Messages in this thread Patch in this message | | | From | Liao Chang <> | Subject | [PATCH 2/3] RISC-V: use memcpy for kexec_file mode | Date | Sat, 30 Oct 2021 11:18:31 +0800 |
| |
The pointer to buffer loading kernel binaries is in kernel space for kexec_fil mode, When copy_from_user copies data from pointer to a block of memory, it checkes that the pointer is in the user space range, on RISCV-V that is:
static inline bool __access_ok(unsigned long addr, unsigned long size) { return size <= TASK_SIZE && addr <= TASK_SIZE - size; }
and TASK_SIZE is 0x4000000000 for 64-bits, which now causes copy_from_user to reject the access of the field 'buf' of struct kexec_segment that is in range [CONFIG_PAGE_OFFSET - VMALLOC_SIZE, CONFIG_PAGE_OFFSET), is invalid user space pointer.
This patch fixes this issue by skipping access_ok(), use mempcy() instead.
Signed-off-by: Liao Chang <liaochang1@huawei.com> --- arch/riscv/kernel/machine_kexec.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c index e6eca271a4d6..4a5db856919b 100644 --- a/arch/riscv/kernel/machine_kexec.c +++ b/arch/riscv/kernel/machine_kexec.c @@ -65,7 +65,9 @@ machine_kexec_prepare(struct kimage *image) if (image->segment[i].memsz <= sizeof(fdt)) continue; - if (copy_from_user(&fdt, image->segment[i].buf, sizeof(fdt))) + if (image->file_mode) + memcpy(&fdt, image->segment[i].buf, sizeof(fdt)); + else if (copy_from_user(&fdt, image->segment[i].buf, sizeof(fdt))) continue; if (fdt_check_header(&fdt)) -- 2.17.1
| |