From: Eric Dumazet edumazet@google.com
[ Upstream commit 5f1eb1ff58ea122e24adf0bc940f268ed2227462 ]
This is a followup of commit 2558b8039d05 ("net: use a bounce buffer for copying skb->mark")
x86 and powerpc define user_access_begin, meaning that they are not able to perform user copy checks when using user_write_access_begin() / unsafe_copy_to_user() and friends [1]
Instead of waiting bugs to trigger on other arches, add a check_object_size() in put_cmsg() to make sure that new code tested on x86 with CONFIG_HARDENED_USERCOPY=y will perform more security checks.
[1] We can not generically call check_object_size() from unsafe_copy_to_user() because UACCESS is enabled at this point.
Signed-off-by: Eric Dumazet edumazet@google.com Cc: Kees Cook keescook@chromium.org Acked-by: Kees Cook keescook@chromium.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/scm.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/core/scm.c b/net/core/scm.c index 5c356f0dee30c..acb7d776fa6ec 100644 --- a/net/core/scm.c +++ b/net/core/scm.c @@ -229,6 +229,8 @@ int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data) if (msg->msg_control_is_user) { struct cmsghdr __user *cm = msg->msg_control_user;
+ check_object_size(data, cmlen - sizeof(*cm), true); + if (!user_write_access_begin(cm, cmlen)) goto efault;