From 1039bffd6ae9c75b42b7d148d6c1106134107b66 Mon Sep 17 00:00:00 2001 From: Xie Yuanbin Date: Tue, 28 Jul 2026 03:16:42 +0100 Subject: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set, a user fault may trigger show_pte() without any lock. If another thread in the same process concurrently calls munmap(), the page table pages may be freed while show_pte() is still traversing them, causing a use-after-free in show_pte(). If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table of PMD are freed when show_pte() is running. Acquire mmap_write_lock() around show_pte() for user faults to fix the contention. For user faults, additionally restrict that show_pte() is called only when the addr is a user-space address (addr < TASK_SIZE). This is because the lock of tsk->mm only protects the virtual memory of user address space, furthermore, dumping the page tables of a kernel-space address for user faults is unnecessary and may have security implications. Keep everything unchanged for kernel faults, because the kernel is already in the "oops" state, acquiring a lock may risk a deadlock. Co-developed-by: Qi Xi Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults") Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com Acked-by: Lorenzo Stoakes (ARM) Reviewed-by: Linus Walleij Signed-off-by: Qi Xi Signed-off-by: Xie Yuanbin Signed-off-by: Russell King --- include/uapi/misc/fastrpc.h | 143 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100644 include/uapi/misc/fastrpc.h (limited to 'include/uapi/misc/fastrpc.h') diff --git a/include/uapi/misc/fastrpc.h b/include/uapi/misc/fastrpc.h new file mode 100644 index 000000000..c6e2925f4 --- /dev/null +++ b/include/uapi/misc/fastrpc.h @@ -0,0 +1,143 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ + +#ifndef __QCOM_FASTRPC_H__ +#define __QCOM_FASTRPC_H__ + +#include + +#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) +#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) +#define FASTRPC_IOCTL_INIT_ATTACH_SNS _IO('R', 8) +#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) +#define FASTRPC_IOCTL_GET_DSP_INFO _IOWR('R', 13, struct fastrpc_ioctl_capability) + +/** + * enum fastrpc_map_flags - control flags for mapping memory on DSP user process + * @FASTRPC_MAP_STATIC: Map memory pages with RW- permission and CACHE WRITEBACK. + * The driver is responsible for cache maintenance when passed + * the buffer to FastRPC calls. Same virtual address will be + * assigned for subsequent FastRPC calls. + * @FASTRPC_MAP_RESERVED: Reserved + * @FASTRPC_MAP_FD: Map memory pages with RW- permission and CACHE WRITEBACK. + * Mapping tagged with a file descriptor. User is responsible for + * CPU and DSP cache maintenance for the buffer. Get virtual address + * of buffer on DSP using HAP_mmap_get() and HAP_mmap_put() APIs. + * @FASTRPC_MAP_FD_DELAYED: Mapping delayed until user call HAP_mmap() and HAP_munmap() + * functions on DSP. It is useful to map a buffer with cache modes + * other than default modes. User is responsible for CPU and DSP + * cache maintenance for the buffer. + * @FASTRPC_MAP_FD_NOMAP: This flag is used to skip CPU mapping, + * otherwise behaves similar to FASTRPC_MAP_FD_DELAYED flag. + * @FASTRPC_MAP_MAX: max count for flags + * + */ +enum fastrpc_map_flags { + FASTRPC_MAP_STATIC = 0, + FASTRPC_MAP_RESERVED, + FASTRPC_MAP_FD = 2, + FASTRPC_MAP_FD_DELAYED, + FASTRPC_MAP_FD_NOMAP = 16, + FASTRPC_MAP_MAX, +}; + +enum fastrpc_proc_attr { + /* Macro for Debug attr */ + FASTRPC_MODE_DEBUG = (1 << 0), + /* Macro for Ptrace */ + FASTRPC_MODE_PTRACE = (1 << 1), + /* Macro for CRC Check */ + FASTRPC_MODE_CRC = (1 << 2), + /* Macro for Unsigned PD */ + FASTRPC_MODE_UNSIGNED_MODULE = (1 << 3), + /* Macro for Adaptive QoS */ + FASTRPC_MODE_ADAPTIVE_QOS = (1 << 4), + /* Macro for System Process */ + FASTRPC_MODE_SYSTEM_PROCESS = (1 << 5), + /* Macro for Prvileged Process */ + FASTRPC_MODE_PRIVILEGED = (1 << 6), +}; + +/* Fastrpc attribute for memory protection of buffers */ +#define FASTRPC_ATTR_SECUREMAP (1) + +struct fastrpc_invoke_args { + __u64 ptr; + __u64 length; + __s32 fd; + __u32 attr; +}; + +struct fastrpc_invoke { + __u32 handle; + __u32 sc; + __u64 args; +}; + +struct fastrpc_init_create { + __u32 filelen; /* elf file length */ + __s32 filefd; /* fd for the file */ + __u32 attrs; + __u32 siglen; + __u64 file; /* pointer to elf file */ +}; + +struct fastrpc_init_create_static { + __u32 namelen; /* length of pd process name */ + __u32 memlen; + __u64 name; /* pd process name */ +}; + +struct fastrpc_alloc_dma_buf { + __s32 fd; /* fd */ + __u32 flags; /* flags to map with */ + __u64 size; /* size */ +}; + +struct fastrpc_req_mmap { + __s32 fd; + __u32 flags; /* flags for dsp to map with */ + __u64 vaddrin; /* optional virtual address */ + __u64 size; /* size */ + __u64 vaddrout; /* dsp virtual address */ +}; + +struct fastrpc_mem_map { + __s32 version; + __s32 fd; /* fd */ + __s32 offset; /* buffer offset */ + __u32 flags; /* flags defined in enum fastrpc_map_flags */ + __u64 vaddrin; /* buffer virtual address */ + __u64 length; /* buffer length */ + __u64 vaddrout; /* [out] remote virtual address */ + __s32 attrs; /* buffer attributes used for SMMU mapping */ + __s32 reserved[4]; +}; + +struct fastrpc_req_munmap { + __u64 vaddrout; /* address to unmap */ + __u64 size; /* size */ +}; + +struct fastrpc_mem_unmap { + __s32 vesion; + __s32 fd; /* fd */ + __u64 vaddr; /* remote process (dsp) virtual address */ + __u64 length; /* buffer size */ + __s32 reserved[5]; +}; + +struct fastrpc_ioctl_capability { + __u32 unused; /* deprecated, ignored by the kernel */ + __u32 attribute_id; + __u32 capability; /* dsp capability */ + __u32 reserved[4]; +}; + +#endif /* __QCOM_FASTRPC_H__ */ -- cgit v1.3.1