From 5e305b5986dc52122a9368a1461f0c13e1de3fd6 Mon Sep 17 00:00:00 2001 From: Ekansh Gupta Date: Fri, 28 Jun 2024 12:45:01 +0100 Subject: [PATCH] misc: fastrpc: Restrict untrusted app to attach to privileged PD 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 Signed-off-by: Ekansh Gupta Reviewed-by: Dmitry Baryshkov Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20240628114501.14310-7-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/misc/fastrpc.c | 22 +++++++++++++++++++--- include/uapi/misc/fastrpc.h | 3 +++ 2 files changed, 22 insertions(+), 3 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index f0626814d56b9a..bbcbc921f3ab81 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -2087,6 +2087,16 @@ static int fastrpc_req_mem_map(struct fastrpc_user *fl, char __user *argp) 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 file *file, unsigned int cmd, 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); diff --git a/include/uapi/misc/fastrpc.h b/include/uapi/misc/fastrpc.h index f33d914d8f4699..91583690bddc52 100644 --- 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)