Re: [PATCH 27/38] sctp: Copy struct sctp_sock.autoclose to userspace using put_user()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 01/10/2018 06:02 PM, Kees Cook wrote:
From: David Windsor <dave@xxxxxxxxxxxx>

The autoclose field can be copied with put_user(), so there is no need to
use copy_to_user(). In both cases, hardened usercopy is being bypassed
since the size is constant, and not open to runtime manipulation.

This patch is verbatim from Brad Spengler/PaX Team's PAX_USERCOPY
whitelisting code in the last public patch of grsecurity/PaX based on my
understanding of the code. Changes or omissions from the original code are
mine and don't reflect the original grsecurity/PaX code.


Just tried a quick rebase and it looks like this conflicts with
c76f97c99ae6 ("sctp: make use of pre-calculated len")
I don't think we can use put_user if we're copying via the full
len?

Thanks,
Laura

Signed-off-by: David Windsor <dave@xxxxxxxxxxxx>
[kees: adjust commit log]
Cc: Vlad Yasevich <vyasevich@xxxxxxxxx>
Cc: Neil Horman <nhorman@xxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: linux-sctp@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
  net/sctp/socket.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index efbc8f52c531..15491491ec88 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -5011,7 +5011,7 @@ static int sctp_getsockopt_autoclose(struct sock *sk, int len, char __user *optv
  	len = sizeof(int);
  	if (put_user(len, optlen))
  		return -EFAULT;
-	if (copy_to_user(optval, &sctp_sk(sk)->autoclose, sizeof(int)))
+	if (put_user(sctp_sk(sk)->autoclose, (int __user *)optval))
  		return -EFAULT;
  	return 0;
  }





[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux