From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Kevin Tian <kevin.tian@intel.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Jan Beulich <JBeulich@suse.com>
Subject: [PATCH 3/3] x86/microcode: Avoid undefined behaviour from signed integer overflow
Date: Fri, 5 Aug 2016 14:50:13 +0100 [thread overview]
Message-ID: <1470405013-18856-3-git-send-email-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <1470405013-18856-1-git-send-email-andrew.cooper3@citrix.com>
The checksum should be calculated using unsigned 32bit integers, as it is
intended to overflow and end at 0.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Kevin Tian <kevin.tian@intel.com>
CC: Jun Nakajima <jun.nakajima@intel.com>
---
xen/arch/x86/microcode_intel.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/microcode_intel.c b/xen/arch/x86/microcode_intel.c
index 6949c25..5b411b4 100644
--- a/xen/arch/x86/microcode_intel.c
+++ b/xen/arch/x86/microcode_intel.c
@@ -143,7 +143,8 @@ static int microcode_sanity_check(void *mc)
struct extended_sigtable *ext_header = NULL;
struct extended_signature *ext_sig;
unsigned long total_size, data_size, ext_table_size;
- int sum, orig_sum, ext_sigcount = 0, i;
+ uint32_t sum, orig_sum;
+ int ext_sigcount = 0, i;
total_size = get_totalsize(mc_header);
data_size = get_datasize(mc_header);
@@ -201,7 +202,7 @@ static int microcode_sanity_check(void *mc)
orig_sum = 0;
i = (MC_HEADER_SIZE + data_size) / DWSIZE;
while ( i-- )
- orig_sum += ((int *)mc)[i];
+ orig_sum += ((uint32_t *)mc)[i];
if ( orig_sum )
{
printk(KERN_ERR "microcode: aborting, bad checksum\n");
--
2.1.4
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-08-05 13:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-05 13:50 [PATCH 1/3] xen/common: Avoid undefined behaviour by shifting into a sign bit Andrew Cooper
2016-08-05 13:50 ` [PATCH 2/3] xen/x86: " Andrew Cooper
2016-08-05 14:06 ` Jan Beulich
2016-08-05 13:50 ` Andrew Cooper [this message]
2016-08-05 14:09 ` [PATCH 3/3] x86/microcode: Avoid undefined behaviour from signed integer overflow Jan Beulich
2016-08-11 8:42 ` Tian, Kevin
2016-08-05 14:04 ` [PATCH 1/3] xen/common: Avoid undefined behaviour by shifting into a sign bit Jan Beulich
2016-08-05 14:07 ` George Dunlap
2016-08-09 12:48 ` [PATCH] " Andrew Cooper
2016-08-09 12:48 ` [PATCH] xen/x86: " Andrew Cooper
2016-08-09 12:48 ` [PATCH] x86/microcode: Avoid undefined behaviour from signed integer overflow Andrew Cooper
2016-08-09 14:00 ` [PATCH] xen/common: Avoid undefined behaviour by shifting into a sign bit Jan Beulich
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1470405013-18856-3-git-send-email-andrew.cooper3@citrix.com \
--to=andrew.cooper3@citrix.com \
--cc=JBeulich@suse.com \
--cc=jun.nakajima@intel.com \
--cc=kevin.tian@intel.com \
--cc=xen-devel@lists.xen.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.