel.org/?p=libs/klibc/klibc.git;a=commit;h=da8fe1346c93b339333207adecd8493ca1cb403a
Author:     Herbert Xu <herbert at gondor.apana.org.au>
AuthorDate: Thu, 30 Oct 2014 11:53:35 +0800
Committer:  Ben Hutchings <ben at decadent.org.uk>
CommitDate: Sat, 28 Mar 2020 21:42:54 +0000

[klibc] dash: [PARSER] Catch variable length expansions on non-existant specials

[ dash commit cbd6165076cbbf18e68a292f80c1d454fdbedc22 ]

Currently we only check special variable names that follow directly
after $ or ${.  So errors such as ${#&} are not caught.  This patch
fixes that by moving the is_special check to just before we print out
the special variable name.

Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
Signed-off-by: Ben Hutchings <ben at decadent.org.uk>

---
 usr/dash/parser.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/usr/dash/parser.c b/usr/dash/parser.c
index 382ddf24..382658e7 100644
--- a/usr/dash/parser.c
+++ b/usr/dash/parser.c
@@ -1229,8 +1229,7 @@ varname:
 				STPUTC(c, out);
 				c = pgetc_eatbnl();
 			} while (is_digit(c));
-		}
-		else if (is_special(c)) {
+		} else {
 			int cc = c;
 
 			c = pgetc_eatbnl();
@@ -1251,10 +1250,14 @@ varname:
 				}
 			}
 
+			if (!is_special(cc)) {
+				if (subtype == VSLENGTH)
+					subtype = 0;
+				goto badsub;
+			}
+
 			USTPUTC(cc, out);
 		}
-		else
-			goto badsub;
 
 		if (subtype == 0) {
 			switch (c) {