From: Dan Carpenter Date: Tue, 11 Jul 2023 08:52:26 +0000 (+0300) Subject: netdevsim: fix uninitialized data in nsim_dev_trap_fa_cookie_write() X-Git-Tag: v6.6.7~2363^2~7 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f72207a5c0dbaaf6921cf9a6c0d2fd0bc249ea78;p=platform%2Fkernel%2Flinux-starfive.git 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 --- diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c index 6045bec..b4d3b9c 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);