linux-kernel - [PATCH v3] firmware_class: fix memory leak

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Sun,  2 May 2010 11:21:21 +0300
From:	Tomas Winkler <tomas.winkler@...el.com>
To:	Greg Kroah-Hartman <gregkh@...e.de>, linux-kernel@...r.kernel.org,
	David Woodhouse <dwmw2@...radead.org>,
	Kay Sievers <kay.sievers@...y.org>
Cc:	David Woodhouse <David.Woodhouse@...el.com>,
	Johannes Berg <johannes@...solutions.net>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	Ming Lei <tom.leiming@...il.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Tomas Winkler <tomas.winkler@...el.com>
Subject: [PATCH v3] firmware_class: fix memory leak - free allocated pages

From: David Woodhouse <David.Woodhouse@...el.com>

fix memory leak introduced by the patch 6e03a201bbe:
firmware: speed up request_firmware()

1. vfree won't release pages there were allocated explicitly and mapped
using vmap. The memory has to be vunmap-ed and the pages needs
to be freed explicitly

2. page array is moved into the 'struct
firmware' so that we can free it from release_firmware()
and not only in fw_dev_release()

The fix doesn't break the firmware load speed.

Cc: Johannes Berg <johannes@...solutions.net>
Cc: Greg Kroah-Hartman <gregkh@...e.de>
Cc: Ming Lei <tom.leiming@...il.com>
Cc: Catalin Marinas <catalin.marinas@....com>
Singed-off-by: Kay Sievers <kay.sievers@...y.org>
Signed-off-by: David Woodhouse <David.Woodhouse@...el.com>
Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
---
V2: fix authorship of the patch
V3: fix const struct firmware breakage

 drivers/base/firmware_class.c |   26 ++++++++++++++++++++------
 include/linux/firmware.h      |    1 +
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 985da11..4c70b91 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -130,6 +130,17 @@ static ssize_t firmware_loading_show(struct device *dev,
 	return sprintf(buf, "%d\n", loading);
 }
 
+static void firmware_free_data(const struct firmware *fw)
+{
+	int i;
+	vunmap(fw->data);
+	if (fw->pages) {
+		for (i = 0; i < PFN_UP(fw->size); i++)
+			__free_page(fw->pages[i]);
+		kfree(fw->pages);
+	}
+}
+
 /* Some architectures don't have PAGE_KERNEL_RO */
 #ifndef PAGE_KERNEL_RO
 #define PAGE_KERNEL_RO PAGE_KERNEL
@@ -162,21 +173,21 @@ static ssize_t firmware_loading_store(struct device *dev,
 			mutex_unlock(&fw_lock);
 			break;
 		}
-		vfree(fw_priv->fw->data);
-		fw_priv->fw->data = NULL;
+		firmware_free_data(fw_priv->fw);
+		memset(fw_priv->fw, 0, sizeof(struct firmware));
+		/* If the pages are not owned by 'struct firmware' */
 		for (i = 0; i < fw_priv->nr_pages; i++)
 			__free_page(fw_priv->pages[i]);
 		kfree(fw_priv->pages);
 		fw_priv->pages = NULL;
 		fw_priv->page_array_size = 0;
 		fw_priv->nr_pages = 0;
-		fw_priv->fw->size = 0;
 		set_bit(FW_STATUS_LOADING, &fw_priv->status);
 		mutex_unlock(&fw_lock);
 		break;
 	case 0:
 		if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
-			vfree(fw_priv->fw->data);
+			vunmap(fw_priv->fw->data);
 			fw_priv->fw->data = vmap(fw_priv->pages,
 						 fw_priv->nr_pages,
 						 0, PAGE_KERNEL_RO);
@@ -184,7 +195,10 @@ static ssize_t firmware_loading_store(struct device *dev,
 				dev_err(dev, "%s: vmap() failed\n", __func__);
 				goto err;
 			}
-			/* Pages will be freed by vfree() */
+			/* Pages are now owned by 'struct firmware' */
+			fw_priv->fw->pages = fw_priv->pages;
+			fw_priv->pages = NULL;
+
 			fw_priv->page_array_size = 0;
 			fw_priv->nr_pages = 0;
 			complete(&fw_priv->completion);
@@ -578,7 +592,7 @@ release_firmware(const struct firmware *fw)
 			if (fw->data == builtin->data)
 				goto free_fw;
 		}
-		vfree(fw->data);
+		firmware_free_data(fw);
 	free_fw:
 		kfree(fw);
 	}
diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index 043811f..53d1e6c 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -12,6 +12,7 @@
 struct firmware {
 	size_t size;
 	const u8 *data;
+	struct page **pages;
 };
 
 struct device;
-- 
1.6.6.1

---------------------------------------------------------------------
Intel Israel (74) Limited

This e-mail and any attachments may contain confidential material for
the sole use of the intended recipient(s). Any review or distribution
by others is strictly prohibited. If you are not the intended
recipient, please contact the sender and delete all copies.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/