Commit 5d5f08fd authored by Miaoqian Lin's avatar Miaoqian Lin Committed by Max Filippov
Browse files

xtensa: simdisk: add input size check in proc_write_simdisk 



A malicious user could pass an arbitrarily bad value
to memdup_user_nul(), potentially causing kernel crash.

This follows the same pattern as commit ee767463
("netdevsim: prevent bad user input in nsim_dev_health_break_write()")

Fixes: b6c7e873 ("xtensa: ISS: add host file-based simulated disk")
Fixes: 16e5c1fc ("convert a bunch of open-coded instances of memdup_user_nul()")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMiaoqian Lin <linmq006@gmail.com>
Message-Id: <20250829083015.1992751-1-linmq006@gmail.com>
Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent 038d61fd

arch/xtensa/platforms/iss/simdisk.c

+5 −1
Original line number Diff line number Diff line
@@ -231,10 +231,14 @@ static ssize_t proc_read_simdisk(struct file *file, char __user *buf, 
static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,

			size_t count, loff_t *ppos)

{

	char *tmp = memdup_user_nul(buf, count);

	char *tmp;

	struct simdisk *dev = pde_data(file_inode(file));

	int err;



	if (count == 0 || count > PAGE_SIZE)

		return -EINVAL;



	tmp = memdup_user_nul(buf, count);

	if (IS_ERR(tmp))

		return PTR_ERR(tmp);