module: Move livepatch support to a separate file

No functional change.

This patch migrates livepatch support (i.e. used during module
add/or load and remove/or deletion) from core module code into
kernel/module/livepatch.c. At the moment it contains code to
persist Elf information about a given livepatch module, only.
The new file was added to MAINTAINERS.

Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

diff --git a/MAINTAINERS b/MAINTAINERS
index 5e7778c..6dcd93f 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11360,6 +11360,7 @@ F:      arch/s390/include/asm/livepatch.h
 F:     arch/x86/include/asm/livepatch.h
 F:     include/linux/livepatch.h
 F:     kernel/livepatch/
+F:     kernel/module/livepatch.c
 F:     lib/livepatch/
 F:     samples/livepatch/
 F:     tools/testing/selftests/livepatch/

diff --git a/include/linux/module.h b/include/linux/module.h
index 1e135fd..7ec9715 100644 (file)
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -663,17 +663,14 @@ static inline bool module_requested_async_probing(struct module *module)
        return module && module->async_probe_requested;
 }
 
-#ifdef CONFIG_LIVEPATCH
 static inline bool is_livepatch_module(struct module *mod)
 {
+#ifdef CONFIG_LIVEPATCH
        return mod->klp;
-}
-#else /* !CONFIG_LIVEPATCH */
-static inline bool is_livepatch_module(struct module *mod)
-{
+#else
        return false;
+#endif
 }
-#endif /* CONFIG_LIVEPATCH */
 
 bool is_module_sig_enforced(void);
 void set_module_sig_enforced(void);

diff --git a/kernel/module/Makefile b/kernel/module/Makefile
index cdd5c61..ed3aacb 100644 (file)
--- a/kernel/module/Makefile
+++ b/kernel/module/Makefile
@@ -10,3 +10,4 @@ KCOV_INSTRUMENT_module.o := n
 obj-y += main.o
 obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
 obj-$(CONFIG_MODULE_SIG) += signing.o
+obj-$(CONFIG_LIVEPATCH) += livepatch.o

diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index e0775e6..ad7a444 100644 (file)
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -57,6 +57,28 @@ struct load_info {
 
 int mod_verify_sig(const void *mod, struct load_info *info);
 
+#ifdef CONFIG_LIVEPATCH
+int copy_module_elf(struct module *mod, struct load_info *info);
+void free_module_elf(struct module *mod);
+#else /* !CONFIG_LIVEPATCH */
+static inline int copy_module_elf(struct module *mod, struct load_info *info)
+{
+       return 0;
+}
+
+static inline void free_module_elf(struct module *mod) { }
+#endif /* CONFIG_LIVEPATCH */
+
+static inline bool set_livepatch_module(struct module *mod)
+{
+#ifdef CONFIG_LIVEPATCH
+       mod->klp = true;
+       return true;
+#else
+       return false;
+#endif
+}
+
 #ifdef CONFIG_MODULE_DECOMPRESS
 int module_decompress(struct load_info *info, const void *buf, size_t size);
 void module_decompress_cleanup(struct load_info *info);

diff --git a/kernel/module/livepatch.c b/kernel/module/livepatch.c
new file mode 100644 (file)
index 0000000..486d4ff
--- /dev/null
+++ b/kernel/module/livepatch.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module livepatch support
+ *
+ * Copyright (C) 2016 Jessica Yu <jeyu@redhat.com>
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+/*
+ * Persist Elf information about a module. Copy the Elf header,
+ * section header table, section string table, and symtab section
+ * index from info to mod->klp_info.
+ */
+int copy_module_elf(struct module *mod, struct load_info *info)
+{
+       unsigned int size, symndx;
+       int ret;
+
+       size = sizeof(*mod->klp_info);
+       mod->klp_info = kmalloc(size, GFP_KERNEL);
+       if (!mod->klp_info)
+               return -ENOMEM;
+
+       /* Elf header */
+       size = sizeof(mod->klp_info->hdr);
+       memcpy(&mod->klp_info->hdr, info->hdr, size);
+
+       /* Elf section header table */
+       size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
+       mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
+       if (!mod->klp_info->sechdrs) {
+               ret = -ENOMEM;
+               goto free_info;
+       }
+
+       /* Elf section name string table */
+       size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
+       mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
+       if (!mod->klp_info->secstrings) {
+               ret = -ENOMEM;
+               goto free_sechdrs;
+       }
+
+       /* Elf symbol section index */
+       symndx = info->index.sym;
+       mod->klp_info->symndx = symndx;
+
+       /*
+        * For livepatch modules, core_kallsyms.symtab is a complete
+        * copy of the original symbol table. Adjust sh_addr to point
+        * to core_kallsyms.symtab since the copy of the symtab in module
+        * init memory is freed at the end of do_init_module().
+        */
+       mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long)mod->core_kallsyms.symtab;
+
+       return 0;
+
+free_sechdrs:
+       kfree(mod->klp_info->sechdrs);
+free_info:
+       kfree(mod->klp_info);
+       return ret;
+}
+
+void free_module_elf(struct module *mod)
+{
+       kfree(mod->klp_info->sechdrs);
+       kfree(mod->klp_info->secstrings);
+       kfree(mod->klp_info);
+}

diff --git a/kernel/module/main.c b/kernel/module/main.c
index 5898a1a..9151438 100644 (file)
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2043,81 +2043,6 @@ static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 }
 #endif /*  CONFIG_STRICT_MODULE_RWX */
 
-#ifdef CONFIG_LIVEPATCH
-/*
- * Persist Elf information about a module. Copy the Elf header,
- * section header table, section string table, and symtab section
- * index from info to mod->klp_info.
- */
-static int copy_module_elf(struct module *mod, struct load_info *info)
-{
-       unsigned int size, symndx;
-       int ret;
-
-       size = sizeof(*mod->klp_info);
-       mod->klp_info = kmalloc(size, GFP_KERNEL);
-       if (mod->klp_info == NULL)
-               return -ENOMEM;
-
-       /* Elf header */
-       size = sizeof(mod->klp_info->hdr);
-       memcpy(&mod->klp_info->hdr, info->hdr, size);
-
-       /* Elf section header table */
-       size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
-       mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
-       if (mod->klp_info->sechdrs == NULL) {
-               ret = -ENOMEM;
-               goto free_info;
-       }
-
-       /* Elf section name string table */
-       size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
-       mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
-       if (mod->klp_info->secstrings == NULL) {
-               ret = -ENOMEM;
-               goto free_sechdrs;
-       }
-
-       /* Elf symbol section index */
-       symndx = info->index.sym;
-       mod->klp_info->symndx = symndx;
-
-       /*
-        * For livepatch modules, core_kallsyms.symtab is a complete
-        * copy of the original symbol table. Adjust sh_addr to point
-        * to core_kallsyms.symtab since the copy of the symtab in module
-        * init memory is freed at the end of do_init_module().
-        */
-       mod->klp_info->sechdrs[symndx].sh_addr = \
-               (unsigned long) mod->core_kallsyms.symtab;
-
-       return 0;
-
-free_sechdrs:
-       kfree(mod->klp_info->sechdrs);
-free_info:
-       kfree(mod->klp_info);
-       return ret;
-}
-
-static void free_module_elf(struct module *mod)
-{
-       kfree(mod->klp_info->sechdrs);
-       kfree(mod->klp_info->secstrings);
-       kfree(mod->klp_info);
-}
-#else /* !CONFIG_LIVEPATCH */
-static int copy_module_elf(struct module *mod, struct load_info *info)
-{
-       return 0;
-}
-
-static void free_module_elf(struct module *mod)
-{
-}
-#endif /* CONFIG_LIVEPATCH */
-
 void __weak module_memfree(void *module_region)
 {
        /*
@@ -3092,30 +3017,23 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l
        return 0;
 }
 
-#ifdef CONFIG_LIVEPATCH
 static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
 {
-       if (get_modinfo(info, "livepatch")) {
-               mod->klp = true;
+       if (!get_modinfo(info, "livepatch"))
+               /* Nothing more to do */
+               return 0;
+
+       if (set_livepatch_module(mod)) {
                add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
                pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
-                              mod->name);
-       }
-
-       return 0;
-}
-#else /* !CONFIG_LIVEPATCH */
-static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
-{
-       if (get_modinfo(info, "livepatch")) {
-               pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
-                      mod->name);
-               return -ENOEXEC;
+                               mod->name);
+               return 0;
        }
 
-       return 0;
+       pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
+              mod->name);
+       return -ENOEXEC;
 }
-#endif /* CONFIG_LIVEPATCH */
 
 static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
 {