namei: make may_follow_link() safe in RCU mode
authorAl Viro <viro@zeniv.linux.org.uk>
Fri, 8 May 2015 00:37:40 +0000 (20:37 -0400)
committerAl Viro <viro@zeniv.linux.org.uk>
Mon, 11 May 2015 12:13:13 +0000 (08:13 -0400)
commit31956502dd2c9432523d01373a9dc0e5931cfa1c
tree113687c758ac261f3a72c4027baf0007ab6d5647
parent6548fae2eca6b66c7257af6663fdbdf5a50745fd
namei: make may_follow_link() safe in RCU mode

We *can't* call that audit garbage in RCU mode - it's doing a weird
mix of allocations (GFP_NOFS, immediately followed by GFP_KERNEL)
and I'm not touching that... thing again.

So if this security sclero^Whardening feature gets triggered when
we are in RCU mode, tough - we'll fail with -ECHILD and have
everything restarted in non-RCU mode.  Only to hit the same test
and fail, this time with EACCES and with (oh, rapture) an audit spew
produced.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/namei.c