Commit 2b4bfbe0 authored by Akira Kawata's avatar Akira Kawata Committed by Kees Cook
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fs/binfmt_elf: Refactor load_elf_binary function 



I delete load_addr because it is not used anymore. And I rename
load_addr_set to first_pt_load because it is used only to capture the
first iteration of the loop.

Signed-off-by: default avatarAkira Kawata <akirakawata1@gmail.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220127124014.338760-3-akirakawata1@gmail.com
parent 0da1d500

fs/binfmt_elf.c

+6 −8
Original line number Diff line number Diff line
@@ -824,8 +824,8 @@ static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr, 
static int load_elf_binary(struct linux_binprm *bprm)

{

	struct file *interpreter = NULL; /* to shut gcc up */

	unsigned long load_addr, load_bias = 0, phdr_addr = 0;

	int load_addr_set = 0;

	unsigned long load_bias = 0, phdr_addr = 0;

	int first_pt_load = 1;

	unsigned long error;

	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;

	struct elf_phdr *elf_property_phdata = NULL;
@@ -1075,12 +1075,12 @@ static int load_elf_binary(struct linux_binprm *bprm) 


		vaddr = elf_ppnt->p_vaddr;

		/*

		 * The first time through the loop, load_addr_set is false:

		 * The first time through the loop, first_pt_load is true:

		 * layout will be calculated. Once set, use MAP_FIXED since

		 * we know we've already safely mapped the entire region with

		 * MAP_FIXED_NOREPLACE in the once-per-binary logic following.

		 */

		if (load_addr_set) {

		if (!first_pt_load) {

			elf_flags |= MAP_FIXED;

		} else if (elf_ex->e_type == ET_EXEC) {

			/*
@@ -1171,13 +1171,11 @@ static int load_elf_binary(struct linux_binprm *bprm) 
			goto out_free_dentry;

		}



		if (!load_addr_set) {

			load_addr_set = 1;

			load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);

		if (first_pt_load) {

			first_pt_load = 0;

			if (elf_ex->e_type == ET_DYN) {

				load_bias += error -

				             ELF_PAGESTART(load_bias + vaddr);

				load_addr += load_bias;

				reloc_func_desc = load_bias;

			}

		}