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misc: fastrpc: Restrict untrusted app to attach to privileged PD

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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: 0871561055 ("misc: fastrpc: Add support for audiopd")
Cc: stable <stable@kernel.org>
Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20240628114501.14310-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ekansh Gupta 2024-06-28 12:45:01 +01:00 committed by Greg Kroah-Hartman
parent a6f2f158f1
commit bab2f5e8fd
2 changed files with 22 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

22
drivers/misc/fastrpc.c
View file

@ -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);

3
include/uapi/misc/fastrpc.h
View file

@ -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)