Commit d08b6a56 authored by Sergey Shtylyov's avatar Sergey Shtylyov Committed by Chen Jun
Browse files

of: module: prevent NULL pointer dereference in vsnprintf() 

mainline inclusion
from mainline-v6.9-rc3
commit a1aa5390cc912934fee76ce80af5f940452fa987
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QG8R
CVE: CVE-2024-35878

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a1aa5390cc912934fee76ce80af5f940452fa987



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

In of_modalias(), we can get passed the str and len parameters which would
cause a kernel oops in vsnprintf() since it only allows passing a NULL ptr
when the length is also 0. Also, we need to filter out the negative values
of the len parameter as these will result in a really huge buffer since
snprintf() takes size_t parameter while ours is ssize_t...

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.

Signed-off-by: default avatarSergey Shtylyov <s.shtylyov@omp.ru>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1d211023-3923-685b-20f0-f3f90ea56e1f@omp.ru


Signed-off-by: default avatarRob Herring <robh@kernel.org>

Conflicts:
	drivers/of/device.c
	drivers/of/module.c
[chenjun: context conflicts. of_modalias() is not extracted from
of_device_get_modalias().]
Signed-off-by: default avatarChen Jun <chenjun102@huawei.com>
parent c93f7899

drivers/of/device.c

+8 −0
Original line number Diff line number Diff line
@@ -226,6 +226,14 @@ static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len 
	if ((!dev) || (!dev->of_node))

		return -ENODEV;



	/*

	 * Prevent a kernel oops in vsnprintf() -- it only allows passing a

	 * NULL ptr when the length is also 0. Also filter out the negative

	 * lengths...

	 */

	if ((len > 0 && !str) || len < 0)

		return -EINVAL;



	/* Name & Type */

	/* %p eats all alphanum characters, so %c must be used here */

	csize = snprintf(str, len, "of:N%pOFn%c%s", dev->of_node, 'T',