ash: expand: Fix skipping of command substitution when trimming in evalvar

Upstream commit:

    Date: Mon, 28 May 2018 17:09:48 +0800
    expand: Fix skipping of command substitution when trimming in evalvar

    When we are trimming an unset variable in evalvar, any embedded
    command substitution that should have been skipped are not.  This
    can cause them to be evaluated later should there be other command
    substitutions in the same input word.

    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 3958db123..97c7f4ef5 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -7506,6 +7506,8 @@ evalvar(char *p, int flag)
 		goto record;
 	}
 
+	varlen = 0;
+
  end:
 	if (subtype != VSNORMAL) {      /* skip to end of alternative */
 		int nesting = 1;