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authorChris Leech <cleech@redhat.com>2016-06-30 18:32:36 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2016-07-14 04:49:57 +0300
commitfa06883281afaa158b2b350f16c377c448df6b61 (patch)
tree6f41d942268a64f6c64a6a25eb8eb17f4e6f2ec6 /drivers/scsi/libfc/fc_exch.c
parent4b9bc86d5a999e344098303882d6395d39e36c13 (diff)
downloadlinux-fa06883281afaa158b2b350f16c377c448df6b61.tar.xz
libfc: sanity check cpu number extracted from xid
In the receive path libfc extracts a cpu number from the ox_id in the fiber channel header and uses that to do a per_cpu_ptr conversion. If, for some reason, a frame is received with an invalid ox_id, per_cpu_ptr will return an invalid pointer and the libfc receive path will panic the system trying to use it. I'm currently looking at such a case, and I don't yet know why a cpu number > nr_cpu_ids is appearing in an exchange id. But adding a sanity check in libfc prevents a system panic, and seems like good idea when dealing with frames coming in from the network. Signed-off-by: Chris Leech <cleech@redhat.com> Acked-by: Johannes Thumshirn <jth@kernel.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/libfc/fc_exch.c')
-rw-r--r--drivers/scsi/libfc/fc_exch.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index 30f9ef0c0d4f..e72673b0a8fb 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -908,9 +908,17 @@ static struct fc_exch *fc_exch_find(struct fc_exch_mgr *mp, u16 xid)
{
struct fc_exch_pool *pool;
struct fc_exch *ep = NULL;
+ u16 cpu = xid & fc_cpu_mask;
+
+ if (cpu >= nr_cpu_ids || !cpu_possible(cpu)) {
+ printk_ratelimited(KERN_ERR
+ "libfc: lookup request for XID = %d, "
+ "indicates invalid CPU %d\n", xid, cpu);
+ return NULL;
+ }
if ((xid >= mp->min_xid) && (xid <= mp->max_xid)) {
- pool = per_cpu_ptr(mp->pool, xid & fc_cpu_mask);
+ pool = per_cpu_ptr(mp->pool, cpu);
spin_lock_bh(&pool->lock);
ep = fc_exch_ptr_get(pool, (xid - mp->min_xid) >> fc_cpu_order);
if (ep) {