qa: add script to test how libceph handles huge auth tickets

Signed-off-by: Ilya Dryomov <[email protected]>

qa/workunits/rbd/huge-tickets.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+# This is a test for http://tracker.ceph.com/issues/8979 and the fallout
+# from triaging it.  #8979 itself was random crashes on corrupted memory
+# due to a buffer overflow (for tickets larger than 256 bytes), further
+# inspection showed that vmalloced tickets weren't handled correctly as
+# well.
+#
+# What we are doing here is generating three huge keyrings and feeding
+# them to libceph (through 'rbd map' on a scratch image).  Bad kernels
+# will crash reliably either on corrupted memory somewhere or a bad page
+# fault in scatterwalk_pagedone().
+
+set -ex
+
+function generate_keyring() {
+    local user=$1
+    local n=$2
+
+    ceph-authtool -C -n client.$user --cap mon 'allow *' --gen-key /tmp/keyring-$user
+
+    set +x # don't pollute trace with echos
+    echo -en "\tcaps osd = \"allow rwx pool=rbd" >>/tmp/keyring-$user
+    for i in $(seq 1 $n); do
+        echo -n ", allow rwx pool=pool$i" >>/tmp/keyring-$user
+    done
+    echo "\"" >>/tmp/keyring-$user
+    set -x
+}
+
+generate_keyring foo 1000 # ~25K, kmalloc
+generate_keyring bar 20000 # ~500K, vmalloc
+generate_keyring baz 300000 # ~8M, vmalloc + sg chaining
+
+rbd create --size 1 test
+
+for user in {foo,bar,baz}; do
+    ceph auth import -i /tmp/keyring-$user
+    DEV=$(sudo rbd map -n client.$user --keyring /tmp/keyring-$user test)
+    sudo rbd unmap $DEV
+done