Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.4 61/71] RDMA/qib: Validate ->show()/store() callbacks before calling them | Date | Tue, 10 Dec 2019 17:33:06 -0500 |
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From: Viresh Kumar <viresh.kumar@linaro.org>
[ Upstream commit 7ee23491b39259ae83899dd93b2a29ef0f22f0a7 ]
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> --- drivers/infiniband/hw/qib/qib_sysfs.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/infiniband/hw/qib/qib_sysfs.c b/drivers/infiniband/hw/qib/qib_sysfs.c index 81f56cdff2bc2..3ae82202cdb55 100644 --- 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 kobject *kobj, 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 kobject *kobj, struct qib_pportdata *ppd = container_of(kobj, struct qib_pportdata, pport_kobj); + if (!pattr->store) + return -EIO; + return pattr->store(ppd, buf, len); } -- 2.20.1
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