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Groups > linux.kernel > #1442299 > unrolled thread

[patch] dsp56k: prevent a harmless underflow

Started byDan Carpenter <dan.carpenter@oracle.com>
First post2016-07-13 12:20 +0200
Last post2016-07-13 17:10 +0200
Articles 2 — 2 participants

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  [patch] dsp56k: prevent a harmless underflow Dan Carpenter <dan.carpenter@oracle.com> - 2016-07-13 12:20 +0200
    Re: [patch] dsp56k: prevent a harmless underflow Arnd Bergmann <arnd@arndb.de> - 2016-07-13 17:10 +0200

#1442299 — [patch] dsp56k: prevent a harmless underflow

FromDan Carpenter <dan.carpenter@oracle.com>
Date2016-07-13 12:20 +0200
Subject[patch] dsp56k: prevent a harmless underflow
Message-ID<rUpqO-1JD-19@gated-at.bofh.it>
There is a mistake here where we don't allow "len" to be zero but we
allow negative lengths.  It's basically harmless in this case, but the
underflow makes my static checker complain.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/char/dsp56k.c b/drivers/char/dsp56k.c
index 8bf70e8..50aa9ba 100644
--- a/drivers/char/dsp56k.c
+++ b/drivers/char/dsp56k.c
@@ -325,7 +325,7 @@ static long dsp56k_ioctl(struct file *file, unsigned int cmd,
 			if(get_user(bin, &binary->bin) < 0)
 				return -EFAULT;
 		
-			if (len == 0) {
+			if (len <= 0) {
 				return -EINVAL;      /* nothing to upload?!? */
 			}
 			if (len > DSP56K_MAX_BINARY_LENGTH) {

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#1442535

FromArnd Bergmann <arnd@arndb.de>
Date2016-07-13 17:10 +0200
Message-ID<rUtXs-4Ju-29@gated-at.bofh.it>
In reply to#1442299
On Wednesday, July 13, 2016 1:11:19 PM CEST Dan Carpenter wrote:
> There is a mistake here where we don't allow "len" to be zero but we
> allow negative lengths.  It's basically harmless in this case, but the
> underflow makes my static checker complain.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

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