aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2015-10-24 07:19:33 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2015-10-24 07:19:33 +0900
commitef594c421a0f96197f28d205e2ee58a83c1e0e37 (patch)
treee6e2a29742133e472002b7d83ed83c469df785c2
parent37902bc190f1396a8c232783b29ddfcaa4026028 (diff)
parent6d69bb536bac0d403d83db1ca841444981b280cd (diff)
downloadlinux-yocto-ef594c421a0f96197f28d205e2ee58a83c1e0e37.tar.gz
linux-yocto-ef594c421a0f96197f28d205e2ee58a83c1e0e37.tar.bz2
linux-yocto-ef594c421a0f96197f28d205e2ee58a83c1e0e37.zip
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
Pull Ceph fixes from Sage Weil: "Two fixes. One is a stopgap to prevent a stack blowout when users have a deep chain of image clones. (We'll rewrite this code to be non-recursive for the next window, but in the meantime this is a simple fix that avoids a crash.) The second fixes a refcount underflow" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: rbd: prevent kernel stack blow up on rbd map rbd: don't leak parent_spec in rbd_dev_probe_parent()
-rw-r--r--drivers/block/rbd.c69
1 files changed, 39 insertions, 30 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index f5e49b639818..6f26cf38c6f9 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -96,6 +96,8 @@ static int atomic_dec_return_safe(atomic_t *v)
#define RBD_MINORS_PER_MAJOR 256
#define RBD_SINGLE_MAJOR_PART_SHIFT 4
+#define RBD_MAX_PARENT_CHAIN_LEN 16
+
#define RBD_SNAP_DEV_NAME_PREFIX "snap_"
#define RBD_MAX_SNAP_NAME_LEN \
(NAME_MAX - (sizeof (RBD_SNAP_DEV_NAME_PREFIX) - 1))
@@ -426,7 +428,7 @@ static ssize_t rbd_add_single_major(struct bus_type *bus, const char *buf,
size_t count);
static ssize_t rbd_remove_single_major(struct bus_type *bus, const char *buf,
size_t count);
-static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping);
+static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth);
static void rbd_spec_put(struct rbd_spec *spec);
static int rbd_dev_id_to_minor(int dev_id)
@@ -5131,44 +5133,51 @@ out_err:
return ret;
}
-static int rbd_dev_probe_parent(struct rbd_device *rbd_dev)
+/*
+ * @depth is rbd_dev_image_probe() -> rbd_dev_probe_parent() ->
+ * rbd_dev_image_probe() recursion depth, which means it's also the
+ * length of the already discovered part of the parent chain.
+ */
+static int rbd_dev_probe_parent(struct rbd_device *rbd_dev, int depth)
{
struct rbd_device *parent = NULL;
- struct rbd_spec *parent_spec;
- struct rbd_client *rbdc;
int ret;
if (!rbd_dev->parent_spec)
return 0;
- /*
- * We need to pass a reference to the client and the parent
- * spec when creating the parent rbd_dev. Images related by
- * parent/child relationships always share both.
- */
- parent_spec = rbd_spec_get(rbd_dev->parent_spec);
- rbdc = __rbd_get_client(rbd_dev->rbd_client);
- ret = -ENOMEM;
- parent = rbd_dev_create(rbdc, parent_spec, NULL);
- if (!parent)
+ if (++depth > RBD_MAX_PARENT_CHAIN_LEN) {
+ pr_info("parent chain is too long (%d)\n", depth);
+ ret = -EINVAL;
+ goto out_err;
+ }
+
+ parent = rbd_dev_create(rbd_dev->rbd_client, rbd_dev->parent_spec,
+ NULL);
+ if (!parent) {
+ ret = -ENOMEM;
goto out_err;
+ }
+
+ /*
+ * Images related by parent/child relationships always share
+ * rbd_client and spec/parent_spec, so bump their refcounts.
+ */
+ __rbd_get_client(rbd_dev->rbd_client);
+ rbd_spec_get(rbd_dev->parent_spec);
- ret = rbd_dev_image_probe(parent, false);
+ ret = rbd_dev_image_probe(parent, depth);
if (ret < 0)
goto out_err;
+
rbd_dev->parent = parent;
atomic_set(&rbd_dev->parent_ref, 1);
-
return 0;
+
out_err:
- if (parent) {
- rbd_dev_unparent(rbd_dev);
+ rbd_dev_unparent(rbd_dev);
+ if (parent)
rbd_dev_destroy(parent);
- } else {
- rbd_put_client(rbdc);
- rbd_spec_put(parent_spec);
- }
-
return ret;
}
@@ -5286,7 +5295,7 @@ static void rbd_dev_image_release(struct rbd_device *rbd_dev)
* parent), initiate a watch on its header object before using that
* object to get detailed information about the rbd image.
*/
-static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
+static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
{
int ret;
@@ -5304,7 +5313,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
if (ret)
goto err_out_format;
- if (mapping) {
+ if (!depth) {
ret = rbd_dev_header_watch_sync(rbd_dev);
if (ret) {
if (ret == -ENOENT)
@@ -5325,7 +5334,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
* Otherwise this is a parent image, identified by pool, image
* and snap ids - need to fill in names for those ids.
*/
- if (mapping)
+ if (!depth)
ret = rbd_spec_fill_snap_id(rbd_dev);
else
ret = rbd_spec_fill_names(rbd_dev);
@@ -5347,12 +5356,12 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
* Need to warn users if this image is the one being
* mapped and has a parent.
*/
- if (mapping && rbd_dev->parent_spec)
+ if (!depth && rbd_dev->parent_spec)
rbd_warn(rbd_dev,
"WARNING: kernel layering is EXPERIMENTAL!");
}
- ret = rbd_dev_probe_parent(rbd_dev);
+ ret = rbd_dev_probe_parent(rbd_dev, depth);
if (ret)
goto err_out_probe;
@@ -5363,7 +5372,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool mapping)
err_out_probe:
rbd_dev_unprobe(rbd_dev);
err_out_watch:
- if (mapping)
+ if (!depth)
rbd_dev_header_unwatch_sync(rbd_dev);
out_header_name:
kfree(rbd_dev->header_name);
@@ -5426,7 +5435,7 @@ static ssize_t do_rbd_add(struct bus_type *bus,
spec = NULL; /* rbd_dev now owns this */
rbd_opts = NULL; /* rbd_dev now owns this */
- rc = rbd_dev_image_probe(rbd_dev, true);
+ rc = rbd_dev_image_probe(rbd_dev, 0);
if (rc < 0)
goto err_out_rbd_dev;