linux-kernel - [PATCH 4.9 76/80] libnvdimm, region: fix flush hint detection crash

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

Message-Id: <20170518104837.422373198@linuxfoundation.org>
Date:   Thu, 18 May 2017 12:48:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jeff Moyer <jmoyer@...hat.com>,
        Dan Williams <dan.j.williams@...el.com>
Subject: [PATCH 4.9 76/80] libnvdimm, region: fix flush hint detection crash

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Williams <dan.j.williams@...el.com>

commit bc042fdfbb92b5b13421316b4548e2d6e98eed37 upstream.

In the case where a dimm does not have any associated flush hints the
ndrd->flush_wpq array may be uninitialized leading to crashes with the
following signature:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
 IP: region_visible+0x10f/0x160 [libnvdimm]

 Call Trace:
  internal_create_group+0xbe/0x2f0
  sysfs_create_groups+0x40/0x80
  device_add+0x2d8/0x650
  nd_async_device_register+0x12/0x40 [libnvdimm]
  async_run_entry_fn+0x39/0x170
  process_one_work+0x212/0x6c0
  ? process_one_work+0x197/0x6c0
  worker_thread+0x4e/0x4a0
  kthread+0x10c/0x140
  ? process_one_work+0x6c0/0x6c0
  ? kthread_create_on_node+0x60/0x60
  ret_from_fork+0x31/0x40

Reviewed-by: Jeff Moyer <jmoyer@...hat.com>
Fixes: f284a4f23752 ("libnvdimm: introduce nvdimm_flush() and nvdimm_has_flush()")
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/nvdimm/region_devs.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -968,17 +968,20 @@ EXPORT_SYMBOL_GPL(nvdimm_flush);
  */
 int nvdimm_has_flush(struct nd_region *nd_region)
 {
-	struct nd_region_data *ndrd = dev_get_drvdata(&nd_region->dev);
 	int i;
 
 	/* no nvdimm == flushing capability unknown */
 	if (nd_region->ndr_mappings == 0)
 		return -ENXIO;
 
-	for (i = 0; i < nd_region->ndr_mappings; i++)
-		/* flush hints present, flushing required */
-		if (ndrd_get_flush_wpq(ndrd, i, 0))
+	for (i = 0; i < nd_region->ndr_mappings; i++) {
+		struct nd_mapping *nd_mapping = &nd_region->mapping[i];
+		struct nvdimm *nvdimm = nd_mapping->nvdimm;
+
+		/* flush hints present / available */
+		if (nvdimm->num_flush)
 			return 1;
+	}
 
 	/*
 	 * The platform defines dimm devices without hints, assume