5.4-stable review patch. If anyone has any objections, please let me know.
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From: Al Viro viro@zeniv.linux.org.uk
[ Upstream commit a890a2e339b929dbd843328f9a92a1625404fe63 ]
Theoretically it's an oopsable race, but I don't believe one can manage to hit it on real hardware; might become doable on a KVM, but it still won't be easy to attack.
Anyway, it's easy to deal with - since xdr_encode_hyper() is just a call of put_unaligned_be64(), we can put that under ->d_lock and be done with that.
Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Anna Schumaker anna.schumaker@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/nfs4proc.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 7a4d7158c55f2..4e9b63c471af7 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -355,7 +355,9 @@ static void nfs4_setup_readdir(u64 cookie, __be32 *verifier, struct dentry *dent *p++ = htonl(attrs); /* bitmap */ *p++ = htonl(12); /* attribute buffer length */ *p++ = htonl(NF4DIR); + spin_lock(&dentry->d_lock); p = xdr_encode_hyper(p, NFS_FILEID(d_inode(dentry->d_parent))); + spin_unlock(&dentry->d_lock);
readdir->pgbase = (char *)p - (char *)start; readdir->count -= readdir->pgbase;