This is a note to let you know that I've just added the patch titled
RDMA/qib: Validate ->show()/store() callbacks before calling them
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
rdma-qib-validate-show-store-callbacks-before-calling-them.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7ee23491b39259ae83899dd93b2a29ef0f22f0a7 Mon Sep 17 00:00:00 2001
From: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Date: Thu, 7 Nov 2019 08:50:25 +0530
Subject: RDMA/qib: Validate ->show()/store() callbacks before calling them
From: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
commit 7ee23491b39259ae83899dd93b2a29ef0f22f0a7 upstream.
The permissions of the read-only or write-only sysfs files can be
changed (as root) and the user can then try to read a write-only file or
write to a read-only file which will lead to kernel crash here.
Protect against that by always validating the show/store callbacks.
Link: https://lore.kernel.org/r/d45cc26361a174ae12dbb86c994ef334d257924b.1573096807.git.viresh.kumar@xxxxxxxxxx
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/infiniband/hw/qib/qib_sysfs.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/drivers/infiniband/hw/qib/qib_sysfs.c
+++ b/drivers/infiniband/hw/qib/qib_sysfs.c
@@ -301,6 +301,9 @@ static ssize_t qib_portattr_show(struct
struct qib_pportdata *ppd =
container_of(kobj, struct qib_pportdata, pport_kobj);
+ if (!pattr->show)
+ return -EIO;
+
return pattr->show(ppd, buf);
}
@@ -312,6 +315,9 @@ static ssize_t qib_portattr_store(struct
struct qib_pportdata *ppd =
container_of(kobj, struct qib_pportdata, pport_kobj);
+ if (!pattr->store)
+ return -EIO;
+
return pattr->store(ppd, buf, len);
}
Patches currently in stable-queue which might be from viresh.kumar@xxxxxxxxxx are
queue-4.9/rdma-qib-validate-show-store-callbacks-before-calling-them.patch
