From: Alan <gnomes@lxorguk.ukuu.org.uk>
Date: Fri, 19 Feb 2016 12:56:57 +0000 (+0100)
Subject: lightnvm: fix up nonsensical configure overrun checking
X-Git-Tag: v4.6-rc1~96^2~18
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5e422cffe822874cefc1657cd287c8647b2782dd;p=platform%2Fkernel%2Flinux-exynos.git

lightnvm: fix up nonsensical configure overrun checking

Instead of checking a constant 0 actually check the space available. Even
better remember to allow for the header and also check the right amount of
space is needed.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 33224cb..782ac5d 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -870,20 +870,19 @@ static int nvm_configure_by_str_event(const char *val,
 
 static int nvm_configure_get(char *buf, const struct kernel_param *kp)
 {
-	int sz = 0;
-	char *buf_start = buf;
+	int sz;
 	struct nvm_dev *dev;
 
-	buf += sprintf(buf, "available devices:\n");
+	sz = sprintf(buf, "available devices:\n");
 	down_write(&nvm_lock);
 	list_for_each_entry(dev, &nvm_devices, devices) {
-		if (sz > 4095 - DISK_NAME_LEN)
+		if (sz > 4095 - DISK_NAME_LEN - 2)
 			break;
-		buf += sprintf(buf, " %32s\n", dev->name);
+		sz += sprintf(buf + sz, " %32s\n", dev->name);
 	}
 	up_write(&nvm_lock);
 
-	return buf - buf_start - 1;
+	return sz;
 }
 
 static const struct kernel_param_ops nvm_configure_by_str_event_param_ops = {