>From 8a0296d040a42950cd64e733f7997203975bc184 Mon Sep 17 00:00:00 2001 From: Alexander Boettcher Date: Fri, 13 Apr 2018 23:37:01 +0200 Subject: [PATCH] mbi: use per segment a separate relocator chunk if elf is non relocatable. If the segments are not dense packed, the original code set up a huge relocator chunk comprising all segments. During the final relocation in grub_relocator_prepare_relocs, the chunk is moved to its desired place and overrides memory which are actually not covered/touched by the specified segments. The overriden memory may contain device memory (vga text mode e.g.), which leads to strange boot behaviour. Signed-off-by: Alexander Boettcher --- grub-core/loader/multiboot_elfxx.c | 57 +++++++++++++++++++++++--------------- 1 file changed, 35 insertions(+), 22 deletions(-) diff --git a/grub-core/loader/multiboot_elfxx.c b/grub-core/loader/multiboot_elfxx.c index 67daf59..539c94a 100644 --- a/grub-core/loader/multiboot_elfxx.c +++ b/grub-core/loader/multiboot_elfxx.c @@ -57,9 +57,9 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld) char *phdr_base; grub_err_t err; grub_relocator_chunk_t ch; - grub_uint32_t load_offset, load_size; + grub_uint32_t load_offset = 0, load_size; int i; - void *source; + void *source = NULL; if (ehdr->e_ident[EI_MAG0] != ELFMAG0 || ehdr->e_ident[EI_MAG1] != ELFMAG1 @@ -83,6 +83,7 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld) #define phdr(i) ((Elf_Phdr *) (phdr_base + (i) * ehdr->e_phentsize)) mld->link_base_addr = ~0; + mld->load_base_addr = ~0; /* Calculate lowest and highest load address. */ for (i = 0; i < ehdr->e_phnum; i++) @@ -97,10 +98,14 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld) return grub_error (GRUB_ERR_BAD_OS, "segment crosses 4 GiB border"); #endif - load_size = highest_load - mld->link_base_addr; + grub_dprintf ("multiboot_loader", "link_base_addr=0x%x, load_base_addr=0x%x, " + "relocatable=%d\n", mld->link_base_addr, + mld->load_base_addr, mld->relocatable); if (mld->relocatable) { + load_size = highest_load - mld->link_base_addr; + if (load_size > mld->max_addr || mld->min_addr > mld->max_addr - load_size) return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or load size"); @@ -108,27 +113,19 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld) mld->min_addr, mld->max_addr - load_size, load_size, mld->align ? mld->align : 1, mld->preference, mld->avoid_efi_boot_services); - } - else - err = grub_relocator_alloc_chunk_addr (GRUB_MULTIBOOT (relocator), &ch, - mld->link_base_addr, load_size); - if (err) - { - grub_dprintf ("multiboot_loader", "Cannot allocate memory for OS image\n"); - return err; - } - - mld->load_base_addr = get_physical_target_address (ch); - source = get_virtual_current_address (ch); + if (err) + { + grub_dprintf ("multiboot_loader", "Cannot allocate memory for OS image\n"); + return err; + } - grub_dprintf ("multiboot_loader", "link_base_addr=0x%x, load_base_addr=0x%x, " - "load_size=0x%x, relocatable=%d\n", mld->link_base_addr, - mld->load_base_addr, load_size, mld->relocatable); + mld->load_base_addr = get_physical_target_address (ch); + source = get_virtual_current_address (ch); - if (mld->relocatable) - grub_dprintf ("multiboot_loader", "align=0x%lx, preference=0x%x, avoid_efi_boot_services=%d\n", - (long) mld->align, mld->preference, mld->avoid_efi_boot_services); + grub_dprintf ("multiboot_loader", "align=0x%lx, preference=0x%x, avoid_efi_boot_services=%d\n", + (long) mld->align, mld->preference, mld->avoid_efi_boot_services); + } /* Load every loadable segment in memory. */ for (i = 0; i < ehdr->e_phnum; i++) @@ -139,7 +136,23 @@ CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld) grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx, memsz=0x%lx, vaddr=0x%lx\n", i, (long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz, (long) phdr(i)->p_vaddr); - load_offset = phdr(i)->p_paddr - mld->link_base_addr; + if (mld->relocatable) + load_offset = phdr(i)->p_paddr - mld->link_base_addr; + else + { + err = grub_relocator_alloc_chunk_addr (GRUB_MULTIBOOT (relocator), &ch, + phdr(i)->p_paddr, phdr(i)->p_memsz); + + if (err) + { + grub_dprintf ("multiboot_loader", "Cannot allocate memory for OS image\n"); + return err; + } + + mld->load_base_addr = grub_min (mld->load_base_addr, get_physical_target_address (ch)); + + source = get_virtual_current_address (ch); + } if (phdr(i)->p_filesz != 0) { -- 2.7.4