From 8c9ce89c5b63028dd3be43807f10b009cd2c6e51 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 30 May 2022 18:01:38 +0900 Subject: [PATCH] modpost: simplify mod->name allocation mod->name is set to the ELF filename with the suffix ".o" stripped. The current code calls strdup() and free() to manipulate the string, but a simpler approach is to pass new_module() with the name length subtracted by 2. Also, check if the passed filename ends with ".o" before stripping it. The current code blindly chops the suffix: tmp[strlen(tmp) - 2] = '\0' It will cause buffer under-run if strlen(tmp) < 2; Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 9269735f85c5..c1558bacf717 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -172,11 +172,11 @@ static struct module *find_module(const char *modname) return NULL; } -static struct module *new_module(const char *modname) +static struct module *new_module(const char *name, size_t namelen) { struct module *mod; - mod = NOFAIL(malloc(sizeof(*mod) + strlen(modname) + 1)); + mod = NOFAIL(malloc(sizeof(*mod) + namelen + 1)); memset(mod, 0, sizeof(*mod)); INIT_LIST_HEAD(&mod->exported_symbols); @@ -184,8 +184,9 @@ static struct module *new_module(const char *modname) INIT_LIST_HEAD(&mod->missing_namespaces); INIT_LIST_HEAD(&mod->imported_namespaces); - strcpy(mod->name, modname); - mod->is_vmlinux = (strcmp(modname, "vmlinux") == 0); + memcpy(mod->name, name, namelen); + mod->name[namelen] = '\0'; + mod->is_vmlinux = (strcmp(mod->name, "vmlinux") == 0); /* * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE() @@ -2017,16 +2018,14 @@ static void read_symbols(const char *modname) if (!parse_elf(&info, modname)) return; - { - char *tmp; - - /* strip trailing .o */ - tmp = NOFAIL(strdup(modname)); - tmp[strlen(tmp) - 2] = '\0'; - mod = new_module(tmp); - free(tmp); + if (!strends(modname, ".o")) { + error("%s: filename must be suffixed with .o\n", modname); + return; } + /* strip trailing .o */ + mod = new_module(modname, strlen(modname) - strlen(".o")); + if (!mod->is_vmlinux) { license = get_modinfo(&info, "license"); if (!license) @@ -2488,7 +2487,7 @@ static void read_dump(const char *fname) mod = find_module(modname); if (!mod) { - mod = new_module(modname); + mod = new_module(modname, strlen(modname)); mod->from_dump = true; } s = sym_add_exported(symname, mod, gpl_only);