From: Harald van Dijk <harald@gigawatt.nl>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: calestyo@scientia.org, dash@vger.kernel.org
Subject: Re: [PATCH] expand: Always quote caret when using fnmatch
Date: Tue, 18 Jan 2022 08:44:05 +0000 [thread overview]
Message-ID: <c31fb498-0f82-dcdc-b1c6-212b8c919c07@gigawatt.nl> (raw)
In-Reply-To: <YeZadfOkUDdN7JqS@gondor.apana.org.au>
On 18/01/2022 06:13, Herbert Xu wrote:
> This patch forces ^ to be a literal when we use fnmatch.
>
> Fixes: 7638476c18f2 ("shell: Enable fnmatch/glob by default")
> Reported-by: Christoph Anton Mitterer <calestyo@scientia.org>
> Suggested-by: Harald van Dijk <harald@gigawatt.nl>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
>
> diff --git a/src/expand.c b/src/expand.c
> index aea5cc4..04bf8fb 100644
> --- a/src/expand.c
> +++ b/src/expand.c
> @@ -47,6 +47,9 @@
> #include <string.h>
> #ifdef HAVE_FNMATCH
> #include <fnmatch.h>
> +#define FNMATCH_IS_ENABLED 1
> +#else
> +#define FNMATCH_IS_ENABLED 0
> #endif
> #ifdef HAVE_GLOB
> #include <glob.h>
> @@ -1693,8 +1696,11 @@ _rmescapes(char *str, int flag)
> notescaped = 0;
> goto copy;
> }
> + if (FNMATCH_IS_ENABLED && *p == '^')
> + goto add_escape;
> if (*p == (char)CTLESC) {
> p++;
> +add_escape:
> if (notescaped)
> *q++ = '\\';
> }
>
The loop that is modified by this patch is only taken after any qchars
are seen, so for e.g.
var=abc
echo ${var#[^a]}
it has no effect. More importantly though, _rmescapes is used to modify
strings in place. This patch causes _rmescapes to try and grow strings,
which cannot ever work. A test case for this is
case aa in \a[^a]) echo match ;; esac
which fails with a segfault after this patch is applied.
Cheers,
Harald van Dijk
next prev parent reply other threads:[~2022-01-18 8:44 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-12 16:25 possible wrong behaviour with patterns using a quoted ^ at the start of a bracket expression Christoph Anton Mitterer
2022-01-12 17:20 ` Harald van Dijk
2022-01-12 17:47 ` Christoph Anton Mitterer
2022-01-12 18:17 ` Harald van Dijk
2022-01-12 18:21 ` Christoph Anton Mitterer
2022-01-18 6:13 ` [PATCH] expand: Always quote caret when using fnmatch Herbert Xu
2022-01-18 8:44 ` Harald van Dijk [this message]
2022-01-19 5:37 ` [v2 PATCH] " Herbert Xu
2022-02-20 7:15 ` Stephane Chazelas
2022-02-21 16:39 ` Eric Blake
2022-02-21 17:06 ` Harald van Dijk
2022-02-21 19:15 ` Stephane Chazelas
2022-01-18 14:29 ` [PATCH] " Christoph Anton Mitterer
2022-01-18 14:54 ` Chet Ramey
2022-01-18 22:33 ` Herbert Xu
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