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@@ -1,7 +1,12 @@
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#include "elf.h"
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+#include "dragonstub/linux-efi.h"
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#include "dragonstub/linux/align.h"
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+#include "dragonstub/printk.h"
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+#include "dragonstub/types.h"
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+#include "efidef.h"
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#include <efi.h>
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#include <efiapi.h>
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+#include <efidevp.h>
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#include <efilib.h>
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#include <dragonstub/dragonstub.h>
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#include <dragonstub/elfloader.h>
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@@ -189,6 +194,72 @@ static bool check_image_region(u64 base, u64 size)
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return ret;
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}
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+
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+/**
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+ * efi_remap_image_all_rwx - Remap a loaded image with the appropriate permissions
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+ * for code and data
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+ *
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+ * @image_base: the base of the image in memory
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+ * @alloc_size: the size of the area in memory occupied by the image
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+ *
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+ * efi_remap_image() uses the EFI memory attribute protocol to remap the code
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+ * region of the loaded image read-only/executable, and the remainder
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+ * read-write/non-executable. The code region is assumed to start at the base
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+ * of the image, and will therefore cover the PE/COFF header as well.
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+ */
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+void efi_remap_image_all_rwx(unsigned long image_base, unsigned alloc_size)
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+{
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+ efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
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+ efi_memory_attribute_protocol_t *memattr;
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+ efi_status_t status;
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+ u64 attr;
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+
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+ /*
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+ * If the firmware implements the EFI_MEMORY_ATTRIBUTE_PROTOCOL, let's
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+ * invoke it to remap the text/rodata region of the decompressed image
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+ * as read-only and the data/bss region as non-executable.
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+ */
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+ status = efi_bs_call(LocateProtocol, &guid, NULL, (void **)&memattr);
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+ if (status != EFI_SUCCESS)
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+ return;
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+
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+ // Get the current attributes for the entire region
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+ status = memattr->get_memory_attributes(memattr, image_base, alloc_size,
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+ &attr);
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+ if (status != EFI_SUCCESS) {
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+ efi_warn(
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+ "Failed to retrieve memory attributes for image region: 0x%lx\n",
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+ status);
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+ return;
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+ }
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+
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+ efi_debug("Current attributes for image region: 0x%lx\n", attr);
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+
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+ // If the entire region was already mapped as non-exec, clear the
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+ // attribute from the code region. Otherwise, set it on the data
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+ // region.
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+ if (attr & EFI_MEMORY_XP) {
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+ status = memattr->clear_memory_attributes(
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+ memattr, image_base, alloc_size, EFI_MEMORY_XP);
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+ if (status != EFI_SUCCESS)
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+ efi_warn("Failed to remap region executable\n");
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+ }
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+
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+ if (attr & EFI_MEMORY_WP) {
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+ status = memattr->clear_memory_attributes(
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+ memattr, image_base, alloc_size, EFI_MEMORY_WP);
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+ if (status != EFI_SUCCESS)
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+ efi_warn("Failed to remap region writable\n");
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+ }
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+
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+ if (attr & EFI_MEMORY_RP) {
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+ status = memattr->clear_memory_attributes(
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+ memattr, image_base, alloc_size, EFI_MEMORY_RP);
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+ if (status != EFI_SUCCESS)
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+ efi_warn("Failed to remap region readable\n");
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+ }
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+}
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+
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efi_status_t efi_allocate_kernel_memory(const Elf64_Phdr *phdr_start,
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u32 phdrs_nr, u64 *ret_paddr,
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u64 *ret_size, u64 *ret_min_paddr,
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@@ -234,6 +305,8 @@ efi_status_t efi_allocate_kernel_memory(const Elf64_Phdr *phdr_start,
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// zeroed the memory
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memset((void *)(*ret_paddr), 0, mem_size);
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+ efi_remap_image_all_rwx(*ret_paddr, mem_size);
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+
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return EFI_SUCCESS;
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}
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@@ -346,5 +419,15 @@ efi_status_t load_elf(struct payload_info *payload_info)
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payload_info->loaded_size = program_size;
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payload_info->kernel_entry =
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ehdr->e_entry - image_link_base_paddr + program_paddr;
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+
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+ // 处理权限问题
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+
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+ efi_remap_image_all_rwx(program_paddr, program_size);
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+ extern void _start(void);
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+ extern void _image_end(void);
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+ u64 image_size = (u64)&_image_end - (u64)&_start;
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+ efi_debug("image_size: %d\n", image_size);
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+ efi_remap_image_all_rwx((u64)&_start, (image_size + 4095) & ~4095);
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+
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return EFI_SUCCESS;
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}
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