module: move more elf validity checks to elf_validity_check()

The symbol and strings section validation currently happen in
setup_load_info() but since they are also doing validity checks
move this to elf_validity_check().

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

diff --git a/kernel/module/main.c b/kernel/module/main.c
index fbe62d1..84a7f96 100644 (file)
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1658,6 +1658,8 @@ static int elf_validity_check(struct load_info *info)
        Elf_Shdr *shdr, *strhdr;
        int err;
        unsigned int num_mod_secs = 0, mod_idx;
+       unsigned int num_info_secs = 0, info_idx;
+       unsigned int num_sym_secs = 0, sym_idx;
 
        if (info->len < sizeof(*(info->hdr))) {
                pr_err("Invalid ELF header len %lu\n", info->len);
@@ -1761,6 +1763,8 @@ static int elf_validity_check(struct load_info *info)
                                       info->hdr->e_shnum);
                                goto no_exec;
                        }
+                       num_sym_secs++;
+                       sym_idx = i;
                        fallthrough;
                default:
                        err = validate_section_offset(info, shdr);
@@ -1773,6 +1777,10 @@ static int elf_validity_check(struct load_info *info)
                                   ".gnu.linkonce.this_module") == 0) {
                                num_mod_secs++;
                                mod_idx = i;
+                       } else if (strcmp(info->secstrings + shdr->sh_name,
+                                  ".modinfo") == 0) {
+                               num_info_secs++;
+                               info_idx = i;
                        }
 
                        if (shdr->sh_flags & SHF_ALLOC) {
@@ -1786,6 +1794,27 @@ static int elf_validity_check(struct load_info *info)
                }
        }
 
+       if (num_info_secs > 1) {
+               pr_err("Only one .modinfo section must exist.\n");
+               goto no_exec;
+       } else if (num_info_secs == 1) {
+               /* Try to find a name early so we can log errors with a module name */
+               info->index.info = info_idx;
+               info->name = get_modinfo(info, "name");
+       }
+
+       if (num_sym_secs != 1) {
+               pr_warn("%s: module has no symbols (stripped?)\n",
+                       info->name ?: "(missing .modinfo section or name field)");
+               goto no_exec;
+       }
+
+       /* Sets internal symbols and strings. */
+       info->index.sym = sym_idx;
+       shdr = &info->sechdrs[sym_idx];
+       info->index.str = shdr->sh_link;
+       info->strtab = (char *)info->hdr + info->sechdrs[info->index.str].sh_offset;
+
        /*
         * The ".gnu.linkonce.this_module" ELF section is special. It is
         * what modpost uses to refer to __this_module and let's use rely
@@ -1802,7 +1831,8 @@ static int elf_validity_check(struct load_info *info)
         *     size
         */
        if (num_mod_secs != 1) {
-               pr_err("Only one .gnu.linkonce.this_module section must exist.\n");
+               pr_err("module %s: Only one .gnu.linkonce.this_module section must exist.\n",
+                      info->name ?: "(missing .modinfo section or name field)");
                goto no_exec;
        }
 
@@ -1813,17 +1843,20 @@ static int elf_validity_check(struct load_info *info)
         * pedantic about it.
         */
        if (shdr->sh_type == SHT_NOBITS) {
-               pr_err(".gnu.linkonce.this_module section must have a size set\n");
+               pr_err("module %s: .gnu.linkonce.this_module section must have a size set\n",
+                      info->name ?: "(missing .modinfo section or name field)");
                goto no_exec;
        }
 
        if (!(shdr->sh_flags & SHF_ALLOC)) {
-               pr_err(".gnu.linkonce.this_module must occupy memory during process execution\n");
+               pr_err("module %s: .gnu.linkonce.this_module must occupy memory during process execution\n",
+                      info->name ?: "(missing .modinfo section or name field)");
                goto no_exec;
        }
 
        if (shdr->sh_size != sizeof(struct module)) {
-               pr_err(".gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n");
+               pr_err("module %s: .gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n",
+                      info->name ?: "(missing .modinfo section or name field)");
                goto no_exec;
        }
 
@@ -1832,6 +1865,13 @@ static int elf_validity_check(struct load_info *info)
        /* This is temporary: point mod into copy of data. */
        info->mod = (void *)info->hdr + shdr->sh_offset;
 
+       /*
+        * If we didn't load the .modinfo 'name' field earlier, fall back to
+        * on-disk struct mod 'name' field.
+        */
+       if (!info->name)
+               info->name = info->mod->name;
+
        return 0;
 
 no_exec:
@@ -1954,37 +1994,6 @@ static int rewrite_section_headers(struct load_info *info, int flags)
  */
 static int setup_load_info(struct load_info *info, int flags)
 {
-       unsigned int i;
-
-       /* 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 = get_modinfo(info, "name");
-
-       /* Find internal symbols and strings. */
-       for (i = 1; i < info->hdr->e_shnum; i++) {
-               if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
-                       info->index.sym = i;
-                       info->index.str = info->sechdrs[i].sh_link;
-                       info->strtab = (char *)info->hdr
-                               + info->sechdrs[info->index.str].sh_offset;
-                       break;
-               }
-       }
-
-       if (info->index.sym == 0) {
-               pr_warn("%s: module has no symbols (stripped?)\n",
-                       info->name ?: "(missing .modinfo section or name field)");
-               return -ENOEXEC;
-       }
-
-       /*
-        * If we didn't load the .modinfo 'name' field earlier, fall back to
-        * on-disk struct mod 'name' field.
-        */
-       if (!info->name)
-               info->name = info->mod->name;
-
        if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
                info->index.vers = 0; /* Pretend no __versions section! */
        else