diff options
| author | Vasily Averin <vvs@virtuozzo.com> | 2019-02-21 18:23:17 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2019-03-06 19:26:45 -0500 |
| commit | 08b11eaccfcf86a3bac6755625d933ac15ccc27a (patch) | |
| tree | 2de1b9f75412613fc834810ff9bcec90e78c7792 /drivers/scsi | |
| parent | 038d710fca5bb149d3af2e0b71f1284f8430a979 (diff) | |
scsi: libiscsi: fall back to sendmsg for slab pages
In "XFS over network block device" scenario XFS can create IO requests with
slab-based XFS metadata. During processing such requests tcp_sendpage() can
merge skb fragments with neighbour slab objects.
If receiving side is located on the same host tcp_recvmsg() can trigger
BUG_ON in hardening check and crash the host with following message:
usercopy: kernel memory exposure attempt detected
from XXXXXXXX (kmalloc-512) (1024 bytes)
This patch redirect such requests from sednpage to sendmsg path. The
problem is similar to one described in recent commit 7e241f647dc7
("libceph: fall back to sendmsg for slab pages")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi')
| -rw-r--r-- | drivers/scsi/libiscsi_tcp.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c index 9923e9e3b884..c3fe3f3a78f5 100644 --- a/drivers/scsi/libiscsi_tcp.c +++ b/drivers/scsi/libiscsi_tcp.c @@ -129,12 +129,17 @@ static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv) BUG_ON(sg->length == 0); /* + * We always map for the recv path. + * * If the page count is greater than one it is ok to send * to the network layer's zero copy send path. If not we - * have to go the slow sendmsg path. We always map for the - * recv path. + * have to go the slow sendmsg path. + * + * Same goes for slab pages: skb_can_coalesce() allows + * coalescing neighboring slab objects into a single frag which + * triggers one of hardened usercopy checks. */ - if (page_count(sg_page(sg)) >= 1 && !recv) + if (!recv && page_count(sg_page(sg)) >= 1 && !PageSlab(sg_page(sg))) return; if (recv) { |