| From 7ee23491b39259ae83899dd93b2a29ef0f22f0a7 Mon Sep 17 00:00:00 2001 |
| From: Viresh Kumar <viresh.kumar@linaro.org> |
| Date: Thu, 7 Nov 2019 08:50:25 +0530 |
| Subject: RDMA/qib: Validate ->show()/store() callbacks before calling them |
| |
| From: Viresh Kumar <viresh.kumar@linaro.org> |
| |
| 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@linaro.org |
| Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> |
| Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| 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); |
| } |
| |