diff options
| author | Kelvin Cao <kelvin.cao@microchip.com> | 2020-01-06 22:03:35 +0300 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2020-01-15 20:00:39 +0300 |
| commit | ce7c88600bf8ec0d12cf8e147907f96cd58eeb2e (patch) | |
| tree | fb70df029e2a5eba8485505d199f138c4f626e42 | |
| parent | 4efa1d2e36976d7b26f2e67f4c838330fbc91299 (diff) | |
| download | linux-ce7c88600bf8ec0d12cf8e147907f96cd58eeb2e.tar.xz | |
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>
| -rw-r--r-- | drivers/pci/switch/switchtec.c | 6 | ||||
| -rw-r--r-- | include/linux/switchtec.h | 5 |
2 files changed, 11 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)); diff --git a/include/linux/switchtec.h b/include/linux/switchtec.h index e85155244135..082f1d51957a 100644 --- a/include/linux/switchtec.h +++ b/include/linux/switchtec.h @@ -21,6 +21,11 @@ #define SWITCHTEC_EVENT_FATAL BIT(4) #define SWITCHTEC_DMA_MRPC_EN BIT(0) + +#define MRPC_GAS_READ 0x29 +#define MRPC_GAS_WRITE 0x87 +#define MRPC_CMD_ID(x) ((x) & 0xffff) + enum { SWITCHTEC_GAS_MRPC_OFFSET = 0x0000, SWITCHTEC_GAS_TOP_CFG_OFFSET = 0x1000, |