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Message-Id: <20070624145837.f3141572.akpm@linux-foundation.org>
Date: Sun, 24 Jun 2007 14:58:37 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Jesper Juhl <jesper.juhl@...il.com>
Cc: Richard Henderson <rth@...u.edu>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Avoid potential NULL deref in scripts/genksyms/lex.l
On Sun, 24 Jun 2007 23:40:03 +0200 Jesper Juhl <jesper.juhl@...il.com> wrote:
> strchr() returns NULL in case the string is not found and if that
> happens we risk dereferencing a NULL pointer. It never hurts to
> check for that condition and exit normally with an error rather
> than crashing.
>
> (no, the indentation is not according to CodingStyle, it's simply
> following whatever else is in that file)
>
>
> Signed-off-by: Jesper Juhl <jesper.juhl@...il.com>
> ---
>
> scripts/genksyms/lex.l | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/scripts/genksyms/lex.l b/scripts/genksyms/lex.l
> index 5e544a0..28edc0c 100644
> --- a/scripts/genksyms/lex.l
> +++ b/scripts/genksyms/lex.l
> @@ -154,6 +154,8 @@ repeat:
>
> file = strchr(yytext, '\"')+1;
> e = strchr(file, '\"');
If `file' can be null we'd have oopsed here.
> + if (!file || !e)
> + exit(1);
> *e = '\0';
> cur_filename = memcpy(xmalloc(e-file+1), file, e-file+1);
> cur_line = atoi(yytext+2);
I don't think the bug which you're fixing can occur:
^#[ \t]+{INT}[ \t]+\"[^\"\n]+\".*\n return FILENAME;
has anyone reported crashes in there?
-
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