From f72207a5c0dbaaf6921cf9a6c0d2fd0bc249ea78 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Tue, 11 Jul 2023 11:52:26 +0300 Subject: netdevsim: fix uninitialized data in nsim_dev_trap_fa_cookie_write() The simple_write_to_buffer() function is designed to handle partial writes. It returns negatives on error, otherwise it returns the number of bytes that were able to be copied. This code doesn't check the return properly. We only know that the first byte is written, the rest of the buffer might be uninitialized. There is no need to use the simple_write_to_buffer() function. Partial writes are prohibited by the "if (*ppos != 0)" check at the start of the function. Just use memdup_user() and copy the whole buffer. Fixes: d3cbb907ae57 ("netdevsim: add ACL trap reporting cookie as a metadata") Signed-off-by: Dan Carpenter Reviewed-by: Pavan Chebbi Reviewed-by: Ido Schimmel Link: https://lore.kernel.org/r/7c1f950b-3a7d-4252-82a6-876e53078ef7@moroto.mountain Signed-off-by: Jakub Kicinski --- drivers/net/netdevsim/dev.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'drivers/net/netdevsim') diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c index 6045bece2654..b4d3b9cde8bd 100644 --- a/drivers/net/netdevsim/dev.c +++ b/drivers/net/netdevsim/dev.c @@ -184,13 +184,10 @@ static ssize_t nsim_dev_trap_fa_cookie_write(struct file *file, cookie_len = (count - 1) / 2; if ((count - 1) % 2) return -EINVAL; - buf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); - if (!buf) - return -ENOMEM; - ret = simple_write_to_buffer(buf, count, ppos, data, count); - if (ret < 0) - goto free_buf; + buf = memdup_user(data, count); + if (IS_ERR(buf)) + return PTR_ERR(buf); fa_cookie = kmalloc(sizeof(*fa_cookie) + cookie_len, GFP_KERNEL | __GFP_NOWARN); -- cgit v1.2.3