6.9-stable review patch. If anyone has any objections, please let me know.
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From: Ekansh Gupta quic_ekangupt@quicinc.com
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@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.... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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)