[PATCH] MODULE_LICENSE and EXPORT_SYMBOL_GPL support

From: Rusty Russell (rusty@rustcorp.com.au)
Date: Sun Jan 05 2003 - 19:04:16 EST


Re-xmit: Linus, please apply.

Now simply a flag, and the license text itself is in a .init section,
so will be discarded for most archs.

Rusty.

--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.

Name: MODULE_LICENSE support for modules Author: Rusty Russell Status: Tested in 2.5.54

D: This implements EXPORT_SYMBOL_GPL and MODULE_LICENSE properly (so D: restrictions are enforced). Also fixes "proprietory" spelling.

diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5-bk/include/linux/kernel.h working-2.5-bk-module-license/include/linux/kernel.h --- linux-2.5-bk/include/linux/kernel.h Thu Jan 2 14:48:00 2003 +++ working-2.5-bk-module-license/include/linux/kernel.h Fri Jan 3 16:32:18 2003 @@ -105,7 +105,7 @@ extern int oops_in_progress; /* If set, extern int tainted; extern const char *print_tainted(void); -#define TAINT_PROPRIETORY_MODULE (1<<0) +#define TAINT_PROPRIETARY_MODULE (1<<0) #define TAINT_FORCED_MODULE (1<<1) #define TAINT_UNSAFE_SMP (1<<2) #define TAINT_FORCED_RMMOD (1<<3) diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5-bk/include/linux/module.h working-2.5-bk-module-license/include/linux/module.h --- linux-2.5-bk/include/linux/module.h Thu Jan 2 14:48:00 2003 +++ working-2.5-bk-module-license/include/linux/module.h Fri Jan 3 17:12:33 2003 @@ -21,7 +21,6 @@ #include <asm/uaccess.h> /* For struct exception_table_entry */ /* Not Yet Implemented */ -#define MODULE_LICENSE(name) #define MODULE_AUTHOR(name) #define MODULE_DESCRIPTION(desc) #define MODULE_SUPPORTED_DEVICE(name) @@ -57,11 +56,41 @@ extern const struct gtype##_id __mod_##g #define THIS_MODULE (&__this_module) +/* + * The following license idents are currently accepted as indicating free + * software modules + * + * "GPL" [GNU Public License v2 or later] + * "GPL v2" [GNU Public License v2] + * "GPL and additional rights" [GNU Public License v2 rights and more] + * "Dual BSD/GPL" [GNU Public License v2 + * or BSD license choice] + * "Dual MPL/GPL" [GNU Public License v2 + * or Mozilla license choice] + * + * The following other idents are available + * + * "Proprietary" [Non free products] + * + * There are dual licensed components, but when running with Linux it is the + * GPL that is relevant so this is a non issue. Similarly LGPL linked with GPL + * is a GPL combined work. + * + * This exists for several reasons + * 1. So modinfo can show license info for users wanting to vet their setup + * is free + * 2. So the community can ignore bug reports including proprietary modules + * 3. So vendors can do likewise based on their own policies + */ +#define MODULE_LICENSE(license) \ + static const char __module_license[] \ + __attribute__((section(".init.license"))) = license + #else /* !MODULE */ #define MODULE_GENERIC_TABLE(gtype,name) #define THIS_MODULE ((struct module *)0) - +#define MODULE_LICENSE(license) #endif #define MODULE_DEVICE_TABLE(type,name) \ @@ -75,6 +104,9 @@ struct kernel_symbol_group /* Module which owns it (if any) */ struct module *owner; + /* Are we internal use only? */ + int gplonly; + unsigned int num_syms; const struct kernel_symbol *syms; }; @@ -101,7 +133,11 @@ void *__symbol_get_gpl(const char *symbo = { (unsigned long)&sym, MODULE_SYMBOL_PREFIX #sym } #define EXPORT_SYMBOL_NOVERS(sym) EXPORT_SYMBOL(sym) -#define EXPORT_SYMBOL_GPL(sym) EXPORT_SYMBOL(sym) + +#define EXPORT_SYMBOL_GPL(sym) \ + const struct kernel_symbol __ksymtab_##sym \ + __attribute__((section("__gpl_ksymtab"))) \ + = { (unsigned long)&sym, #sym } struct module_ref { @@ -128,6 +164,9 @@ struct module /* Exported symbols */ struct kernel_symbol_group symbols; + /* GPL-only exported symbols. */ + struct kernel_symbol_group gpl_symbols; + /* Exception tables */ struct exception_table extable; @@ -149,6 +188,9 @@ struct module /* Am I unsafe to unload? */ int unsafe; + /* Am I GPL-compatible */ + int license_gplok; + #ifdef CONFIG_MODULE_UNLOAD /* Reference counts */ struct module_ref ref[NR_CPUS]; @@ -293,6 +335,7 @@ struct module __this_module __attribute__((section(".gnu.linkonce.this_module"))) = { .name = __stringify(KBUILD_MODNAME), .symbols = { .owner = &__this_module }, + .gpl_symbols = { .owner = &__this_module, .gplonly = 1 }, .init = init_module, #ifdef CONFIG_MODULE_UNLOAD .exit = cleanup_module, diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5-bk/kernel/extable.c working-2.5-bk-module-license/kernel/extable.c --- linux-2.5-bk/kernel/extable.c Thu Jan 2 12:36:08 2003 +++ working-2.5-bk-module-license/kernel/extable.c Fri Jan 3 16:29:26 2003 @@ -24,6 +24,8 @@ extern const struct exception_table_entr extern const struct exception_table_entry __stop___ex_table[]; extern const struct kernel_symbol __start___ksymtab[]; extern const struct kernel_symbol __stop___ksymtab[]; +extern const struct kernel_symbol __start___gpl_ksymtab[]; +extern const struct kernel_symbol __stop___gpl_ksymtab[]; /* Protects extables and symbol tables */ spinlock_t modlist_lock = SPIN_LOCK_UNLOCKED; @@ -34,13 +36,20 @@ LIST_HEAD(symbols); static struct exception_table kernel_extable; static struct kernel_symbol_group kernel_symbols; +static struct kernel_symbol_group kernel_gpl_symbols; void __init extable_init(void) { /* Add kernel symbols to symbol table */ kernel_symbols.num_syms = (__stop___ksymtab - __start___ksymtab); kernel_symbols.syms = __start___ksymtab; + kernel_symbols.gplonly = 0; list_add(&kernel_symbols.list, &symbols); + kernel_gpl_symbols.num_syms = (__stop___gpl_ksymtab + - __start___gpl_ksymtab); + kernel_gpl_symbols.syms = __start___gpl_ksymtab; + kernel_gpl_symbols.gplonly = 1; + list_add(&kernel_gpl_symbols.list, &symbols); /* Add kernel exception table to exception tables */ kernel_extable.num_entries = (__stop___ex_table -__start___ex_table); diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5-bk/kernel/module.c working-2.5-bk-module-license/kernel/module.c --- linux-2.5-bk/kernel/module.c Thu Jan 2 14:48:01 2003 +++ working-2.5-bk-module-license/kernel/module.c Fri Jan 3 16:47:20 2003 @@ -72,13 +72,16 @@ EXPORT_SYMBOL(init_module); /* Find a symbol, return value and the symbol group */ static unsigned long __find_symbol(const char *name, - struct kernel_symbol_group **group) + struct kernel_symbol_group **group, + int gplok) { struct kernel_symbol_group *ks; list_for_each_entry(ks, &symbols, list) { unsigned int i; + if (ks->gplonly && !gplok) + continue; for (i = 0; i < ks->num_syms; i++) { if (strcmp(ks->syms[i].name, name) == 0) { *group = ks; @@ -502,7 +505,7 @@ void __symbol_put(const char *symbol) unsigned long flags; spin_lock_irqsave(&modlist_lock, flags); - if (!__find_symbol(symbol, &ksg)) + if (!__find_symbol(symbol, &ksg, 1)) BUG(); module_put(ksg->owner); spin_unlock_irqrestore(&modlist_lock, flags); @@ -721,7 +724,7 @@ unsigned long find_symbol_internal(Elf_S } /* Look in other modules... */ spin_lock_irq(&modlist_lock); - ret = __find_symbol(name, ksg); + ret = __find_symbol(name, ksg, mod->license_gplok); if (ret) { /* This can fail due to OOM, or module unloading */ if (!use_module(mod, (*ksg)->owner)) @@ -738,6 +741,7 @@ static void free_module(struct module *m list_del(&mod->list); spin_lock_irq(&modlist_lock); list_del(&mod->symbols.list); + list_del(&mod->gpl_symbols.list); list_del(&mod->extable.list); spin_unlock_irq(&modlist_lock); @@ -758,7 +762,7 @@ void *__symbol_get(const char *symbol) unsigned long value, flags; spin_lock_irqsave(&modlist_lock, flags); - value = __find_symbol(symbol, &ksg); + value = __find_symbol(symbol, &ksg, 1); if (value && !strong_try_module_get(ksg->owner)) value = 0; spin_unlock_irqrestore(&modlist_lock, flags); @@ -930,7 +934,34 @@ static void layout_sections(struct modul } } -/* Allocate and load the module */ +static inline int license_is_gpl_compatible(const char *license) +{ + return (strcmp(license, "GPL") == 0 + || strcmp(license, "GPL v2") == 0 + || strcmp(license, "GPL and additional rights") == 0 + || strcmp(license, "Dual BSD/GPL") == 0 + || strcmp(license, "Dual MPL/GPL") == 0); +} + +static void set_license(struct module *mod, Elf_Shdr *sechdrs, int licenseidx) +{ + char *license; + + if (licenseidx) + license = (char *)sechdrs[licenseidx].sh_addr; + else + license = "unspecified"; + + mod->license_gplok = license_is_gpl_compatible(license); + if (!mod->license_gplok) { + printk(KERN_WARNING "%s: module license '%s' taints kernel.\n", + mod->name, license); + tainted |= TAINT_PROPRIETARY_MODULE; + } +} + +/* Allocate and load the module: note that size of section 0 is always + zero, and we rely on this for optional sections. */ static struct module *load_module(void *umod, unsigned long len, const char *uargs) @@ -939,7 +970,7 @@ static struct module *load_module(void * Elf_Shdr *sechdrs; char *secstrings, *args; unsigned int i, symindex, exportindex, strindex, setupindex, exindex, - modindex, obsparmindex; + modindex, obsparmindex, licenseindex, gplindex; long arglen; struct module *mod; long err = 0; @@ -975,7 +1006,7 @@ static struct module *load_module(void * /* May not export symbols, or have setup params, so these may not exist */ - exportindex = setupindex = obsparmindex = 0; + exportindex = setupindex = obsparmindex = gplindex = licenseindex = 0; /* And these should exist, but gcc whinges if we don't init them */ symindex = strindex = exindex = modindex = 0; @@ -1018,6 +1049,16 @@ static struct module *load_module(void * /* Obsolete MODULE_PARM() table */ DEBUGP("Obsolete param found in section %u\n", i); obsparmindex = i; + } else if (strcmp(secstrings+sechdrs[i].sh_name,".init.license") + == 0) { + /* MODULE_LICENSE() */ + DEBUGP("Licence found in section %u\n", i); + licenseindex = i; + } else if (strcmp(secstrings+sechdrs[i].sh_name, + "__gpl_ksymtab") == 0) { + /* EXPORT_SYMBOL_GPL() */ + DEBUGP("GPL symbols found in section %u\n", i); + gplindex = i; } #ifdef CONFIG_KALLSYMS /* symbol and string tables for decoding later. */ @@ -1113,17 +1154,21 @@ static struct module *load_module(void * /* Now we've moved module, initialize linked lists, etc. */ module_unload_init(mod); + /* Set up license info based on contents of section */ + set_license(mod, sechdrs, licenseindex); + /* Fix up syms, so that st_value is a pointer to location. */ err = simplify_symbols(sechdrs, symindex, strindex, mod); if (err < 0) goto cleanup; - /* Set up EXPORTed symbols */ - if (exportindex) { - mod->symbols.num_syms = (sechdrs[exportindex].sh_size - / sizeof(*mod->symbols.syms)); - mod->symbols.syms = (void *)sechdrs[exportindex].sh_addr; - } + /* Set up EXPORTed & EXPORT_GPLed symbols (section 0 is 0 length) */ + mod->symbols.num_syms = (sechdrs[exportindex].sh_size + / sizeof(*mod->symbols.syms)); + mod->symbols.syms = (void *)sechdrs[exportindex].sh_addr; + mod->gpl_symbols.num_syms = (sechdrs[gplindex].sh_size + / sizeof(*mod->symbols.syms)); + mod->gpl_symbols.syms = (void *)sechdrs[gplindex].sh_addr; /* Set up exception table */ if (exindex) { @@ -1228,6 +1273,7 @@ sys_init_module(void *umod, spin_lock_irq(&modlist_lock); list_add(&mod->extable.list, &extables); list_add_tail(&mod->symbols.list, &symbols); + list_add_tail(&mod->gpl_symbols.list, &symbols); spin_unlock_irq(&modlist_lock); list_add(&mod->list, &modules); diff -urNp --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5-bk/kernel/panic.c working-2.5-bk-module-license/kernel/panic.c --- linux-2.5-bk/kernel/panic.c Thu Jan 2 12:25:16 2003 +++ working-2.5-bk-module-license/kernel/panic.c Fri Jan 3 16:32:55 2003 @@ -103,7 +103,7 @@ NORET_TYPE void panic(const char * fmt, /** * print_tainted - return a string to represent the kernel taint state. * - * 'P' - Proprietory module has been loaded. + * 'P' - Proprietary module has been loaded. * 'F' - Module has been forcibly loaded. * 'S' - SMP with CPUs not designed for SMP. * @@ -115,7 +115,7 @@ const char *print_tainted() static char buf[20]; if (tainted) { snprintf(buf, sizeof(buf), "Tainted: %c%c%c", - tainted & TAINT_PROPRIETORY_MODULE ? 'P' : 'G', + tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G', tainted & TAINT_FORCED_MODULE ? 'F' : ' ', tainted & TAINT_UNSAFE_SMP ? 'S' : ' '); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/



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