Commit 31956502 authored by Al Viro's avatar Al Viro

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: default avatarAl Viro <[email protected]>
parent 6548fae2
......@@ -794,6 +794,9 @@ static inline int may_follow_link(struct nameidata *nd)
if (uid_eq(parent->i_uid, inode->i_uid))
return 0;
if (nd->flags & LOOKUP_RCU)
return -ECHILD;
audit_log_link_denied("follow_link", &nd->stack[0].link);
return -EACCES;
}
......
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