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authorMike Snitzer <snitzer@redhat.com>2018-09-17 18:38:47 +0300
committerMike Snitzer <snitzer@redhat.com>2018-09-18 05:46:49 +0300
commitb592211c33f745af67a3271ce77c10fc1e6d6241 (patch)
treee7d3f619055d7c721b4a32b3af14e070cfd21c4e /drivers/md/dm-mpath.c
parent013ad043906b2befd4a9bfb06219ed9fedd92716 (diff)
downloadlinux-b592211c33f745af67a3271ce77c10fc1e6d6241.tar.xz
dm mpath: fix attached_handler_name leak and dangling hw_handler_name pointer
Commit e8f74a0f0011 ("dm mpath: eliminate need to use scsi_device_from_queue") introduced 2 regressions: 1) memory leak occurs if attached_handler_name is not assigned to m->hw_handler_name 2) m->hw_handler_name can become a dangling pointer if the RETAIN_ATTACHED_HW_HANDLER flag is set and scsi_dh_attach() returns -EBUSY. Fix both of these by clearing 'attached_handler_name' pointer passed to setup_scsi_dh() after it is assigned to m->hw_handler_name. And if setup_scsi_dh() doesn't consume 'attached_handler_name' parse_path() will kfree() it. Fixes: e8f74a0f0011 ("dm mpath: eliminate need to use scsi_device_from_queue") Cc: stable@vger.kernel.org # 4.16+ Reported-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-mpath.c')
-rw-r--r--drivers/md/dm-mpath.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index d94ba6f72ff5..419362c2d8ac 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -806,19 +806,19 @@ static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg,
}
static int setup_scsi_dh(struct block_device *bdev, struct multipath *m,
- const char *attached_handler_name, char **error)
+ const char **attached_handler_name, char **error)
{
struct request_queue *q = bdev_get_queue(bdev);
int r;
if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) {
retain:
- if (attached_handler_name) {
+ if (*attached_handler_name) {
/*
* Clear any hw_handler_params associated with a
* handler that isn't already attached.
*/
- if (m->hw_handler_name && strcmp(attached_handler_name, m->hw_handler_name)) {
+ if (m->hw_handler_name && strcmp(*attached_handler_name, m->hw_handler_name)) {
kfree(m->hw_handler_params);
m->hw_handler_params = NULL;
}
@@ -830,7 +830,8 @@ retain:
* handler instead of the original table passed in.
*/
kfree(m->hw_handler_name);
- m->hw_handler_name = attached_handler_name;
+ m->hw_handler_name = *attached_handler_name;
+ *attached_handler_name = NULL;
}
}
@@ -867,7 +868,7 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
struct pgpath *p;
struct multipath *m = ti->private;
struct request_queue *q;
- const char *attached_handler_name;
+ const char *attached_handler_name = NULL;
/* we need at least a path arg */
if (as->argc < 1) {
@@ -890,7 +891,7 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL);
if (attached_handler_name || m->hw_handler_name) {
INIT_DELAYED_WORK(&p->activate_path, activate_path_work);
- r = setup_scsi_dh(p->path.dev->bdev, m, attached_handler_name, &ti->error);
+ r = setup_scsi_dh(p->path.dev->bdev, m, &attached_handler_name, &ti->error);
if (r) {
dm_put_device(ti, p->path.dev);
goto bad;
@@ -905,6 +906,7 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
return p;
bad:
+ kfree(attached_handler_name);
free_pgpath(p);
return ERR_PTR(r);
}