From: Viresh Kumar Date: Thu, 7 Nov 2019 03:20:25 +0000 (+0530) Subject: RDMA/qib: Validate ->show()/store() callbacks before calling them X-Git-Tag: v5.3.16~17 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bca481bd8eb0ea81c0ff138be96507b46b28b00f;p=thirdparty%2Fkernel%2Fstable.git RDMA/qib: Validate ->show()/store() callbacks before calling them 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 Reviewed-by: Greg Kroah-Hartman Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/infiniband/hw/qib/qib_sysfs.c b/drivers/infiniband/hw/qib/qib_sysfs.c index 905206a0c2d5a..d4f5e8cd438de 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); }