From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Julien Grall <julien@xen.org>, Wei Liu <wl@xen.org>,
Konrad Wilk <konrad.wilk@oracle.com>,
George Dunlap <George.Dunlap@eu.citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ilja Van Sprundel <ivansprundel@ioactive.com>,
Ian Jackson <ian.jackson@citrix.com>
Subject: [Xen-devel] [PATCH] console: avoid buffer overflow in guest_console_write()
Date: Fri, 29 Nov 2019 11:13:18 +0100 [thread overview]
Message-ID: <5766dd2b-2aa7-bafe-56ad-3ea33ddf4591@suse.com> (raw)
The switch of guest_console_write()'s second parameter from plain to
unsigned int has caused the function's main loop header to no longer
guard the min_t() use within the function against effectively negative
values, due to the casts hidden inside the macro. Replace by a plain
min(), converting one of the arguments suitably without involving any
cast.
Fixes: ea601ec9995b ("xen/console: Rework HYPERCALL_console_io interface")
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -538,7 +538,7 @@ static long guest_console_write(XEN_GUES
__HYPERVISOR_console_io, "iih",
CONSOLEIO_write, count, buffer);
- kcount = min_t(int, count, sizeof(kbuf)-1);
+ kcount = min(count + sizeof(char[0]), sizeof(kbuf) - 1);
if ( copy_from_guest(kbuf, buffer, kcount) )
return -EFAULT;
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next reply other threads:[~2019-11-29 10:13 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-29 10:13 Jan Beulich [this message]
2019-11-29 10:22 ` [Xen-devel] [PATCH] console: avoid buffer overflow in guest_console_write() Andrew Cooper
2019-11-29 10:27 ` Jan Beulich
2019-11-29 12:01 ` Ian Jackson
2019-11-29 12:04 ` Andrew Cooper
2019-11-29 12:13 ` Jan Beulich
2019-11-29 12:15 ` Andrew Cooper
2019-11-29 12:19 ` Jan Beulich
2019-11-29 12:37 ` Andrew Cooper
2019-11-29 13:26 ` Jan Beulich
2019-11-29 13:37 ` Jürgen Groß
2019-11-29 13:55 ` Jan Beulich
2019-11-29 13:57 ` Andrew Cooper
2019-11-29 13:57 ` Jürgen Groß
2019-11-29 10:39 ` Julien Grall
2019-11-29 11:59 ` Ian Jackson
2019-11-29 12:15 ` Jan Beulich
2019-11-29 12:17 ` Andrew Cooper
2019-11-29 12:02 ` Jürgen Groß
2019-11-29 14:35 ` [Xen-devel] [PATCH XTF] CONSOLEIO_write stack overflow PoC Andrew Cooper
2019-11-29 14:43 ` Jan Beulich
2019-11-29 14:45 ` Jan Beulich
2019-11-29 14:50 ` Andrew Cooper
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