From: Ville Viinikka <ville@tuxera.com>
Date: Fri, 8 Jul 2016 15:27:02 +0000 (+0300)
Subject: mmc: block: fix free of uninitialized 'idata->buf'
X-Git-Tag: v4.6.6~28
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5e8087b375595abe0f9dc53bdc902d5b08c54d8b;p=thirdparty%2Fkernel%2Fstable.git

mmc: block: fix free of uninitialized 'idata->buf'

commit bfe5b1b1e013f7b1c0fd2ac3b3c8c380114b3fb9 upstream.

Set 'idata->buf' to NULL so that it never gets returned without
initialization. This fixes a bug where mmc_blk_ioctl_cmd() would
free both 'idata' and 'idata->buf' but 'idata->buf' was returned
uninitialized.

Fixes: 1ff8950c0433 ("mmc: block: change to use kmalloc when copy data from userspace")
Signed-off-by: Ville Viinikka <ville@tuxera.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index b0a27413cb134..39f5a75403b8d 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -352,8 +352,10 @@ static struct mmc_blk_ioc_data *mmc_blk_ioctl_copy_from_user(
 		goto idata_err;
 	}
 
-	if (!idata->buf_bytes)
+	if (!idata->buf_bytes) {
+		idata->buf = NULL;
 		return idata;
+	}
 
 	idata->buf = kmalloc(idata->buf_bytes, GFP_KERNEL);
 	if (!idata->buf) {