This is a note to let you know that I've just added the patch titled
nvmem: check for NULL reg_read and reg_write before dereferencing
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the char-misc-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From a263682a3c9b9ce7b57fbe0296492d1a73d8be58 Mon Sep 17 00:00:00 2001
From: Nicholas Johnson <nicholas.johnson-opensource@xxxxxxxxxxxxxx>
Date: Tue, 10 Mar 2020 13:22:52 +0000
Subject: nvmem: check for NULL reg_read and reg_write before dereferencing
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@xxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200310132257.23358-10-srinivas.kandagatla@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/nvmem/nvmem-sysfs.c | 6 ++++++
1 file changed, 6 insertions(+)
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)
--
2.25.1
