From 490194269665d6d4915a4a5774f002885c5a2d8f Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Fri, 21 Apr 2017 15:35:26 -0700
Subject: [PATCH] module: Pass struct load_info into symbol checks

Since we're already using values from struct load_info, just pass this
pointer in directly and use what's needed as we need it. This allows us
to access future fields in struct load_info too.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jessica Yu <jeyu@redhat.com>
---
 kernel/module.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 4a3665f8f837..ca4509b13400 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1278,12 +1278,13 @@ static u32 resolve_rel_crc(const s32 *crc)
 	return *(u32 *)((void *)crc + *crc);
 }
 
-static int check_version(Elf_Shdr *sechdrs,
-			 unsigned int versindex,
+static int check_version(const struct load_info *info,
 			 const char *symname,
 			 struct module *mod,
 			 const s32 *crc)
 {
+	Elf_Shdr *sechdrs = info->sechdrs;
+	unsigned int versindex = info->index.vers;
 	unsigned int i, num_versions;
 	struct modversion_info *versions;
 
@@ -1326,8 +1327,7 @@ bad_version:
 	return 0;
 }
 
-static inline int check_modstruct_version(Elf_Shdr *sechdrs,
-					  unsigned int versindex,
+static inline int check_modstruct_version(const struct load_info *info,
 					  struct module *mod)
 {
 	const s32 *crc;
@@ -1343,8 +1343,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
 		BUG();
 	}
 	preempt_enable();
-	return check_version(sechdrs, versindex,
-			     VMLINUX_SYMBOL_STR(module_layout), mod, crc);
+	return check_version(info, VMLINUX_SYMBOL_STR(module_layout),
+			     mod, crc);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */
@@ -1358,8 +1358,7 @@ static inline int same_magic(const char *amagic, const char *bmagic,
 	return strcmp(amagic, bmagic) == 0;
 }
 #else
-static inline int check_version(Elf_Shdr *sechdrs,
-				unsigned int versindex,
+static inline int check_version(const struct load_info *info,
 				const char *symname,
 				struct module *mod,
 				const s32 *crc)
@@ -1367,8 +1366,7 @@ static inline int check_version(Elf_Shdr *sechdrs,
 	return 1;
 }
 
-static inline int check_modstruct_version(Elf_Shdr *sechdrs,
-					  unsigned int versindex,
+static inline int check_modstruct_version(const struct load_info *info,
 					  struct module *mod)
 {
 	return 1;
@@ -1404,7 +1402,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 	if (!sym)
 		goto unlock;
 
-	if (!check_version(info->sechdrs, info->index.vers, name, mod, crc)) {
+	if (!check_version(info, name, mod, crc)) {
 		sym = ERR_PTR(-EINVAL);
 		goto getname;
 	}
@@ -2971,7 +2969,7 @@ static struct module *setup_load_info(struct load_info *info, int flags)
 	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))
+	if (!check_modstruct_version(info, mod))
 		return ERR_PTR(-ENOEXEC);
 
 	return mod;