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);