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

1 files changed, 66 insertions, 77 deletions

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)