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authorKelvin Cao <kelvin.cao@microchip.com>2020-01-06 12:03:35 -0700
committerBjorn Helgaas <bhelgaas@google.com>2020-01-15 11:00:39 -0600
commitce7c88600bf8ec0d12cf8e147907f96cd58eeb2e (patch)
treefb70df029e2a5eba8485505d199f138c4f626e42 /drivers/pci/switch
parent4efa1d2e36976d7b26f2e67f4c838330fbc91299 (diff)
PCI/switchtec: Add Gen4 MRPC GAS access permission check
Gen4 hardware provides new MRPC commands to read and write directly from any address in the PCI BAR (which Microsemi refers to as GAS). Since accessing BARs can be dangerous and break the driver, we don't want unprivileged users to have this ability. Therefore, require CAP_SYS_ADMIN for the local and remote GAS access MRPC commands. Privileged processes will already have access to the BAR through the sysfs resource file so this doesn't give userspace any capabilities it didn't already have. [logang@deltatee.com: rework commit message] Link: https://lore.kernel.org/r/20200106190337.2428-11-logang@deltatee.com Signed-off-by: Kelvin Cao <kelvin.cao@microchip.com> Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/switch')
-rw-r--r--drivers/pci/switch/switchtec.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index af85d232d200..92b95e8067c0 100644
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -479,6 +479,12 @@ static ssize_t switchtec_dev_write(struct file *filp, const char __user *data,
rc = -EFAULT;
goto out;
}
+ if (((MRPC_CMD_ID(stuser->cmd) == MRPC_GAS_WRITE) ||
+ (MRPC_CMD_ID(stuser->cmd) == MRPC_GAS_READ)) &&
+ !capable(CAP_SYS_ADMIN)) {
+ rc = -EPERM;
+ goto out;
+ }
data += sizeof(stuser->cmd);
rc = copy_from_user(&stuser->data, data, size - sizeof(stuser->cmd));