livepatch: Prevent module-specific KLP rela sections from referencing vmlinux symbols

}

static int klp_resolve_symbols(Elf64_Shdr *sechdrs, const char *strtab,

			       unsigned int symndx, Elf_Shdr *relasec)

			       unsigned int symndx, Elf_Shdr *relasec,

			       const char *sec_objname)

{

	int i, cnt, vmlinux, ret;

	char objname[MODULE_NAME_LEN];

	char symname[KSYM_NAME_LEN];

	int i, cnt, ret;

	char sym_objname[MODULE_NAME_LEN];

	char sym_name[KSYM_NAME_LEN];

	Elf_Rela *relas;

	Elf_Sym *sym;

	unsigned long sympos, addr;

	bool sym_vmlinux;

	bool sec_vmlinux = !strcmp(sec_objname, "vmlinux");

	/*

	 * Since the field widths for objname and symname in the sscanf()

	 * Since the field widths for sym_objname and sym_name in the sscanf()

	 * call are hard-coded and correspond to MODULE_NAME_LEN and

	 * KSYM_NAME_LEN respectively, we must make sure that MODULE_NAME_LEN

	 * and KSYM_NAME_LEN have the values we expect them to have.

			return -EINVAL;

		}

		/* Format: .klp.sym.objname.symname,sympos */

		/* Format: .klp.sym.sym_objname.sym_name,sympos */

		cnt = sscanf(strtab + sym->st_name,

			     ".klp.sym.%55[^.].%127[^,],%lu",

			     objname, symname, &sympos);

			     sym_objname, sym_name, &sympos);

		if (cnt != 3) {

			pr_err("symbol %s has an incorrectly formatted name\n",

			       strtab + sym->st_name);

			return -EINVAL;

		}

		sym_vmlinux = !strcmp(sym_objname, "vmlinux");

		/*

		 * Prevent module-specific KLP rela sections from referencing

		 * vmlinux symbols.  This helps prevent ordering issues with

		 * module special section initializations.  Presumably such

		 * symbols are exported and normal relas can be used instead.

		 */

		if (!sec_vmlinux && sym_vmlinux) {

			pr_err("invalid access to vmlinux symbol '%s' from module-specific livepatch relocation section",

			       sym_name);

			return -EINVAL;

		}

		/* klp_find_object_symbol() treats a NULL objname as vmlinux */

		vmlinux = !strcmp(objname, "vmlinux");

		ret = klp_find_object_symbol(vmlinux ? NULL : objname,

					     symname, sympos, &addr);

		ret = klp_find_object_symbol(sym_vmlinux ? NULL : sym_objname,

					     sym_name, sympos, &addr);

		if (ret)

			return ret;

	if (strcmp(objname ? objname : "vmlinux", sec_objname))

		return 0;

	ret = klp_resolve_symbols(sechdrs, strtab, symndx, sec);

	ret = klp_resolve_symbols(sechdrs, strtab, symndx, sec, sec_objname);

	if (ret)

		return ret;