linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Roel Kluin <roel.kluin@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: lkml <linux-kernel@vger.kernel.org>
Subject: [PATCH] hvc_console: prevent wrapping in hvc_console_print()
Date: Tue, 17 Mar 2009 13:19:55 +0100	[thread overview]
Message-ID: <49BF956B.9030109@gmail.com> (raw)

This was found by code analysis, is it needed?
------------------------------>8-------------8<---------------------------------
If we subtract too much on unsigned i it wraps.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index 94e7e3c..d06313c 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -161,10 +161,10 @@ static void hvc_console_print(struct console *co, const char *b,
 			}
 		} else {
 			r = cons_ops[index]->put_chars(vtermnos[index], c, i);
-			if (r <= 0) {
+			if (r <= 0 || r > i) {
 				/* throw away chars on error */
 				i = 0;
-			} else if (r > 0) {
+			} else {
 				i -= r;
 				if (i > 0)
 					memmove(c, c+r, i);

             reply	other threads:[~2009-03-17 12:20 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-17 12:19 Roel Kluin [this message]
2009-03-30 20:35 ` [PATCH] hvc_console: prevent wrapping in hvc_console_print() Andrew Morton
2009-03-30 20:55   ` Josh Boyer
2009-03-30 21:18     ` Andrew Morton
2009-03-31 13:29       ` [PATCH] Add hvc_console to MAINTAINERS Josh Boyer
2009-03-31 21:10         ` Joe Perches
2009-03-31 21:22           ` Andrew Morton
2009-03-31 21:40             ` Joe Perches
2009-03-31 23:52               ` Josh Boyer
2009-03-31 23:44         ` Michael Ellerman
2009-03-31 23:50           ` Josh Boyer
2009-04-01  0:04             ` Michael Ellerman
2009-04-01  0:20               ` Michael Ellerman
2009-04-01  0:33                 ` Josh Boyer

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=49BF956B.9030109@gmail.com \
    --to=roel.kluin@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).