From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: [PATCH] fix fgetwc when decoding a character that crosses buffer boundary
Date: Sat, 18 Nov 2017 20:12:57 -0500 [thread overview]
Message-ID: <20171119011257.GG1627@brightrain.aerifal.cx> (raw)
In-Reply-To: <20171118165148.GF15263@port70.net>
[-- Attachment #1: Type: text/plain, Size: 1010 bytes --]
On Sat, Nov 18, 2017 at 05:51:48PM +0100, Szabolcs Nagy wrote:
> Update the buffer position according to the bytes consumed into st when
> decoding an incomplete character at the end of the buffer.
> ---
> src/stdio/fgetwc.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/src/stdio/fgetwc.c b/src/stdio/fgetwc.c
> index e455cfec..a00c1a86 100644
> --- a/src/stdio/fgetwc.c
> +++ b/src/stdio/fgetwc.c
> @@ -15,20 +15,21 @@ static wint_t __fgetwc_unlocked_internal(FILE *f)
> if (f->rpos < f->rend) {
> l = mbrtowc(&wc, (void *)f->rpos, f->rend - f->rpos, &st);
> if (l+2 >= 2) {
> f->rpos += l + !l; /* l==0 means 1 byte, null */
> return wc;
> }
> if (l == -1) {
> f->rpos++;
> return WEOF;
> }
> + f->rpos = f->rend;
> } else l = -2;
Thanks, applying! Here is a test case that demonstrates the bug
reproducibly; feel free to adapt (it should probably use the framework
functions for getting a utf-8 locale and error reporting) & include it
in libc-test.
Rich
[-- Attachment #2: fgetwc2.c --]
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#include <stdio.h>
#include <poll.h>
#include <locale.h>
#include <wchar.h>
#include <unistd.h>
int main()
{
setlocale(LC_CTYPE, "");
int p[2];
pipe(p);
write(p[1], "x\340\240", 3);
dup2(p[0], 0);
wchar_t wc;
wc = fgetwc(stdin);
write(p[1], "\200", 1);
close(p[1]);
wc = fgetwc(stdin);
printf("got %x\n", wc);
}
next prev parent reply other threads:[~2017-11-19 1:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-18 16:51 Szabolcs Nagy
2017-11-19 1:12 ` Rich Felker [this message]
2017-11-19 1:14 ` Rich Felker
2017-11-20 1:48 ` Further wide stdio issues [Was: Re: [PATCH] fix fgetwc when decoding a character that crosses buffer boundary] Rich Felker
2017-11-20 19:28 ` Rich Felker
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