From fe90689fed119cb55ff04e6a1df0817f0a3e9d32 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 5 Aug 2019 15:30:03 -0700 Subject: net: docs: replace IPX in tuntap documentation IPX is no longer supported, but the example in the documentation might useful. Replace it with IPv6. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- Documentation/networking/tuntap.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation/networking') diff --git a/Documentation/networking/tuntap.txt b/Documentation/networking/tuntap.txt index 949d5dcdd9a3..0104830d5075 100644 --- a/Documentation/networking/tuntap.txt +++ b/Documentation/networking/tuntap.txt @@ -204,8 +204,8 @@ Ethernet device, which instead of receiving packets from a physical media, receives them from user space program and instead of sending packets via physical media sends them to the user space program. -Let's say that you configured IPX on the tap0, then whenever -the kernel sends an IPX packet to tap0, it is passed to the application +Let's say that you configured IPv6 on the tap0, then whenever +the kernel sends an IPv6 packet to tap0, it is passed to the application (VTun for example). The application encrypts, compresses and sends it to the other side over TCP or UDP. The application on the other side decompresses and decrypts the data received and writes the packet to the TAP device, -- cgit From 414776621d1006e57e80e6db7fdc3837897aaa64 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 7 Aug 2019 17:03:59 -0700 Subject: net/tls: prevent skb_orphan() from leaking TLS plain text with offload sk_validate_xmit_skb() and drivers depend on the sk member of struct sk_buff to identify segments requiring encryption. Any operation which removes or does not preserve the original TLS socket such as skb_orphan() or skb_clone() will cause clear text leaks. Make the TCP socket underlying an offloaded TLS connection mark all skbs as decrypted, if TLS TX is in offload mode. Then in sk_validate_xmit_skb() catch skbs which have no socket (or a socket with no validation) and decrypted flag set. Note that CONFIG_SOCK_VALIDATE_XMIT, CONFIG_TLS_DEVICE and sk->sk_validate_xmit_skb are slightly interchangeable right now, they all imply TLS offload. The new checks are guarded by CONFIG_TLS_DEVICE because that's the option guarding the sk_buff->decrypted member. Second, smaller issue with orphaning is that it breaks the guarantee that packets will be delivered to device queues in-order. All TLS offload drivers depend on that scheduling property. This means skb_orphan_partial()'s trick of preserving partial socket references will cause issues in the drivers. We need a full orphan, and as a result netem delay/throttling will cause all TLS offload skbs to be dropped. Reusing the sk_buff->decrypted flag also protects from leaking clear text when incoming, decrypted skb is redirected (e.g. by TC). See commit 0608c69c9a80 ("bpf: sk_msg, sock{map|hash} redirect through ULP") for justification why the internal flag is safe. The only location which could leak the flag in is tcp_bpf_sendmsg(), which is taken care of by clearing the previously unused bit. v2: - remove superfluous decrypted mark copy (Willem); - remove the stale doc entry (Boris); - rely entirely on EOR marking to prevent coalescing (Boris); - use an internal sendpages flag instead of marking the socket (Boris). v3 (Willem): - reorganize the can_skb_orphan_partial() condition; - fix the flag leak-in through tcp_bpf_sendmsg. Signed-off-by: Jakub Kicinski Acked-by: Willem de Bruijn Reviewed-by: Boris Pismenny Signed-off-by: David S. Miller --- Documentation/networking/tls-offload.rst | 18 ------------------ 1 file changed, 18 deletions(-) (limited to 'Documentation/networking') diff --git a/Documentation/networking/tls-offload.rst b/Documentation/networking/tls-offload.rst index b70b70dc4524..0dd3f748239f 100644 --- a/Documentation/networking/tls-offload.rst +++ b/Documentation/networking/tls-offload.rst @@ -506,21 +506,3 @@ Drivers should ignore the changes to TLS the device feature flags. These flags will be acted upon accordingly by the core ``ktls`` code. TLS device feature flags only control adding of new TLS connection offloads, old connections will remain active after flags are cleared. - -Known bugs -========== - -skb_orphan() leaks clear text ------------------------------ - -Currently drivers depend on the :c:member:`sk` member of -:c:type:`struct sk_buff ` to identify segments requiring -encryption. Any operation which removes or does not preserve the socket -association such as :c:func:`skb_orphan` or :c:func:`skb_clone` -will cause the driver to miss the packets and lead to clear text leaks. - -Redirects leak clear text -------------------------- - -In the RX direction, if segment has already been decrypted by the device -and it gets redirected or mirrored - clear text will be transmitted out. -- cgit