From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 5 Dec 2013 17:53:50 +0300 From: Dan Carpenter To: David Woodhouse Subject: [patch v2] mtd: sm_ftl: heap corruption in sm_create_sysfs_attributes() Message-ID: <20131205145349.GA13302@elgon.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52A06B00.7070309@bfs.de> Cc: kernel-janitors@vger.kernel.org, linux-mtd@lists.infradead.org, walter harms List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , We always put a NUL terminator one space past the end of the "vendor" buffer. Walter Harms also pointed out that this should just use kstrndup(). Fixes: 7d17c02a01a1 ('mtd: Add new SmartMedia/xD FTL') Signed-off-by: Dan Carpenter --- v2: Use kstrndup(). Don't subtract 1 from the strnlen() limiter for the NUL. I think it's ok to go over? diff --git a/drivers/mtd/sm_ftl.c b/drivers/mtd/sm_ftl.c index 4b8e89583f2a..cf49c22673b9 100644 --- a/drivers/mtd/sm_ftl.c +++ b/drivers/mtd/sm_ftl.c @@ -59,15 +59,12 @@ static struct attribute_group *sm_create_sysfs_attributes(struct sm_ftl *ftl) struct attribute_group *attr_group; struct attribute **attributes; struct sm_sysfs_attribute *vendor_attribute; + char *vendor; - int vendor_len = strnlen(ftl->cis_buffer + SM_CIS_VENDOR_OFFSET, - SM_SMALL_PAGE - SM_CIS_VENDOR_OFFSET); - - char *vendor = kmalloc(vendor_len, GFP_KERNEL); + vendor = kstrndup(ftl->cis_buffer + SM_CIS_VENDOR_OFFSET, + SM_SMALL_PAGE - SM_CIS_VENDOR_OFFSET, GFP_KERNEL); if (!vendor) goto error1; - memcpy(vendor, ftl->cis_buffer + SM_CIS_VENDOR_OFFSET, vendor_len); - vendor[vendor_len] = 0; /* Initialize sysfs attributes */ vendor_attribute = @@ -78,7 +75,7 @@ static struct attribute_group *sm_create_sysfs_attributes(struct sm_ftl *ftl) sysfs_attr_init(&vendor_attribute->dev_attr.attr); vendor_attribute->data = vendor; - vendor_attribute->len = vendor_len; + vendor_attribute->len = strlen(vendor); vendor_attribute->dev_attr.attr.name = "vendor"; vendor_attribute->dev_attr.attr.mode = S_IRUGO; vendor_attribute->dev_attr.show = sm_attr_show;