From: Liao Chang <liaochang1@xxxxxxxxxx>
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@xxxxxxxxxx>
---
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))
--
2.17.1
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