From: Rich Felker <dalias@aerifal.cx>
To: musl@lists.openwall.com
Subject: Re: wcsncpy bug
Date: Sun, 22 May 2011 21:51:37 -0400 [thread overview]
Message-ID: <20110523015137.GT277@brightrain.aerifal.cx> (raw)
In-Reply-To: <20110523012547.GH6142@port70.net>
On Mon, May 23, 2011 at 03:25:47AM +0200, Szabolcs Nagy wrote:
> wcsncpy(d,s,n) did not decrease n while copying the '\0'
> so when s[0]=0 and n=1 it wrote 2 zeros to d
> diff --git a/src/string/wcsncpy.c b/src/string/wcsncpy.c
> index 0164208..fbd0631 100644
> --- a/src/string/wcsncpy.c
> +++ b/src/string/wcsncpy.c
> @@ -3,7 +3,7 @@
> wchar_t *wcsncpy(wchar_t *d, const wchar_t *s, size_t n)
> {
> wchar_t *a = d;
> - while (n && (*d++ = *s++)) n--;
> + while (n-- && (*d++ = *s++));
> wmemset(d, 0, n);
Yes it was broken but this patch is too. It will now clobber all
memory if the source string does not contain a null terminator, since
the final value of n after the while loop will be (size_t)-1.
Thanks for catching this bug tho. I'll fix it.
Rich
next prev parent reply other threads:[~2011-05-23 1:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-23 1:25 Szabolcs Nagy
2011-05-23 1:51 ` Rich Felker [this message]
2011-05-23 2:00 ` Rich Felker
2011-05-23 2:16 ` Szabolcs Nagy
2011-05-23 2:10 ` Szabolcs Nagy
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