6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ekansh Gupta <quic_ekangupt@xxxxxxxxxxx>
commit bab2f5e8fd5d2f759db26b78d9db57412888f187 upstream.
Untrusted application with access to only non-secure fastrpc device
node can attach to root_pd or static PDs if it can make the respective
init request. This can cause problems as the untrusted application
can send bad requests to root_pd or static PDs. Add changes to reject
attach to privileged PDs if the request is being made using non-secure
fastrpc device node.
Fixes: 0871561055e6 ("misc: fastrpc: Add support for audiopd")
Cc: stable <stable@xxxxxxxxxx>
Signed-off-by: Ekansh Gupta <quic_ekangupt@xxxxxxxxxxx>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240628114501.14310-7-srinivas.kandagatla@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/misc/fastrpc.c | 22 +++++++++++++++++++---
include/uapi/misc/fastrpc.h | 3 +++
2 files changed, 22 insertions(+), 3 deletions(-)
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -2087,6 +2087,16 @@ err_invoke:
return err;
}
+static int is_attach_rejected(struct fastrpc_user *fl)
+{
+ /* Check if the device node is non-secure */
+ if (!fl->is_secure_dev) {
+ dev_dbg(&fl->cctx->rpdev->dev, "untrusted app trying to attach to privileged DSP PD\n");
+ return -EACCES;
+ }
+ return 0;
+}
+
static long fastrpc_device_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
@@ -2099,13 +2109,19 @@ static long fastrpc_device_ioctl(struct
err = fastrpc_invoke(fl, argp);
break;
case FASTRPC_IOCTL_INIT_ATTACH:
- err = fastrpc_init_attach(fl, ROOT_PD);
+ err = is_attach_rejected(fl);
+ if (!err)
+ err = fastrpc_init_attach(fl, ROOT_PD);
break;
case FASTRPC_IOCTL_INIT_ATTACH_SNS:
- err = fastrpc_init_attach(fl, SENSORS_PD);
+ err = is_attach_rejected(fl);
+ if (!err)
+ err = fastrpc_init_attach(fl, SENSORS_PD);
break;
case FASTRPC_IOCTL_INIT_CREATE_STATIC:
- err = fastrpc_init_create_static_process(fl, argp);
+ err = is_attach_rejected(fl);
+ if (!err)
+ err = fastrpc_init_create_static_process(fl, argp);
break;
case FASTRPC_IOCTL_INIT_CREATE:
err = fastrpc_init_create_process(fl, argp);
--- a/include/uapi/misc/fastrpc.h
+++ b/include/uapi/misc/fastrpc.h
@@ -8,11 +8,14 @@
#define FASTRPC_IOCTL_ALLOC_DMA_BUFF _IOWR('R', 1, struct fastrpc_alloc_dma_buf)
#define FASTRPC_IOCTL_FREE_DMA_BUFF _IOWR('R', 2, __u32)
#define FASTRPC_IOCTL_INVOKE _IOWR('R', 3, struct fastrpc_invoke)
+/* This ioctl is only supported with secure device nodes */
#define FASTRPC_IOCTL_INIT_ATTACH _IO('R', 4)
#define FASTRPC_IOCTL_INIT_CREATE _IOWR('R', 5, struct fastrpc_init_create)
#define FASTRPC_IOCTL_MMAP _IOWR('R', 6, struct fastrpc_req_mmap)
#define FASTRPC_IOCTL_MUNMAP _IOWR('R', 7, struct fastrpc_req_munmap)
+/* This ioctl is only supported with secure device nodes */
#define FASTRPC_IOCTL_INIT_ATTACH_SNS _IO('R', 8)
+/* This ioctl is only supported with secure device nodes */
#define FASTRPC_IOCTL_INIT_CREATE_STATIC _IOWR('R', 9, struct fastrpc_init_create_static)
#define FASTRPC_IOCTL_MEM_MAP _IOWR('R', 10, struct fastrpc_mem_map)
#define FASTRPC_IOCTL_MEM_UNMAP _IOWR('R', 11, struct fastrpc_mem_unmap)
