From 50387e0798ac2b44e1a5b1625ec71c25ebd4aad6 Mon Sep 17 00:00:00 2001

From: Jessica Yu <jeyu@kernel.org>

Date: Fri, 22 Jun 2018 13:59:29 +0200

Subject: [PATCH 1/5] module: make it clear when we're handling the module copy

 in info->hdr

Git-commit: 81a0abd9f213704fbeeea1550ff202000e3c3cdf

Patch-mainline: v4.19-rc1

References: bsc#1093666

In load_module(), it's not always clear whether we're handling the

temporary module copy in info->hdr (which is freed at the end of

load_module()) or if we're handling the module already allocated and

copied to it's final place. Adding an info->mod field and using it

whenever we're handling the temporary copy makes that explicitly clear.

Signed-off-by: Jessica Yu <jeyu@kernel.org>

Acked-by: Jessica Yu <jeyu@suse.de>

---

 kernel/module.c |   44 ++++++++++++++++++++++----------------------

 1 file changed, 22 insertions(+), 22 deletions(-)

--- a/kernel/module.c

+++ b/kernel/module.c

@@ -302,6 +302,8 @@ int unregister_module_notifier(struct no

 EXPORT_SYMBOL(unregister_module_notifier);

 struct load_info {

+	/* pointer to module in temporary copy, freed at end of load_module() */

+	struct module *mod;

 	Elf_Ehdr *hdr;

 	unsigned long len;

 	Elf_Shdr *sechdrs;

@@ -2935,14 +2937,13 @@ static int rewrite_section_headers(struc

  * search for module section index etc), and do some basic section

  * verification.

  *

- * Return the temporary module pointer (we'll replace it with the final

- * one when we move the module sections around).

+ * Set info->mod to the temporary copy of the module in info->hdr. The final one

+ * will be allocated in move_module().

  */

-static struct module *setup_load_info(struct load_info *info, int flags)

+static int setup_load_info(struct load_info *info, int flags)

 {

 	unsigned int i;

 	int err;

-	struct module *mod;

 	/* Set up the convenience variables */

 	info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;

@@ -2951,7 +2952,7 @@ static struct module *setup_load_info(st

 	err = rewrite_section_headers(info, flags);

 	if (err)

-		return ERR_PTR(err);

+		return err;

 	/* Find internal symbols and strings. */

 	for (i = 1; i < info->hdr->e_shnum; i++) {

@@ -2967,23 +2968,23 @@ static struct module *setup_load_info(st

 	info->index.mod = find_sec(info, ".gnu.linkonce.this_module");

 	if (!info->index.mod) {

 		pr_warn("No module found in object\n");

-		return ERR_PTR(-ENOEXEC);

+		return -ENOEXEC;

 	}

 	/* This is temporary: point mod into copy of data. */

-	mod = (void *)info->sechdrs[info->index.mod].sh_addr;

+	info->mod = (void *)info->sechdrs[info->index.mod].sh_addr;

 	if (info->index.sym == 0) {

-		pr_warn("%s: module has no symbols (stripped?)\n", mod->name);

-		return ERR_PTR(-ENOEXEC);

+		pr_warn("%s: module has no symbols (stripped?)\n", info->mod->name);

+		return -ENOEXEC;

 	}

 	info->index.pcpu = find_pcpusec(info);

 	/* Check module struct version now, before we try to use module. */

-	if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))

-		return ERR_PTR(-ENOEXEC);

+	if (!check_modstruct_version(info->sechdrs, info->index.vers, info->mod))

+		return -ENOEXEC;

-	return mod;

+	return 0;

 }

 static int check_modinfo(struct module *mod, struct load_info *info, int flags)

@@ -3274,25 +3275,24 @@ core_param(module_blacklist, module_blac

 static struct module *layout_and_allocate(struct load_info *info, int flags)

 {

-	/* Module within temporary copy. */

 	struct module *mod;

 	unsigned int ndx;

 	int err;

-	mod = setup_load_info(info, flags);

-	if (IS_ERR(mod))

-		return mod;

+	err = setup_load_info(info, flags);

+	if (err)

+		return ERR_PTR(err);

-	if (blacklisted(mod->name))

+	if (blacklisted(info->mod->name))

 		return ERR_PTR(-EPERM);

-	err = check_modinfo(mod, info, flags);

+	err = check_modinfo(info->mod, info, flags);

 	if (err)

 		return ERR_PTR(err);

 	/* Allow arches to frob section contents and sizes.  */

 	err = module_frob_arch_sections(info->hdr, info->sechdrs,

-					info->secstrings, mod);

+					info->secstrings, info->mod);

 	if (err < 0)

 		return ERR_PTR(err);

@@ -3311,11 +3311,11 @@ static struct module *layout_and_allocat

 	/* Determine total sizes, and put offsets in sh_entsize.  For now

 	   this is done generically; there doesn't appear to be any

 	   special cases for the architectures. */

-	layout_sections(mod, info);

-	layout_symtab(mod, info);

+	layout_sections(info->mod, info);

+	layout_symtab(info->mod, info);

 	/* Allocate and move to the final place */

-	err = move_module(mod, info);

+	err = move_module(info->mod, info);

 	if (err)

 		return ERR_PTR(err);