path: root/Documentation/networking
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authorRichard Weinberger <>2015-01-30 20:50:44 +0100
committerDavid S. Miller <>2015-02-02 18:50:00 -0800
commite6b02be81b2ed4b2e667f40050cffa64d6bd0256 (patch)
tree8676411b43107bd31744f6afb3146ea421b207cc /Documentation/networking
parent44ba582beac4ff8e05a15e38548ebf3deb509547 (diff)
Documentation: Update netlink_mmap.txt
Update netlink_mmap.txt wrt. commit 4682a0358639b29cf ("netlink: Always copy on mmap TX."). Signed-off-by: Richard Weinberger <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'Documentation/networking')
1 files changed, 3 insertions, 10 deletions
diff --git a/Documentation/networking/netlink_mmap.txt b/Documentation/networking/netlink_mmap.txt
index c6af4bac5aa8..54f10478e8e3 100644
--- a/Documentation/networking/netlink_mmap.txt
+++ b/Documentation/networking/netlink_mmap.txt
@@ -199,16 +199,9 @@ frame header.
TX limitations
-Kernel processing usually involves validation of the message received by
-user-space, then processing its contents. The kernel must assure that
-userspace is not able to modify the message contents after they have been
-validated. In order to do so, the message is copied from the ring frame
-to an allocated buffer if either of these conditions is false:
-- only a single mapping of the ring exists
-- the file descriptor is not shared between processes
-This means that for threaded programs, the kernel will fall back to copying.
+As of Jan 2015 the message is always copied from the ring frame to an
+allocated buffer due to unresolved security concerns.
+See commit 4682a0358639b29cf ("netlink: Always copy on mmap TX.").