lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Sat, 16 Feb 2008 21:29:01 -0600
From:	Paul Jackson <pj@....com>
To:	Paul Menage <menage@...gle.com>
Cc:	balbir@...ibm.com, xemul@...nvz.org,
	kamezawa.hiroyu@...fujitsu.com, vatsa@...ux.vnet.ibm.com,
	akpm@...ux-foundation.org, containers@...ts.linux-foundation.org,
	linux-kernel@...r.kernel.org
Subject: Re: [RFC][PATCH 7/7] CGroup API: Update cpusets to use cgroup
 structured file API

Ok ... this would (I suspect, just from code reading, no bytes were
harmed in actual testing of this) have a minor change to how white
space is handled writing integer flags to cpuset files, and a minor
inconstency.

 1) Existing cpuset code lets you set a flag (e.g. cpu_exclusive) by doing:
	echo '1 rumplestiltskin' > cpu_exclusive   # same as: echo 1 > cpu_exclusive
    With this patch, that probably fails, EINVAL.

 2) With this patch, one can write "1" or "1\n" to cpuset integer files, but one
    cannot successfully write "1\r\n" or "1 " or "1 \n".  However, for the cpuset
    control files that take strings, not single integers, one -can- have any mix
    of trailing white space.

So far as I know, I have no requirement to write rumplestiltskin to cpuset files ;).
So I'm content to let the minor change in (1) pass without further comment.

I'd like to recommend consideration of the following patch, to address the
minor inconsistency of (2), and to save a few bytes of kernel text space.

=======

From: Paul Jackson <pj@....com>

Strip all trailing whitespace (such as carriage returns)
when parsing integer writes to cgroup files, not just
one trailing newline if present.

Signed-off-by: Paul Jackson <pj@....com>
Cc: Paul Menage <menage@...gle.com>

---
 kernel/cgroup.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- 2.6.24-mm1.orig/kernel/cgroup.c	2008-02-16 04:20:33.000000000 -0800
+++ 2.6.24-mm1/kernel/cgroup.c	2008-02-16 19:00:41.207478218 -0800
@@ -1321,10 +1321,7 @@ static ssize_t cgroup_write_uint(struct 
 		return -EFAULT;
 
 	buffer[nbytes] = 0;     /* nul-terminate */
-
-	/* strip newline if necessary */
-	if (nbytes && (buffer[nbytes-1] == '\n'))
-		buffer[nbytes-1] = 0;
+	strstrip(buffer);	/* strip -just- trailing whitespace */
 	val = simple_strtoull(buffer, &end, 0);
 	if (*end)
 		return -EINVAL;


-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@....com> 1.940.382.4214
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists