* [PATCH] Module rewrite 14/20: Module License Support
@ 2002-09-25 3:05 Rusty Russell
0 siblings, 0 replies; only message in thread
From: Rusty Russell @ 2002-09-25 3:05 UTC (permalink / raw)
To: torvalds; +Cc: linux-kernel
Name: MODULE_LICENSE support for modules
Author: Rusty Russell
Status: Untested
Depends: Module/modversions.patch.gz
D: This implements EXPORT_SYMBOL_GPL and MODULE_LICENSE properly (so
D: restrictions are enforced). It also sets up a table for finding
D: the sections in the ELF object, since there are now enough
D: variables to make it sensible.
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .14496-linux-2.5.38/arch/i386/vmlinux.lds.S .14496-linux-2.5.38.updated/arch/i386/vmlinux.lds.S
--- .14496-linux-2.5.38/arch/i386/vmlinux.lds.S 2002-09-25 10:34:57.000000000 +1000
+++ .14496-linux-2.5.38.updated/arch/i386/vmlinux.lds.S 2002-09-25 10:35:23.000000000 +1000
@@ -29,6 +29,10 @@ SECTIONS
__start___ksymtab = .; /* Kernel symbol table */
__ksymtab : { *(__ksymtab) }
__stop___ksymtab = .;
+ . = ALIGN(64);
+ __start_gpl_ksymtab = .; /* Kernel symbol table (GPL only) */
+ __gpl.ksymtab : { *(__gpl.ksymtab) }
+ __stop_gpl_ksymtab = .;
.data : { /* Data */
*(.data)
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .14496-linux-2.5.38/include/linux/module.h .14496-linux-2.5.38.updated/include/linux/module.h
--- .14496-linux-2.5.38/include/linux/module.h 2002-09-25 10:35:00.000000000 +1000
+++ .14496-linux-2.5.38.updated/include/linux/module.h 2002-09-25 10:35:23.000000000 +1000
@@ -19,7 +19,6 @@
#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)
@@ -44,8 +43,36 @@ struct modversion_info {
a constant so it works in initializers. */
extern struct module __this_module;
#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 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(".license"))) = license
#else
#define THIS_MODULE ((struct module *)0)
+#define MODULE_LICENSE(license)
#endif
#ifdef CONFIG_MODULES
@@ -73,8 +100,10 @@ extern struct modversion_info modversion
NEED_MODVERSION(sym) \
EXPORT_SYMBOL_NOVERS(sym)
-/* FIXME: Enforce this. */
-#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 kernel_symbol_group
{
@@ -84,6 +113,9 @@ 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;
};
@@ -106,6 +138,9 @@ 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;
@@ -130,6 +165,9 @@ struct module
/* Am I unsafe to unload? */
int unsafe_to_unload;
+ /* My license */
+ char *license;
+
#ifdef CONFIG_MODULE_UNLOAD
/* Usage count. */
struct bigref use;
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .14496-linux-2.5.38/kernel/module.c .14496-linux-2.5.38.updated/kernel/module.c
--- .14496-linux-2.5.38/kernel/module.c 2002-09-25 10:35:01.000000000 +1000
+++ .14496-linux-2.5.38.updated/kernel/module.c 2002-09-25 10:36:50.000000000 +1000
@@ -35,10 +35,13 @@
#define DEBUGP(fmt , ...)
#endif
+/* Created by linker magic */
extern const struct exception_table_entry __start___ex_table[];
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;
@@ -49,6 +52,7 @@ static LIST_HEAD(symbols);
static struct exception_table kernel_extable;
static struct kernel_symbol_group kernel_symbols;
+static struct kernel_symbol_group kernel_gpl_symbols;
/* List of modules, protected by module_mutex */
static DECLARE_MUTEX(module_mutex);
@@ -63,13 +67,16 @@ struct sizes
/* 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;
@@ -220,6 +227,7 @@ sys_delete_module(const char *name_user,
/* Remove symbols so module count can't increase from symbol_get() */
spin_lock_irq(&modlist_lock);
list_del_init(&mod->symbols.list);
+ list_del_init(&mod->gpl_symbols.list);
spin_unlock_irq(&modlist_lock);
/* Mark it as non-live. */
@@ -240,6 +248,7 @@ sys_delete_module(const char *name_user,
try_module_get(mod); /* Can't fail */
spin_lock_irq(&modlist_lock);
list_add(&mod->symbols.list, &kernel_symbols.list);
+ list_add(&mod->gpl_symbols.list, &kernel_symbols.list);
spin_unlock_irq(&modlist_lock);
ret = -EWOULDBLOCK;
goto out;
@@ -298,7 +307,7 @@ 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);
@@ -501,6 +510,14 @@ static inline int check_version(const ch
}
#endif /* CONFIG_MODVERSIONING */
+static int module_is_gpl(struct module *mod)
+{
+ return (strcmp(mod->license, "GPL") == 0
+ || strcmp(mod->license, "GPL and additional rights") == 0
+ || strcmp(mod->license, "Dual BSD/GPL") == 0
+ || strcmp(mod->license, "Dual MPL/GPL") == 0);
+}
+
/* Find an symbol for this module (ie. resolve internals first).
It we find one, record usage. Must be holding module_mutex. */
unsigned long find_symbol_internal(Elf_Shdr *sechdrs,
@@ -519,7 +536,7 @@ 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, module_is_gpl(mod));
if (ret) {
/* This can fail due to OOM, or module unloading */
if (!use_module(mod, (*ksg)->owner))
@@ -536,6 +553,7 @@ 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);
@@ -556,7 +574,7 @@ 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 && !try_module_get(ksg->owner))
value = 0;
spin_unlock_irqrestore(&modlist_lock, flags);
@@ -792,7 +810,62 @@ static struct sizes get_sizes(const Elf_
return ret;
}
-/* Allocate and load the module */
+struct section_locate
+{
+ const char *name;
+ unsigned int *position;
+ int compulsory;
+};
+
+static int find_secs(Elf_Shdr *sechdrs,
+ const char *secstrings,
+ unsigned int numsections,
+ struct section_locate locate[],
+ unsigned int num)
+{
+ unsigned int i, j;
+
+ for (j = 0; j < num; j++)
+ *locate[j].position = 0;
+
+ for (i = 0; i < numsections; i++) {
+ const char *secname = secstrings + sechdrs[i].sh_name;
+ for (j = 0; j < num; j++) {
+ if (strcmp(locate[j].name, secname) == 0)
+ *locate[j].position = i;
+ }
+#ifndef CONFIG_MODULE_UNLOAD
+ /* Don't load .exit sections */
+ if (strstr(secname, ".exit"))
+ sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
+#endif
+ }
+ for (j = 0; j < num; j++) {
+ if (!*locate[j].position && locate[j].compulsory) {
+ printk(KERN_ERR "module has no %s\n", locate[j].name);
+ return -ENOEXEC;
+ }
+ }
+ return 0;
+}
+
+static void set_license(struct module *mod, Elf_Shdr *sechdrs, int licenseidx)
+{
+ if (licenseidx)
+ mod->license = (char *)sechdrs[licenseidx].sh_offset;
+ else
+ mod->license = "unspecified";
+
+ if (module_is_gpl(mod))
+ return;
+
+ printk(KERN_WARNING "%s: module license `%s' taints kernel.\n",
+ mod->name, mod->license);
+ tainted |= TAINT_PROPRIETORY_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)
@@ -800,14 +873,20 @@ static struct module *load_module(void *
Elf_Ehdr *hdr;
Elf_Shdr *sechdrs;
char *secstrings;
- unsigned int i, symindex, exportindex, strindex, setupindex, exindex,
- modnameindex, obsparmindex, versindex;
+ unsigned int i, symidx, exportidx, stridx, setupidx, exidx,
+ modnameidx, obsparmidx, versionidx, licenseidx, gplidx;
long arglen;
unsigned long common_length;
struct sizes sizes, used;
struct module *mod;
int err = 0;
void *ptr = NULL; /* Stops spurious gcc uninitialized warning */
+ struct section_locate loc[]
+ = { { ".symtab",&symidx,1 }, { ".modulename",&modnameidx,1 },
+ { "__ksymtab",&exportidx,0 }, {"__gpl.ksymtab",&gplidx,0 },
+ { ".setup.init",&setupidx,0 }, { "__ex_table",&exidx,0 },
+ { ".obsparm",&obsparmidx,0}, { ".license",&licenseidx,0 },
+ { ".versions",&versionidx,0}, { ".strtab",&stridx,1 } };
DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
umod, len, uargs);
@@ -837,67 +916,10 @@ static struct module *load_module(void *
sechdrs = (void *)hdr + hdr->e_shoff;
secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
- /* May not export symbols, or have setup params, so these may
- not exist */
- exportindex = setupindex = obsparmindex = versindex = 0;
-
- /* And these should exist, but gcc whinges if we don't init them */
- symindex = strindex = exindex = modnameindex = 0;
-
/* Find where important sections are */
- for (i = 1; i < hdr->e_shnum; i++) {
- if (sechdrs[i].sh_type == SHT_SYMTAB) {
- /* Internal symbols */
- DEBUGP("Symbol table in section %u\n", i);
- symindex = i;
- } else if (strcmp(secstrings+sechdrs[i].sh_name, ".modulename")
- == 0) {
- /* This module's name */
- DEBUGP("Module name in section %u\n", i);
- modnameindex = i;
- } else if (strcmp(secstrings+sechdrs[i].sh_name, "__ksymtab")
- == 0) {
- /* Exported symbols. */
- DEBUGP("EXPORT table in section %u\n", i);
- exportindex = i;
- } else if (strcmp(secstrings + sechdrs[i].sh_name, ".strtab")
- == 0) {
- /* Strings */
- DEBUGP("String table found in section %u\n", i);
- strindex = i;
- } else if (strcmp(secstrings+sechdrs[i].sh_name, ".setup.init")
- == 0) {
- /* Setup parameter info */
- DEBUGP("Setup table found in section %u\n", i);
- setupindex = i;
- } else if (strcmp(secstrings+sechdrs[i].sh_name, "__ex_table")
- == 0) {
- /* Exception table */
- DEBUGP("Exception table found in section %u\n", i);
- exindex = i;
- } else if (strcmp(secstrings+sechdrs[i].sh_name, ".obsparm")
- == 0) {
- /* Obsolete MODULE_PARM() table */
- DEBUGP("Obsolete param found in section %u\n", i);
- obsparmindex = i;
- } else if (strcmp(secstrings+sechdrs[i].sh_name, ".versions")
- == 0) {
- /* Module versioning table. */
- DEBUGP("Symbol versions found in section %u\n", i);
- versindex = i;
- }
-#ifndef CONFIG_MODULE_UNLOAD
- /* Don't load .exit sections */
- if (strstr(secstrings+sechdrs[i].sh_name, ".exit"))
- sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
-#endif
- }
-
- if (!modnameindex) {
- DEBUGP("Module has no name!\n");
- err = -ENOEXEC;
+ err = find_secs(sechdrs, secstrings, hdr->e_shnum,loc,ARRAY_SIZE(loc));
+ if (err < 0)
goto free_hdr;
- }
/* Now allocate space for the module proper, and copy name and args. */
err = strlen_user(uargs);
@@ -915,7 +937,7 @@ static struct module *load_module(void *
err = -EFAULT;
goto free_mod;
}
- strncpy(mod->name, (char *)hdr + sechdrs[modnameindex].sh_offset,
+ strncpy(mod->name, (char *)hdr + sechdrs[modnameidx].sh_offset,
sizeof(mod->name)-1);
if (find_module(mod->name)) {
@@ -927,12 +949,14 @@ static struct module *load_module(void *
INIT_LIST_HEAD(&mod->extable.list);
INIT_LIST_HEAD(&mod->list);
INIT_LIST_HEAD(&mod->symbols.list);
- mod->symbols.owner = mod;
+ INIT_LIST_HEAD(&mod->gpl_symbols.list);
+ mod->symbols.owner = mod->gpl_symbols.owner = mod;
+ mod->gpl_symbols.gplonly = 1;
module_unload_init(mod);
/* How much space will we need? (Common area in core) */
sizes = get_sizes(hdr, sechdrs, secstrings);
- common_length = read_commons(hdr, &sechdrs[symindex]);
+ common_length = read_commons(hdr, &sechdrs[symidx]);
sizes.core_size += common_length;
/* Set these up: arch's can add to them */
@@ -943,7 +967,6 @@ static struct module *load_module(void *
ptr = module_core_alloc(hdr, sechdrs, secstrings, mod);
if (IS_ERR(ptr))
goto free_mod;
-
mod->module_core = ptr;
ptr = module_init_alloc(hdr, sechdrs, secstrings, mod);
@@ -970,40 +993,40 @@ static struct module *load_module(void *
if (used.init_size > mod->init_size || used.core_size > mod->core_size)
BUG();
+ /* Set up license info based on contents of section */
+ set_license(mod, sechdrs, licenseidx);
+
/* Fix up syms, so that st_value is a pointer to location. */
- err = simplify_symbols(sechdrs, symindex, strindex, versindex,
+ err = simplify_symbols(sechdrs, symidx, stridx, versionidx,
mod->module_core, mod);
if (err < 0)
goto cleanup;
/* Always do SMP check for modversions. */
err = check_version(mod->name, "__SMP__",
- (void *)sechdrs[versindex].sh_offset,
- sechdrs[versindex].sh_size
+ (void *)sechdrs[versionidx].sh_offset,
+ sechdrs[versionidx].sh_size
/ sizeof(struct modversion_info));
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_offset;
- }
+ /* Set up EXPORTed & EXPORT_GPLed symbols */
+ mod->symbols.num_syms = (sechdrs[exportidx].sh_size
+ / sizeof(*mod->symbols.syms));
+ mod->symbols.syms = (void *)sechdrs[exportidx].sh_offset;
+ mod->gpl_symbols.num_syms = (sechdrs[gplidx].sh_size
+ / sizeof(*mod->gpl_symbols.syms));
+ mod->gpl_symbols.syms = (void *)sechdrs[gplidx].sh_offset;
- /* Set up exception table */
- if (exindex) {
- /* FIXME: Sort exception table. */
- mod->extable.num_entries = (sechdrs[exindex].sh_size
- / sizeof(struct
- exception_table_entry));
- mod->extable.entry = (void *)sechdrs[exindex].sh_offset;
- }
+ /* Set up exception table. FIXME: Sort exception table. */
+ mod->extable.num_entries = (sechdrs[exidx].sh_size
+ / sizeof(struct exception_table_entry));
+ mod->extable.entry = (void *)sechdrs[exidx].sh_offset;
/* Now handle each section. */
for (i = 1; i < hdr->e_shnum; i++) {
err = handle_section(secstrings + sechdrs[i].sh_name,
- sechdrs, strindex, symindex, i, mod);
+ sechdrs, stridx, symidx, i, mod);
if (err < 0)
goto cleanup;
}
@@ -1012,7 +1035,7 @@ static struct module *load_module(void *
put a dummy function in, because otherwise this can be a
very confusing silent failure */
if (!mod->init) {
- printk("%s: No init function.\n", mod->name);
+ printk(KERN_ERR "%s: No init function.\n", mod->name);
err = -ENOEXEC;
goto cleanup;
}
@@ -1021,20 +1044,20 @@ static struct module *load_module(void *
if (err < 0)
goto cleanup;
- if (obsparmindex) {
+ if (obsparmidx) {
err = obsolete_params(mod->name, mod->args,
(struct obsolete_modparm *)
- sechdrs[obsparmindex].sh_offset,
- sechdrs[obsparmindex].sh_size
+ sechdrs[obsparmidx].sh_offset,
+ sechdrs[obsparmidx].sh_size
/ sizeof(struct obsolete_modparm),
- sechdrs, symindex,
- (char *)sechdrs[strindex].sh_offset);
+ sechdrs, symidx,
+ (char *)sechdrs[stridx].sh_offset);
} else {
/* Size of section 0 is 0, so this works well if no params */
err = parse_args(mod->name, mod->args,
(struct kernel_param *)
- sechdrs[setupindex].sh_offset,
- sechdrs[setupindex].sh_size
+ sechdrs[setupidx].sh_offset,
+ sechdrs[setupidx].sh_size
/ sizeof(struct kernel_param),
NULL);
}
@@ -1115,6 +1138,7 @@ sys_init_module(void *umod,
/* Now it's a first class citizen! */
spin_lock_irq(&modlist_lock);
list_add(&mod->symbols.list, &kernel_symbols.list);
+ list_add(&mod->gpl_symbols.list, &kernel_symbols.list);
spin_unlock_irq(&modlist_lock);
list_add(&mod->list, &modules);
@@ -1179,7 +1203,12 @@ static int __init 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);
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
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