blob: be68e8f2d80c28c94ce01e5e5ed65a81f22cf3fd [file] [log] [blame]
From 8361fb23992a3ce183b44b4fb10bb57908f02eca Mon Sep 17 00:00:00 2001
From: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
Date: Tue, 10 Mar 2020 13:22:52 +0000
Subject: [PATCH] nvmem: check for NULL reg_read and reg_write before
dereferencing
commit 3c91ef69a3e94f78546b246225ed573fbf1735b4 upstream.
Return -EPERM if reg_read is NULL in bin_attr_nvmem_read() or if
reg_write is NULL in bin_attr_nvmem_write().
This prevents NULL dereferences such as the one described in
03cd45d2e219 ("thunderbolt: Prevent crash if non-active NVMem file is
read")
Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200310132257.23358-10-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/nvmem/nvmem-sysfs.c b/drivers/nvmem/nvmem-sysfs.c
index 9e0c429cd08a..8759c4470012 100644
--- a/drivers/nvmem/nvmem-sysfs.c
+++ b/drivers/nvmem/nvmem-sysfs.c
@@ -56,6 +56,9 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
count = round_down(count, nvmem->word_size);
+ if (!nvmem->reg_read)
+ return -EPERM;
+
rc = nvmem->reg_read(nvmem->priv, pos, buf, count);
if (rc)
@@ -90,6 +93,9 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
count = round_down(count, nvmem->word_size);
+ if (!nvmem->reg_write)
+ return -EPERM;
+
rc = nvmem->reg_write(nvmem->priv, pos, buf, count);
if (rc)
--
2.7.4