Merge tag 'modules-for-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux

Pull modules updates from Jessica Yu:
 "Summary of modules changes for the 4.19 merge window:

   - Fix modules kallsyms for livepatch. Livepatch modules can have
     SHN_UNDEF symbols in their module symbol tables for later symbol
     resolution, but kallsyms shouldn't be returning these symbols

   - Some code cleanups and minor reshuffling in load_module() were done
     to log the module name when module signature verification fails"

* tag 'modules-for-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  kernel/module: Use kmemdup to replace kmalloc+memcpy
  ARM: module: fix modsign build error
  modsign: log module name in the event of an error
  module: replace VMLINUX_SYMBOL_STR() with __stringify() or string literal
  module: print sensible error code
  module: setup load info before module_sig_check()
  module: make it clear when we're handling the module copy in info->hdr
  module: exclude SHN_UNDEF symbols from kallsyms api

5 files changed, 100 insertions, 85 deletions

diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h
index 89ad0596033a..9e81b7c498d8 100644
--- a/arch/arm/include/asm/module.h
+++ b/arch/arm/include/asm/module.h
@@ -34,6 +34,7 @@ struct mod_arch_specific {
 #endif
 };
 
+struct module;
 u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val);
 
 /*
diff --git a/include/linux/module.h b/include/linux/module.h
index d44df9b2c131..f807f15bebbe 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -266,7 +266,7 @@ extern int modules_disabled; /* for sysctl */
 /* Get/put a kernel symbol (calls must be symmetric) */
 void *__symbol_get(const char *symbol);
 void *__symbol_get_gpl(const char *symbol);
-#define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x))))
+#define symbol_get(x) ((typeof(&x))(__symbol_get(__stringify(x))))
 
 /* modules using other modules: kdb wants to see this. */
 struct module_use {
@@ -575,7 +575,7 @@ extern void __noreturn __module_put_and_exit(struct module *mod,
 #ifdef CONFIG_MODULE_UNLOAD
 int module_refcount(struct module *mod);
 void __symbol_put(const char *symbol);
-#define symbol_put(x) __symbol_put(VMLINUX_SYMBOL_STR(x))
+#define symbol_put(x) __symbol_put(__stringify(x))
 void symbol_put_addr(void *addr);
 
 /* Sometimes we know we already have a refcount, and it's easier not
diff --git a/kernel/module-internal.h b/kernel/module-internal.h
index 915e123a430f..79c9be2dbbe9 100644
--- a/kernel/module-internal.h
+++ b/kernel/module-internal.h
@@ -9,4 +9,27 @@
  * 2 of the Licence, or (at your option) any later version.
  */
 
-extern int mod_verify_sig(const void *mod, unsigned long *_modlen);
+#include <linux/elf.h>
+#include <asm/module.h>
+
+struct load_info {
+	const char *name;
+	/* pointer to module in temporary copy, freed at end of load_module() */
+	struct module *mod;
+	Elf_Ehdr *hdr;
+	unsigned long len;
+	Elf_Shdr *sechdrs;
+	char *secstrings, *strtab;
+	unsigned long symoffs, stroffs;
+	struct _ddebug *debug;
+	unsigned int num_debug;
+	bool sig_ok;
+#ifdef CONFIG_KALLSYMS
+	unsigned long mod_kallsyms_init_off;
+#endif
+	struct {
+		unsigned int sym, str, mod, vers, info, pcpu;
+	} index;
+};
+
+extern int mod_verify_sig(const void *mod, struct load_info *info);
diff --git a/kernel/module.c b/kernel/module.c
index a7615d661910..b046a32520d8 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -307,24 +307,6 @@ int unregister_module_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_module_notifier);
 
-struct load_info {
-	const char *name;
-	Elf_Ehdr *hdr;
-	unsigned long len;
-	Elf_Shdr *sechdrs;
-	char *secstrings, *strtab;
-	unsigned long symoffs, stroffs;
-	struct _ddebug *debug;
-	unsigned int num_debug;
-	bool sig_ok;
-#ifdef CONFIG_KALLSYMS
-	unsigned long mod_kallsyms_init_off;
-#endif
-	struct {
-		unsigned int sym, str, mod, vers, info, pcpu;
-	} index;
-};
-
 /*
  * We require a truly strong try_module_get(): 0 means success.
  * Otherwise an error is returned due to ongoing or failed
@@ -1339,14 +1321,12 @@ static inline int check_modstruct_version(const struct load_info *info,
 	 * locking is necessary -- use preempt_disable() to placate lockdep.
 	 */
 	preempt_disable();
-	if (!find_symbol(VMLINUX_SYMBOL_STR(module_layout), NULL,
-			 &crc, true, false)) {
+	if (!find_symbol("module_layout", NULL, &crc, true, false)) {
 		preempt_enable();
 		BUG();
 	}
 	preempt_enable();
-	return check_version(info, VMLINUX_SYMBOL_STR(module_layout),
-			     mod, crc);
+	return check_version(info, "module_layout", mod, crc);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */
@@ -2059,21 +2039,19 @@ static int copy_module_elf(struct module *mod, struct load_info *info)
 
 	/* Elf section header table */
 	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
-	mod->klp_info->sechdrs = kmalloc(size, GFP_KERNEL);
+	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
 	if (mod->klp_info->sechdrs == NULL) {
 		ret = -ENOMEM;
 		goto free_info;
 	}
-	memcpy(mod->klp_info->sechdrs, info->sechdrs, size);
 
 	/* Elf section name string table */
 	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
-	mod->klp_info->secstrings = kmalloc(size, GFP_KERNEL);
+	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
 	if (mod->klp_info->secstrings == NULL) {
 		ret = -ENOMEM;
 		goto free_sechdrs;
 	}
-	memcpy(mod->klp_info->secstrings, info->secstrings, size);
 
 	/* Elf symbol section index */
 	symndx = info->index.sym;
@@ -2282,9 +2260,9 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)
 			if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
 				break;
 
-			pr_warn("%s: Unknown symbol %s (err %li)\n",
-				mod->name, name, PTR_ERR(ksym));
 			ret = PTR_ERR(ksym) ?: -ENOENT;
+			pr_warn("%s: Unknown symbol %s (err %d)\n",
+				mod->name, name, ret);
 			break;
 
 		default:
@@ -2486,7 +2464,11 @@ static char *get_modinfo(struct load_info *info, const char *tag)
 	Elf_Shdr *infosec = &info->sechdrs[info->index.info];
 	unsigned long size = infosec->sh_size;
 
-	for (p = (char *)infosec->sh_addr; p; p = next_string(p, &size)) {
+	/*
+	 * get_modinfo() calls made before rewrite_section_headers()
+	 * must use sh_offset, as sh_addr isn't set!
+	 */
+	for (p = (char *)info->hdr + infosec->sh_offset; p; p = next_string(p, &size)) {
 		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 			return p + taglen + 1;
 	}
@@ -2774,7 +2756,7 @@ static int module_sig_check(struct load_info *info, int flags)
 	    memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
 		/* We truncate the module to discard the signature */
 		info->len -= markerlen;
-		err = mod_verify_sig(mod, &info->len);
+		err = mod_verify_sig(mod, info);
 	}
 
 	if (!err) {
@@ -2926,17 +2908,7 @@ static int rewrite_section_headers(struct load_info *info, int flags)
 	}
 
 	/* Track but don't keep modinfo and version sections. */
-	if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
-		info->index.vers = 0; /* Pretend no __versions section! */
-	else
-		info->index.vers = find_sec(info, "__versions");
 	info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
-
-	info->index.info = find_sec(info, ".modinfo");
-	if (!info->index.info)
-		info->name = "(missing .modinfo section)";
-	else
-		info->name = get_modinfo(info, "name");
 	info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
 
 	return 0;
@@ -2947,23 +2919,24 @@ static int rewrite_section_headers(struct load_info *info, int flags)
  * 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;
 	info->secstrings = (void *)info->hdr
 		+ info->sechdrs[info->hdr->e_shstrndx].sh_offset;
 
-	err = rewrite_section_headers(info, flags);
-	if (err)
-		return ERR_PTR(err);
+	/* Try to find a name early so we can log errors with a module name */
+	info->index.info = find_sec(info, ".modinfo");
+	if (!info->index.info)
+		info->name = "(missing .modinfo section)";
+	else
+		info->name = get_modinfo(info, "name");
 
 	/* Find internal symbols and strings. */
 	for (i = 1; i < info->hdr->e_shnum; i++) {
@@ -2976,34 +2949,35 @@ static struct module *setup_load_info(struct load_info *info, int flags)
 		}
 	}
 
+	if (info->index.sym == 0) {
+		pr_warn("%s: module has no symbols (stripped?)\n", info->name);
+		return -ENOEXEC;
+	}
+
 	info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
 	if (!info->index.mod) {
 		pr_warn("%s: No module found in object\n",
 			info->name ?: "(missing .modinfo name field)");
-		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->hdr + info->sechdrs[info->index.mod].sh_offset;
 
 	/*
-	 * If we didn't load the .modinfo 'name' field, fall back to
+	 * If we didn't load the .modinfo 'name' field earlier, fall back to
 	 * on-disk struct mod 'name' field.
 	 */
 	if (!info->name)
-		info->name = mod->name;
+		info->name = info->mod->name;
 
-	if (info->index.sym == 0) {
-		pr_warn("%s: module has no symbols (stripped?)\n", info->name);
-		return ERR_PTR(-ENOEXEC);
-	}
+	if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
+		info->index.vers = 0; /* Pretend no __versions section! */
+	else
+		info->index.vers = find_sec(info, "__versions");
 
 	info->index.pcpu = find_pcpusec(info);
 
-	/* Check module struct version now, before we try to use module. */
-	if (!check_modstruct_version(info, mod))
-		return ERR_PTR(-ENOEXEC);
-
-	return mod;
+	return 0;
 }
 
 static int check_modinfo(struct module *mod, struct load_info *info, int flags)
@@ -3298,25 +3272,17 @@ core_param(module_blacklist, module_blacklist, charp, 0400);
 
 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;
-
-	if (blacklisted(info->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);
 
@@ -3335,11 +3301,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
 	/* 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);
 
@@ -3657,17 +3623,36 @@ static int load_module(struct load_info *info, const char __user *uargs,
 		       int flags)
 {
 	struct module *mod;
-	long err;
+	long err = 0;
 	char *after_dashes;
 
+	err = elf_header_check(info);
+	if (err)
+		goto free_copy;
+
+	err = setup_load_info(info, flags);
+	if (err)
+		goto free_copy;
+
+	if (blacklisted(info->name)) {
+		err = -EPERM;
+		goto free_copy;
+	}
+
 	err = module_sig_check(info, flags);
 	if (err)
 		goto free_copy;
 
-	err = elf_header_check(info);
+	err = rewrite_section_headers(info, flags);
 	if (err)
 		goto free_copy;
 
+	/* Check module struct version now, before we try to use module. */
+	if (!check_modstruct_version(info, info->mod)) {
+		err = -ENOEXEC;
+		goto free_copy;
+	}
+
 	/* Figure out module layout, and allocate all the memory. */
 	mod = layout_and_allocate(info, flags);
 	if (IS_ERR(mod)) {
@@ -4067,7 +4052,7 @@ static unsigned long mod_find_symname(struct module *mod, const char *name)
 
 	for (i = 0; i < kallsyms->num_symtab; i++)
 		if (strcmp(name, symname(kallsyms, i)) == 0 &&
-		    kallsyms->symtab[i].st_info != 'U')
+		    kallsyms->symtab[i].st_shndx != SHN_UNDEF)
 			return kallsyms->symtab[i].st_value;
 	return 0;
 }
@@ -4113,6 +4098,10 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
 		for (i = 0; i < kallsyms->num_symtab; i++) {
+
+			if (kallsyms->symtab[i].st_shndx == SHN_UNDEF)
+				continue;
+
 			ret = fn(data, symname(kallsyms, i),
 				 mod, kallsyms->symtab[i].st_value);
 			if (ret != 0)
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index 937c844bee4a..f2075ce8e4b3 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -45,10 +45,10 @@ struct module_signature {
 /*
  * Verify the signature on a module.
  */
-int mod_verify_sig(const void *mod, unsigned long *_modlen)
+int mod_verify_sig(const void *mod, struct load_info *info)
 {
 	struct module_signature ms;
-	size_t modlen = *_modlen, sig_len;
+	size_t sig_len, modlen = info->len;
 
 	pr_devel("==>%s(,%zu)\n", __func__, modlen);
 
@@ -62,10 +62,11 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
 	if (sig_len >= modlen)
 		return -EBADMSG;
 	modlen -= sig_len;
-	*_modlen = modlen;
+	info->len = modlen;
 
 	if (ms.id_type != PKEY_ID_PKCS7) {
-		pr_err("Module is not signed with expected PKCS#7 message\n");
+		pr_err("%s: Module is not signed with expected PKCS#7 message\n",
+		       info->name);
 		return -ENOPKG;
 	}
 
@@ -76,7 +77,8 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
 	    ms.__pad[0] != 0 ||
 	    ms.__pad[1] != 0 ||
 	    ms.__pad[2] != 0) {
-		pr_err("PKCS#7 signature info has unexpected non-zero params\n");
+		pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n",
+		       info->name);
 		return -EBADMSG;
 	}