Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 24 Sep 2002 23:23:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 24 Sep 2002 23:23:10 -0400 Received: from dp.samba.org ([66.70.73.150]:44160 "EHLO lists.samba.org") by vger.kernel.org with ESMTP id ; Tue, 24 Sep 2002 23:16:47 -0400 From: Rusty Russell To: torvalds@transmeta.com Cc: linux-kernel@vger.kernel.org, Kai Germaschewski Subject: [PATCH] Module rewrite 13/20: Module versions Date: Wed, 25 Sep 2002 13:03:04 +1000 Message-Id: <20020925032201.9CAD52C120@lists.samba.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 17893 Lines: 478 [ This does not delete the old CONFIG_MODVERSIONS code: I'll leave that to Kai's pleasure, in return for fixing remaining makefile issues. You'll note that the export-objs lines in Makefiles should no longer be neccessary now. ] Name: modversions support Author: Rusty Russell Status: Tested on 2.5.38 Depends: Module/param-oldstyle.patch.gz Depends: Misc/2-5-38-fixes.patch.gz D: This implementes CONFIG_MODVERSIONING (similar to the old D: CONFIG_MODVERSIONS, but with a separate name for the moment so the D: two can be clearly separated). D: D: The makefiles do not quite work correctly: you have to build using: D: make kernel/modversions.o bzImage D: make modules D: D: The idea is that modules which want to export symbols place their D: full path name in the .needmodversion section. Just before the kernel D: is linked, these names are extracted, and genksyms scans those files to D: create a version table. This table is then linked into the kernel. D: D: For modules, after they have been built, another pass adds a D: .versions section to each module containing the version of each D: undefined symbol in it. D: D: These symbol versions are then checked on insmod. This means that D: you can insert an unversioned module into a versioned kernel, and D: vice versa (which taints your kernel). D: D: Also, the offensive export-objs defines in Makefiles are now unneccessary. diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .3225-linux-2.5.38/Makefile .3225-linux-2.5.38.updated/Makefile --- .3225-linux-2.5.38/Makefile 2002-09-25 07:34:07.000000000 +1000 +++ .3225-linux-2.5.38.updated/Makefile 2002-09-25 07:34:34.000000000 +1000 @@ -296,6 +296,7 @@ cmd_link_vmlinux = $(LD) $(LDFLAGS) $(LD $(LIBS) \ $(DRIVERS) \ $(NETWORKS) \ + $(kernel_modversions) \ --end-group \ -o vmlinux @@ -314,7 +315,7 @@ endef LDFLAGS_vmlinux += -T arch/$(ARCH)/vmlinux.lds.s -vmlinux: $(vmlinux-objs) arch/$(ARCH)/vmlinux.lds.s FORCE +vmlinux: $(vmlinux-objs) $(kernel_modversions) arch/$(ARCH)/vmlinux.lds.s FORCE $(call if_changed_rule,link_vmlinux) # The actual objects are generated when descending, @@ -424,8 +425,30 @@ depend dep: .hdepend @$(MAKE) include/linux/modversions.h @touch $@ -ifdef CONFIG_MODVERSIONS +ifdef CONFIG_MODVERSIONING +# Module versions for the kernel: +kernel_modversions = kernel/modversions.o +quiet_cmd_get_modversions = MODVER $@ +cmd_get_modversions = $(CONFIG_SHELL) scripts/extract_versions $(VERSION).$(PATCHLEVEL).$(SUBLEVEL) $(vmlinux-objs) >$@ + +include/linux/generated-modversions.h: $(vmlinux-objs) scripts/extract_versions + $(call cmd,get_modversions) + +kernel/modversions.o: kernel/modversions.c include/linux/generated-modversions.h + $(CC) $(CFLAGS) -c -o $@ $< + +# FIXME: We don't version symbols exported by modules --RR +module_modversions = add_modversions + +add_modversions: include/linux/generated-modversions.h $(patsubst %, _addmodver_%, $(SUBDIRS)) + +$(patsubst %,_addmodver_%,$(SUBDIRS)): FORCE + @$(MAKE) -C $(patsubst _addmodver_%, %, $@) add_modversions + +endif + +ifdef CONFIG_MODVERSIONS # Update modversions.h, but only if it would change. include/linux/modversions.h: scripts/fixdep prepare FORCE @@ -465,7 +488,7 @@ MODFLAGS += -include $(objtree)/include/ endif .PHONY: modules -modules: $(SUBDIRS) +modules: $(SUBDIRS) $(module_modversions) # Install modules diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .3225-linux-2.5.38/Rules.make .3225-linux-2.5.38.updated/Rules.make --- .3225-linux-2.5.38/Rules.make 2002-09-25 07:34:07.000000000 +1000 +++ .3225-linux-2.5.38.updated/Rules.make 2002-09-25 07:34:34.000000000 +1000 @@ -44,6 +44,13 @@ endif obj := . src := . +# We insert an extra symbol for modversions on SMP +ifdef CONFIG_SMP +modversions_extra = { "__SMP__", 0x01 }, +else +modversions_extra = { "__SMP__", 0x00 }, +endif + # For use in the quiet output echo_target = $(RELDIR)/$@ @@ -130,7 +137,7 @@ basename_flags = -DKBUILD_BASENAME=$(sub modname_flags = -DKBUILD_MODNAME=$(subst $(comma),_,$(subst -,_,$(modname))) c_flags = -Wp,-MD,$(depfile) $(CFLAGS) $(NOSTDINC_FLAGS) \ $(modkern_cflags) $(EXTRA_CFLAGS) $(CFLAGS_$(*F).o) \ - $(basename_flags) $(modname_flags) $(export_flags) + $(basename_flags) $(modname_flags) $(export_flags) -D__DIRNAME__=\"$(CURDIR)\" # Finds the multi-part object the current object will be linked into modname-multi = $(subst $(space),_,$(strip $(foreach m,$(multi-used),\ @@ -271,6 +278,12 @@ first_rule: $(if $(KBUILD_BUILTIN),$(O_T sub_dirs @echo -n +# Module versioning +add_modversions: sub_dirs FORCE + @RELDIR=$(RELDIR) $(CONFIG_SHELL) -e $(TOPDIR)/scripts/add_versions '$(modversions_extra)' $(obj-m) + + + # Compile C sources (.c) # --------------------------------------------------------------------------- diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .3225-linux-2.5.38/include/linux/module.h .3225-linux-2.5.38.updated/include/linux/module.h --- .3225-linux-2.5.38/include/linux/module.h 2002-09-25 07:34:11.000000000 +1000 +++ .3225-linux-2.5.38.updated/include/linux/module.h 2002-09-25 07:34:51.000000000 +1000 @@ -34,6 +34,11 @@ struct kernel_symbol char name[MODULE_NAME_LEN]; }; +struct modversion_info { + char symbol[MODULE_NAME_LEN]; + unsigned long checksum; +}; + #ifdef MODULE /* This is magically filled in by the linker, but THIS_MODULE must be a constant so it works in initializers. */ @@ -47,13 +52,28 @@ extern struct module __this_module; /* Get/put a kernel symbol (calls should be symmetric) */ #define symbol_get(x) ((typeof(&x))(__get_symbol(#x))) +#ifdef CONFIG_MODVERSIONING +#define NEED_MODVERSION(sym) \ + const char __needver_##sym[256] \ + __attribute__((section(".needmodversion"))) \ + = { __DIRNAME__ "/" __FILE__ }; + +extern struct modversion_info modversions[]; +#else /* !CONFIG_MODVERSIONING */ +#define NEED_MODVERSION(sym) +#endif + /* For every exported symbol, place a struct in the __ksymtab section */ -#define EXPORT_SYMBOL(sym) \ +#define EXPORT_SYMBOL_NOVERS(sym) \ const struct kernel_symbol __ksymtab_##sym \ __attribute__((section("__ksymtab"))) \ = { (unsigned long)&sym, #sym } -#define EXPORT_SYMBOL_NOVERS(sym) EXPORT_SYMBOL(sym) +#define EXPORT_SYMBOL(sym) \ + NEED_MODVERSION(sym) \ + EXPORT_SYMBOL_NOVERS(sym) + +/* FIXME: Enforce this. */ #define EXPORT_SYMBOL_GPL(sym) EXPORT_SYMBOL(sym) struct kernel_symbol_group @@ -285,4 +305,12 @@ extern int module_dummy_usage; (((m)->module_init \ && __mod_between((p),(n),(m)->module_init,(m)->init_size)) \ || __mod_between((p),(n),(m)->module_core,(m)->core_size)) + +#ifdef __GENKSYMS__ +/* We want the EXPORT_SYMBOL tag left intact for recognition. */ +#undef EXPORT_SYMBOL +#undef EXPORT_SYMBOL_NOVERS +#undef EXPORT_SYMBOL_GPL +#endif /* __GENKSYMS__ */ + #endif /* _LINUX_MODULE_H */ diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .3225-linux-2.5.38/init/Config.in .3225-linux-2.5.38.updated/init/Config.in --- .3225-linux-2.5.38/init/Config.in 2002-09-25 07:34:11.000000000 +1000 +++ .3225-linux-2.5.38.updated/init/Config.in 2002-09-25 07:34:34.000000000 +1000 @@ -15,6 +15,7 @@ mainmenu_option next_comment comment 'Loadable module support' bool 'Enable loadable module support' CONFIG_MODULES dep_bool ' Kernel module loader' CONFIG_KMOD $CONFIG_MODULES +dep_bool ' Kernel module versioning' CONFIG_MODVERSIONING $CONFIG_MODULES dep_bool ' Module unloading' CONFIG_MODULE_UNLOAD $CONFIG_MODULES dep_bool ' Obsolete module parameters' CONFIG_OBSOLETE_MODPARM $CONFIG_MODULES endmenu diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .3225-linux-2.5.38/kernel/module.c .3225-linux-2.5.38.updated/kernel/module.c --- .3225-linux-2.5.38/kernel/module.c 2002-09-25 07:34:11.000000000 +1000 +++ .3225-linux-2.5.38.updated/kernel/module.c 2002-09-25 07:34:34.000000000 +1000 @@ -459,6 +459,48 @@ static int obsolete_params(const char *n } #endif /* CONFIG_OBSOLETE_MODPARM */ +#ifdef CONFIG_MODVERSIONING +static inline int check_version(const char *name, + const char *symname, + const struct modversion_info *versions, + unsigned int num) +{ + unsigned int i, k; + + /* First search kernel (unversioned symbols not listed). */ + for (k = 0; !streq(modversions[k].symbol, symname); k++) + if (!modversions[k].symbol[0]) + return 0; + + /* Now see if module has matching symbol. */ + for (i = 0; i < num; i++) { + if (streq(versions[i].symbol, symname)) { + if (versions[i].checksum == modversions[k].checksum) + return 0; + printk("%s: disagrees about version of symbol %s\n", + name, symname); + DEBUGP("Kernel checksum %lX vs module %lX\n", + modversions[k].checksum, versions[i].checksum); + return -ESRCH; + } + } + + /* Not in module's version table. OK, but that taints the kernel. */ + printk("%s: no version for %s found: kernel tainted.\n", + name, symname); + tainted |= TAINT_FORCED_MODULE; + return 0; +} +#else +static inline int check_version(const char *name, + const char *symname, + const struct modversion_info *versions, + unsigned int num) +{ + return 0; +} +#endif /* CONFIG_MODVERSIONING */ + /* 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, @@ -644,21 +686,21 @@ static unsigned long read_commons(void * } /* Change all symbols so that sh_value encodes the pointer directly. */ -static void simplify_symbols(Elf_Shdr *sechdrs, +static int simplify_symbols(Elf_Shdr *sechdrs, unsigned int symindex, unsigned int strindex, + unsigned int versindex, void *common, struct module *mod) { + int ret; unsigned int i; - Elf_Sym *sym; + Elf_Sym *sym = (void *)sechdrs[symindex].sh_offset; /* First simplify defined symbols, so if they become the "answer" to undefined symbols, copying their st_value us correct. */ - for (sym = (void *)sechdrs[symindex].sh_offset, i = 0; - i < sechdrs[symindex].sh_size / sizeof(Elf_Sym); - i++) { + for (i = 0; i < sechdrs[symindex].sh_size / sizeof(Elf_Sym); i++) { switch (sym[i].st_shndx) { case SHN_COMMON: /* Value encodes alignment. */ @@ -687,27 +729,38 @@ static void simplify_symbols(Elf_Shdr *s } /* Now try to resolve undefined symbols */ - for (sym = (void *)sechdrs[symindex].sh_offset, i = 0; - i < sechdrs[symindex].sh_size / sizeof(Elf_Sym); - i++) { - if (sym[i].st_shndx == SHN_UNDEF) { - /* Look for symbol */ - struct kernel_symbol_group *ksg = NULL; - const char *strtab - = (char *)sechdrs[strindex].sh_offset; + for (i = 0; i < sechdrs[symindex].sh_size / sizeof(Elf_Sym); i++) { + struct kernel_symbol_group *ksg = NULL; + const char *strtab = (char *)sechdrs[strindex].sh_offset; - sym[i].st_value - = find_symbol_internal(sechdrs, - symindex, - strtab, - strtab + sym[i].st_name, - mod, - &ksg); - /* We fake up "__this_module" */ - if (strcmp(strtab+sym[i].st_name, "__this_module")==0) - sym[i].st_value = (unsigned long)mod; + if (sym[i].st_shndx != SHN_UNDEF) + continue; + + /* Look for symbol */ + sym[i].st_value + = find_symbol_internal(sechdrs, + symindex, + strtab, + strtab + sym[i].st_name, + mod, + &ksg); + + if (sym[i].st_value && ksg == &kernel_symbols) { + ret = check_version(mod->name, + strtab + sym[i].st_name, + (void *)sechdrs[versindex] + .sh_offset, + sechdrs[versindex].sh_size + / sizeof(struct modversion_info)); + if (ret != 0) + return ret; } + + /* We fake up "__this_module" */ + if (streq(strtab+sym[i].st_name, "__this_module")) + sym[i].st_value = (unsigned long)mod; } + return 0; } /* Get the total allocation size of the init and non-init sections */ @@ -748,7 +801,7 @@ static struct module *load_module(void * Elf_Shdr *sechdrs; char *secstrings; unsigned int i, symindex, exportindex, strindex, setupindex, exindex, - modnameindex, obsparmindex; + modnameindex, obsparmindex, versindex; long arglen; unsigned long common_length; struct sizes sizes, used; @@ -786,7 +839,7 @@ 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 = versindex = 0; /* And these should exist, but gcc whinges if we don't init them */ symindex = strindex = exindex = modnameindex = 0; @@ -827,6 +880,11 @@ 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, ".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 */ @@ -913,7 +971,18 @@ static struct module *load_module(void * BUG(); /* Fix up syms, so that st_value is a pointer to location. */ - simplify_symbols(sechdrs, symindex, strindex, mod->module_core, mod); + err = simplify_symbols(sechdrs, symindex, strindex, versindex, + 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 + / sizeof(struct modversion_info)); + if (err < 0) + goto cleanup; /* Set up EXPORTed symbols */ if (exportindex) { diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .3225-linux-2.5.38/kernel/modversions.c .3225-linux-2.5.38.updated/kernel/modversions.c --- .3225-linux-2.5.38/kernel/modversions.c 1970-01-01 10:00:00.000000000 +1000 +++ .3225-linux-2.5.38.updated/kernel/modversions.c 2002-09-25 07:34:34.000000000 +1000 @@ -0,0 +1,13 @@ +/* Made very late: not referred to be normal makefiles. + (C) Copyright 2002 Rusty Russell, IBM Corporation. +*/ +#include +struct modversion_info modversions[] __attribute__((section(".versions"))) = { +#include +#ifdef CONFIG_SMP + { "__SMP__", 1 }, +#else + { "__SMP__", 0 }, +#endif + { "", 0 } +}; diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .3225-linux-2.5.38/scripts/add_versions .3225-linux-2.5.38.updated/scripts/add_versions --- .3225-linux-2.5.38/scripts/add_versions 1970-01-01 10:00:00.000000000 +1000 +++ .3225-linux-2.5.38.updated/scripts/add_versions 2002-09-25 07:34:34.000000000 +1000 @@ -0,0 +1,32 @@ +#! /bin/sh +# For a given list of modules, add a .versions section containing the +# versions it expects. + +set -e + +if [ $# -lt 1 ]; then + echo Usage: add_versions extraversion objfiles... >&2 + exit 1 +fi + +EXTRAVERSION=$1 +shift 1 + +for file; do + trap "rm -f .$file.versions.*" 0 + $NM -u $file | sed 's/$.*$/"\1",/' | sort | join -1 1 -2 2 -o 2.1,1.1,2.3,2.4 - $TOPDIR/include/linux/generated-modversions.h > .$file.versions + if [ -s .$file.versions ]; then + echo "Adding versions to $RELDIR/$file" + echo '#include ' > .$file.versions.c + echo 'struct modversion_info __modversions[] __attribute__((section(".versions"))) = {' >> .$file.versions.c + cat .$file.versions >> .$file.versions.c + echo "$EXTRAVERSION" >> .$file.versions.c + echo '};' >> .$file.versions.c + # Remove old .versions section, won't be required once Makefiles work. + $OBJCOPY --remove-section=.versions $file .$file.versions.none.o + # Compile and add .versions section. + $CC $CFLAGS -c .$file.versions.c + $LD $LDFLAGS -r -o $file .$file.versions.none.o .$file.versions.o + fi + rm -f .$file.versions.* +done diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .3225-linux-2.5.38/scripts/extract_versions .3225-linux-2.5.38.updated/scripts/extract_versions --- .3225-linux-2.5.38/scripts/extract_versions 1970-01-01 10:00:00.000000000 +1000 +++ .3225-linux-2.5.38.updated/scripts/extract_versions 2002-09-25 07:34:34.000000000 +1000 @@ -0,0 +1,23 @@ +#! /bin/sh +# Given a list of object files, output the C structure for the version table. + +set -e + +if [ $# -lt 2 ]; then + echo Usage: extract_versions kernelversion objfiles... >&2 + exit 1 +fi + +VERSION=$1 +shift 1 + +# Join 16-lines into one big filename, then run each filename through genksyms. +# Genksyms produces: +# #define __ver_printk smp_1b7d4074 +# #define printk _set_ver(printk) +# +# And since it's outside the kernel source tree, we use sed on it. +for file in `"$OBJDUMP" --section=.needmodversion --full-contents "$@" | sed -n '/^ *[0-9a-fA-Z][0-9a-fA-Z][0-9a-fA-Z][0-9a-fA-Z] /{N;N;N;N;N;N;N;N;N;N;N;N;N;N;N;s/[0-9A-Za-z ]* //g;s/\n//g;s/\.*$//gp;}' | sort -u`; do + echo "GENKSYMS $file" >&2 + $CPP $CFLAGS -D__GENKSYMS__ $file | genksyms -k $VERSION | sed -n '/#define __ver_/{s///;N;s/\n.*//;s/$[a-zA-Z0-9_]*$[^a-zA-Z0-9_]*$.*$/{ "\1", 0x\2 },/p;}' +done | sort -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell. - 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/