From: Al Viro Date: Fri, 3 Apr 2015 01:47:49 +0000 (-0400) Subject: p9_client_attach(): set fid->uid correctly X-Git-Tag: firefly_0821_release~176^2~1853^2~65^2~1 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=21c9f5ccb103868c730aec6f8548e144ec397fed;p=firefly-linux-kernel-4.4.55.git p9_client_attach(): set fid->uid correctly it's almost always equal to current_fsuid(), but there's an exception - if the first writeback fid is opened by non-root *and* that happens before root has done any lookups in /, we end up doing attach for root. The current code leaves the resulting FID owned by root from the server POV and by non-root from the client one. Unfortunately, it means that e.g. massive dcache eviction will leave that user buggered - they'll end up redoing walks from / *and* picking that FID every time. As soon as they try to create something, the things will get nasty. Signed-off-by: Al Viro --- diff --git a/net/9p/client.c b/net/9p/client.c index 18583bb89db6..6f4c4c88db84 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -1116,6 +1116,7 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid, fid = NULL; goto error; } + fid->uid = n_uname; req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid, afid ? afid->fid : P9_NOFID, uname, aname, n_uname);