linux-kernel - bug reading /proc/sys/kernel/*: only first byte read.

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-next>] [day] [month] [year] [list]

Date:	Fri, 20 Oct 2006 16:43:39 +0400
From:	Michael Tokarev <mjt@....msk.ru>
To:	Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: bug reading /proc/sys/kernel/*: only first byte read.

I were debugging a weird problem with busybox, and come across
this chunk of strace output:

open("/proc/sys/kernel/osrelease", O_RDONLY) = 3
read(3, "2", 1)                         = 1
read(3, "", 1)                          = 0
close(3)                                = 0

As you can see, after reading one byte from /proc/sys/kernel/osrelease,
next read() returns 0, which is treated as end-of-file by an application.

Why busybox does this single-byte reads is another question (many
shells does that, in order to be able to stop reading at newline).

But this is definitely a bug in kernel, and should be fixed....

It exists in 2.6.17 and 2.6.18

Thanks.

/mjt
-
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/