From: Liao Chang liaochang1@huawei.com
[ Upstream commit b7fb4d78a6ade6026d9e5cf438c2a46ab962e032 ]
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 Link: https://lore.kernel.org/r/20220408100914.150110-3-lizhengyu3@huawei.com Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 cbef0fc73afa..df8e24559035 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))