From 0153498e9ce97fbf7329b590ddb7a373e33b12e6 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Tue, 8 Jun 2010 14:37:14 -0700 Subject: [PATCH] mboot.c32: don't rely on possibly incomplete fields Since load_end_addr and bss_end_addr may be incomplete, we can't actually use them for information. An alternative would be to actually modify these fields in-memory, but it is unclear if that is permitted by the spec. Signed-off-by: H. Peter Anvin --- com32/mboot/map.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/com32/mboot/map.c b/com32/mboot/map.c index 537741e..0a71d4c 100644 --- a/com32/mboot/map.c +++ b/com32/mboot/map.c @@ -1,7 +1,7 @@ /* ----------------------------------------------------------------------- * * * Copyright 2007-2008 H. Peter Anvin - All Rights Reserved - * Copyright 2009 Intel Corporation; author: H. Peter Anvin + * Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin * * Permission is hereby granted, free of charge, to any person * obtaining a copy of this software and associated documentation @@ -169,7 +169,7 @@ struct multiboot_header *map_image(void *ptr, size_t len) for (i = 0; i < eh->e_phnum; i++) { if (ph->p_type == PT_LOAD || ph->p_type == PT_PHDR) { - /* + /* * This loads at p_paddr, which matches Grub. However, if * e_entry falls within the p_vaddr range of this PHDR, then * adjust it to match the p_paddr range... this is how Grub @@ -272,16 +272,19 @@ struct multiboot_header *map_image(void *ptr, size_t len) */ char *data_ptr; addr_t data_len, bss_len; + addr_t bss_addr; regs.eip = mbh->entry_addr; data_ptr = (char *)mbh - (mbh->header_addr - mbh->load_addr); - + if (mbh->load_end_addr) data_len = mbh->load_end_addr - mbh->load_addr; else data_len = len - mbh_offset + (mbh->header_addr - mbh->load_addr); + bss_addr = mbh->load_addr + data_len; + if (mbh->bss_end_addr) bss_len = mbh->bss_end_addr - mbh->load_end_addr; else @@ -306,12 +309,12 @@ struct multiboot_header *map_image(void *ptr, size_t len) } if (bss_len) if (syslinux_add_memmap - (&mmap, mbh->load_end_addr, bss_len, SMT_ZERO)) { + (&mmap, bss_addr, bss_len, SMT_ZERO)) { error("Failed to map a.out bss\n"); return NULL; } - if (mbh->bss_end_addr > mboot_high_water_mark) - mboot_high_water_mark = mbh->bss_end_addr; + if (bss_addr + bss_len > mboot_high_water_mark) + mboot_high_water_mark = bss_addr + bss_len; } else { error ("Invalid Multiboot image: neither ELF header nor a.out kludge found\n"); -- 2.7.4