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Message-ID: <20170609000030.GM1627@brightrain.aerifal.cx>
Date: Thu, 8 Jun 2017 20:00:30 -0400
From: Rich Felker <dalias@...c.org>
To: musl@...ts.openwall.com
Subject: Re: [PATCH] fix errno not being set to ERANGE by getgr,
getpw, and getspnam
On Tue, Jun 06, 2017 at 12:21:39PM -0400, Rudolph Pereira wrote:
> Hi,
>
> currently, the getgr, getpw, and getspnam functions in musl return ERANGE
> when the allocated buffer is not large enough, but do not set errno to the
> same value. This causes issues with utilities, for example the "shadow"
> utilities (useradd/mod, groupmod, etc.) which assume this behaviour (which
> at least gnu libc exhibits) and leads to groups having a small limit on the
> number of members.
>
> The attached patch, against 1.1.16, corrects this.
>
> Cheers,
> Rudolph
> --- musl-1.1.16.orig/src/passwd/getgr_r.c
> +++ musl-1.1.16/src/passwd/getgr_r.c
> @@ -1,5 +1,6 @@
> #include "pwf.h"
> #include <pthread.h>
> +#include <errno.h>
>
> #define FIX(x) (gr->gr_##x = gr->gr_##x-line+buf)
>
> @@ -19,6 +20,7 @@
> if (*res && size < len + (nmem+1)*sizeof(char *) + 32) {
> *res = 0;
> rv = ERANGE;
> + errno = ERANGE;
> }
> if (*res) {
> buf += (16-(uintptr_t)buf)%16;
> --- musl-1.1.16.orig/src/passwd/getpw_r.c
> +++ musl-1.1.16/src/passwd/getpw_r.c
> @@ -1,5 +1,6 @@
> #include "pwf.h"
> #include <pthread.h>
> +#include <errno.h>
>
> #define FIX(x) (pw->pw_##x = pw->pw_##x-line+buf)
>
> @@ -16,6 +17,7 @@
> if (*res && size < len) {
> *res = 0;
> rv = ERANGE;
> + errno = ERANGE;
> }
> if (*res) {
> memcpy(buf, line, len);
> --- musl-1.1.16.orig/src/passwd/getspnam_r.c
> +++ musl-1.1.16/src/passwd/getspnam_r.c
> @@ -3,6 +3,7 @@
> #include <sys/stat.h>
> #include <ctype.h>
> #include <pthread.h>
> +#include <errno.h>
> #include "pwf.h"
>
> /* This implementation support Openwall-style TCB passwords in place of
> @@ -104,6 +105,7 @@
> }
> if (buf[k-1] != '\n') {
> rv = ERANGE;
> + errno = ERANGE;
> break;
> }
I don't think this patch is complete. A nonzero value of rv can also
come from __getpw_a/__getgr_a. Insted, just before return there should
probably be:
if (rv) errno = rv;
Does that look correct? I'm not sure about getspnam_r; it might
actually be missing some error cases right now.
Rich
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