This is a note to let you know that I've just added the patch titled

/dev/mem: Avoid overwriting "err" in read_mem()

to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: dev-mem-avoid-overwriting-err-in-read_mem.patch and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From b5b38200ebe54879a7264cb6f33821f61c586a7e Mon Sep 17 00:00:00 2001

From: Kees Cook keescook@chromium.org Date: Tue, 27 Mar 2018 14:06:14 -0700 Subject: /dev/mem: Avoid overwriting "err" in read_mem()

From: Kees Cook keescook@chromium.org

commit b5b38200ebe54879a7264cb6f33821f61c586a7e upstream.

Successes in probe_kernel_read() would mask failures in copy_to_user() during read_mem().

Reported-by: Brad Spengler spender@grsecurity.net Fixes: 22ec1a2aea73 ("/dev/mem: Add bounce buffer for copy-out") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook keescook@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/char/mem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -137,7 +137,7 @@ static ssize_t read_mem(struct file *fil

while (count > 0) { unsigned long remaining; - int allowed; + int allowed, probe;

sz = size_inside_page(p, count);

@@ -160,9 +160,9 @@ static ssize_t read_mem(struct file *fil if (!ptr) goto failed;

- err = probe_kernel_read(bounce, ptr, sz); + probe = probe_kernel_read(bounce, ptr, sz); unxlate_dev_mem_ptr(p, ptr); - if (err) + if (probe) goto failed;

remaining = copy_to_user(buf, bounce, sz);

Patches currently in stable-queue which might be from keescook@chromium.org are

queue-4.15/dev-mem-avoid-overwriting-err-in-read_mem.patch