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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-19 16:55:08 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-19 16:55:08 +0100 |
commit | 7a684c452e2589f3ddd7e2d466b4f747d3715ad9 (patch) | |
tree | fed803e7450770993575b37807ba2195eafd5b0e /kernel/module.c | |
parent | Merge tag 'byteswap-for-linus-20121219' of git://git.infradead.org/users/dwmw... (diff) | |
parent | MODSIGN: Fix kbuild output when using default extra_certificates (diff) | |
download | linux-7a684c452e2589f3ddd7e2d466b4f747d3715ad9.tar.xz linux-7a684c452e2589f3ddd7e2d466b4f747d3715ad9.zip |
Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull module update from Rusty Russell:
"Nothing all that exciting; a new module-from-fd syscall for those who
want to verify the source of the module (ChromeOS) and/or use standard
IMA on it or other security hooks."
* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
MODSIGN: Fix kbuild output when using default extra_certificates
MODSIGN: Avoid using .incbin in C source
modules: don't hand 0 to vmalloc.
module: Remove a extra null character at the top of module->strtab.
ASN.1: Use the ASN1_LONG_TAG and ASN1_INDEFINITE_LENGTH constants
ASN.1: Define indefinite length marker constant
moduleparam: use __UNIQUE_ID()
__UNIQUE_ID()
MODSIGN: Add modules_sign make target
powerpc: add finit_module syscall.
ima: support new kernel module syscall
add finit_module syscall to asm-generic
ARM: add finit_module syscall to ARM
security: introduce kernel_module_from_file hook
module: add flags arg to sys_finit_module()
module: add syscall to load module from fd
Diffstat (limited to 'kernel/module.c')
-rw-r--r-- | kernel/module.c | 441 |
1 files changed, 267 insertions, 174 deletions
diff --git a/kernel/module.c b/kernel/module.c index 808bd62e1723..250092c1d57d 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -21,6 +21,7 @@ #include <linux/ftrace_event.h> #include <linux/init.h> #include <linux/kallsyms.h> +#include <linux/file.h> #include <linux/fs.h> #include <linux/sysfs.h> #include <linux/kernel.h> @@ -28,6 +29,7 @@ #include <linux/vmalloc.h> #include <linux/elf.h> #include <linux/proc_fs.h> +#include <linux/security.h> #include <linux/seq_file.h> #include <linux/syscalls.h> #include <linux/fcntl.h> @@ -59,6 +61,7 @@ #include <linux/pfn.h> #include <linux/bsearch.h> #include <linux/fips.h> +#include <uapi/linux/module.h> #include "module-internal.h" #define CREATE_TRACE_POINTS @@ -2279,7 +2282,7 @@ static void layout_symtab(struct module *mod, struct load_info *info) Elf_Shdr *symsect = info->sechdrs + info->index.sym; Elf_Shdr *strsect = info->sechdrs + info->index.str; const Elf_Sym *src; - unsigned int i, nsrc, ndst, strtab_size; + unsigned int i, nsrc, ndst, strtab_size = 0; /* Put symbol section at end of init part of module. */ symsect->sh_flags |= SHF_ALLOC; @@ -2290,9 +2293,6 @@ static void layout_symtab(struct module *mod, struct load_info *info) src = (void *)info->hdr + symsect->sh_offset; nsrc = symsect->sh_size / sizeof(*src); - /* strtab always starts with a nul, so offset 0 is the empty string. */ - strtab_size = 1; - /* Compute total space required for the core symbols' strtab. */ for (ndst = i = 0; i < nsrc; i++) { if (i == 0 || @@ -2334,7 +2334,6 @@ static void add_kallsyms(struct module *mod, const struct load_info *info) mod->core_symtab = dst = mod->module_core + info->symoffs; mod->core_strtab = s = mod->module_core + info->stroffs; src = mod->symtab; - *s++ = 0; for (ndst = i = 0; i < mod->num_symtab; i++) { if (i == 0 || is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) { @@ -2375,7 +2374,7 @@ static void dynamic_debug_remove(struct _ddebug *debug) void * __weak module_alloc(unsigned long size) { - return size == 0 ? NULL : vmalloc_exec(size); + return vmalloc_exec(size); } static void *module_alloc_update_bounds(unsigned long size) @@ -2422,18 +2421,17 @@ static inline void kmemleak_load_module(const struct module *mod, #endif #ifdef CONFIG_MODULE_SIG -static int module_sig_check(struct load_info *info, - const void *mod, unsigned long *_len) +static int module_sig_check(struct load_info *info) { int err = -ENOKEY; - unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; - unsigned long len = *_len; + const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; + const void *mod = info->hdr; - if (len > markerlen && - memcmp(mod + len - markerlen, MODULE_SIG_STRING, markerlen) == 0) { + if (info->len > markerlen && + memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) { /* We truncate the module to discard the signature */ - *_len -= markerlen; - err = mod_verify_sig(mod, _len); + info->len -= markerlen; + err = mod_verify_sig(mod, &info->len); } if (!err) { @@ -2451,59 +2449,107 @@ static int module_sig_check(struct load_info *info, return err; } #else /* !CONFIG_MODULE_SIG */ -static int module_sig_check(struct load_info *info, - void *mod, unsigned long *len) +static int module_sig_check(struct load_info *info) { return 0; } #endif /* !CONFIG_MODULE_SIG */ -/* Sets info->hdr, info->len and info->sig_ok. */ -static int copy_and_check(struct load_info *info, - const void __user *umod, unsigned long len, - const char __user *uargs) +/* Sanity checks against invalid binaries, wrong arch, weird elf version. */ +static int elf_header_check(struct load_info *info) +{ + if (info->len < sizeof(*(info->hdr))) + return -ENOEXEC; + + if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0 + || info->hdr->e_type != ET_REL + || !elf_check_arch(info->hdr) + || info->hdr->e_shentsize != sizeof(Elf_Shdr)) + return -ENOEXEC; + + if (info->hdr->e_shoff >= info->len + || (info->hdr->e_shnum * sizeof(Elf_Shdr) > + info->len - info->hdr->e_shoff)) + return -ENOEXEC; + + return 0; +} + +/* Sets info->hdr and info->len. */ +static int copy_module_from_user(const void __user *umod, unsigned long len, + struct load_info *info) { int err; - Elf_Ehdr *hdr; - if (len < sizeof(*hdr)) + info->len = len; + if (info->len < sizeof(*(info->hdr))) return -ENOEXEC; + err = security_kernel_module_from_file(NULL); + if (err) + return err; + /* Suck in entire file: we'll want most of it. */ - if ((hdr = vmalloc(len)) == NULL) + info->hdr = vmalloc(info->len); + if (!info->hdr) return -ENOMEM; - if (copy_from_user(hdr, umod, len) != 0) { - err = -EFAULT; - goto free_hdr; + if (copy_from_user(info->hdr, umod, info->len) != 0) { + vfree(info->hdr); + return -EFAULT; } - err = module_sig_check(info, hdr, &len); + return 0; +} + +/* Sets info->hdr and info->len. */ +static int copy_module_from_fd(int fd, struct load_info *info) +{ + struct file *file; + int err; + struct kstat stat; + loff_t pos; + ssize_t bytes = 0; + + file = fget(fd); + if (!file) + return -ENOEXEC; + + err = security_kernel_module_from_file(file); if (err) - goto free_hdr; + goto out; - /* Sanity checks against insmoding binaries or wrong arch, - weird elf version */ - if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0 - || hdr->e_type != ET_REL - || !elf_check_arch(hdr) - || hdr->e_shentsize != sizeof(Elf_Shdr)) { - err = -ENOEXEC; - goto free_hdr; - } + err = vfs_getattr(file->f_vfsmnt, file->f_dentry, &stat); + if (err) + goto out; - if (hdr->e_shoff >= len || - hdr->e_shnum * sizeof(Elf_Shdr) > len - hdr->e_shoff) { - err = -ENOEXEC; - goto free_hdr; + if (stat.size > INT_MAX) { + err = -EFBIG; + goto out; + } + info->hdr = vmalloc(stat.size); + if (!info->hdr) { + err = -ENOMEM; + goto out; } - info->hdr = hdr; - info->len = len; - return 0; + pos = 0; + while (pos < stat.size) { + bytes = kernel_read(file, pos, (char *)(info->hdr) + pos, + stat.size - pos); + if (bytes < 0) { + vfree(info->hdr); + err = bytes; + goto out; + } + if (bytes == 0) + break; + pos += bytes; + } + info->len = pos; -free_hdr: - vfree(hdr); +out: + fput(file); return err; } @@ -2512,7 +2558,7 @@ static void free_copy(struct load_info *info) vfree(info->hdr); } -static int rewrite_section_headers(struct load_info *info) +static int rewrite_section_headers(struct load_info *info, int flags) { unsigned int i; @@ -2540,7 +2586,10 @@ static int rewrite_section_headers(struct load_info *info) } /* Track but don't keep modinfo and version sections. */ - info->index.vers = find_sec(info, "__versions"); + if (flags & MODULE_INIT_IGNORE_MODVERSIONS) + info->index.vers = 0; /* Pretend no __versions section! */ + else + info->index.vers = find_sec(info, "__versions"); info->index.info = find_sec(info, ".modinfo"); info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC; info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC; @@ -2555,7 +2604,7 @@ static int rewrite_section_headers(struct load_info *info) * Return the temporary module pointer (we'll replace it with the final * one when we move the module sections around). */ -static struct module *setup_load_info(struct load_info *info) +static struct module *setup_load_info(struct load_info *info, int flags) { unsigned int i; int err; @@ -2566,7 +2615,7 @@ static struct module *setup_load_info(struct load_info *info) info->secstrings = (void *)info->hdr + info->sechdrs[info->hdr->e_shstrndx].sh_offset; - err = rewrite_section_headers(info); + err = rewrite_section_headers(info, flags); if (err) return ERR_PTR(err); @@ -2604,11 +2653,14 @@ static struct module *setup_load_info(struct load_info *info) return mod; } -static int check_modinfo(struct module *mod, struct load_info *info) +static int check_modinfo(struct module *mod, struct load_info *info, int flags) { const char *modmagic = get_modinfo(info, "vermagic"); int err; + if (flags & MODULE_INIT_IGNORE_VERMAGIC) + modmagic = NULL; + /* This is allowed: modprobe --force will invalidate it. */ if (!modmagic) { err = try_to_force_load(mod, "bad vermagic"); @@ -2738,20 +2790,23 @@ static int move_module(struct module *mod, struct load_info *info) memset(ptr, 0, mod->core_size); mod->module_core = ptr; - ptr = module_alloc_update_bounds(mod->init_size); - /* - * The pointer to this block is stored in the module structure - * which is inside the block. This block doesn't need to be - * scanned as it contains data and code that will be freed - * after the module is initialized. - */ - kmemleak_ignore(ptr); - if (!ptr && mod->init_size) { - module_free(mod, mod->module_core); - return -ENOMEM; - } - memset(ptr, 0, mod->init_size); - mod->module_init = ptr; + if (mod->init_size) { + ptr = module_alloc_update_bounds(mod->init_size); + /* + * The pointer to this block is stored in the module structure + * which is inside the block. This block doesn't need to be + * scanned as it contains data and code that will be freed + * after the module is initialized. + */ + kmemleak_ignore(ptr); + if (!ptr) { + module_free(mod, mod->module_core); + return -ENOMEM; + } + memset(ptr, 0, mod->init_size); + mod->module_init = ptr; + } else + mod->module_init = NULL; /* Transfer each section which specifies SHF_ALLOC */ pr_debug("final section addresses:\n"); @@ -2844,18 +2899,18 @@ int __weak module_frob_arch_sections(Elf_Ehdr *hdr, return 0; } -static struct module *layout_and_allocate(struct load_info *info) +static struct module *layout_and_allocate(struct load_info *info, int flags) { /* Module within temporary copy. */ struct module *mod; Elf_Shdr *pcpusec; int err; - mod = setup_load_info(info); + mod = setup_load_info(info, flags); if (IS_ERR(mod)) return mod; - err = check_modinfo(mod, info); + err = check_modinfo(mod, info, flags); if (err) return ERR_PTR(err); @@ -2942,33 +2997,124 @@ static bool finished_loading(const char *name) return ret; } +/* Call module constructors. */ +static void do_mod_ctors(struct module *mod) +{ +#ifdef CONFIG_CONSTRUCTORS + unsigned long i; + + for (i = 0; i < mod->num_ctors; i++) + mod->ctors[i](); +#endif +} + +/* This is where the real work happens */ +static int do_init_module(struct module *mod) +{ + int ret = 0; + + blocking_notifier_call_chain(&module_notify_list, + MODULE_STATE_COMING, mod); + + /* Set RO and NX regions for core */ + set_section_ro_nx(mod->module_core, + mod->core_text_size, + mod->core_ro_size, + mod->core_size); + + /* Set RO and NX regions for init */ + set_section_ro_nx(mod->module_init, + mod->init_text_size, + mod->init_ro_size, + mod->init_size); + + do_mod_ctors(mod); + /* Start the module */ + if (mod->init != NULL) + ret = do_one_initcall(mod->init); + if (ret < 0) { + /* Init routine failed: abort. Try to protect us from + buggy refcounters. */ + mod->state = MODULE_STATE_GOING; + synchronize_sched(); + module_put(mod); + blocking_notifier_call_chain(&module_notify_list, + MODULE_STATE_GOING, mod); + free_module(mod); + wake_up_all(&module_wq); + return ret; + } + if (ret > 0) { + printk(KERN_WARNING +"%s: '%s'->init suspiciously returned %d, it should follow 0/-E convention\n" +"%s: loading module anyway...\n", + __func__, mod->name, ret, + __func__); + dump_stack(); + } + + /* Now it's a first class citizen! */ + mod->state = MODULE_STATE_LIVE; + blocking_notifier_call_chain(&module_notify_list, + MODULE_STATE_LIVE, mod); + + /* We need to finish all async code before the module init sequence is done */ + async_synchronize_full(); + + mutex_lock(&module_mutex); + /* Drop initial reference. */ + module_put(mod); + trim_init_extable(mod); +#ifdef CONFIG_KALLSYMS + mod->num_symtab = mod->core_num_syms; + mod->symtab = mod->core_symtab; + mod->strtab = mod->core_strtab; +#endif + unset_module_init_ro_nx(mod); + module_free(mod, mod->module_init); + mod->module_init = NULL; + mod->init_size = 0; + mod->init_ro_size = 0; + mod->init_text_size = 0; + mutex_unlock(&module_mutex); + wake_up_all(&module_wq); + + return 0; +} + +static int may_init_module(void) +{ + if (!capable(CAP_SYS_MODULE) || modules_disabled) + return -EPERM; + + return 0; +} + /* 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 __user *umod, - unsigned long len, - const char __user *uargs) +static int load_module(struct load_info *info, const char __user *uargs, + int flags) { - struct load_info info = { NULL, }; struct module *mod, *old; long err; - pr_debug("load_module: umod=%p, len=%lu, uargs=%p\n", - umod, len, uargs); + err = module_sig_check(info); + if (err) + goto free_copy; - /* Copy in the blobs from userspace, check they are vaguely sane. */ - err = copy_and_check(&info, umod, len, uargs); + err = elf_header_check(info); if (err) - return ERR_PTR(err); + goto free_copy; /* Figure out module layout, and allocate all the memory. */ - mod = layout_and_allocate(&info); + mod = layout_and_allocate(info, flags); if (IS_ERR(mod)) { err = PTR_ERR(mod); goto free_copy; } #ifdef CONFIG_MODULE_SIG - mod->sig_ok = info.sig_ok; + mod->sig_ok = info->sig_ok; if (!mod->sig_ok) add_taint_module(mod, TAINT_FORCED_MODULE); #endif @@ -2980,25 +3126,25 @@ static struct module *load_module(void __user *umod, /* Now we've got everything in the final locations, we can * find optional sections. */ - find_module_sections(mod, &info); + find_module_sections(mod, info); err = check_module_license_and_versions(mod); if (err) goto free_unload; /* Set up MODINFO_ATTR fields */ - setup_modinfo(mod, &info); + setup_modinfo(mod, info); /* Fix up syms, so that st_value is a pointer to location. */ - err = simplify_symbols(mod, &info); + err = simplify_symbols(mod, info); if (err < 0) goto free_modinfo; - err = apply_relocations(mod, &info); + err = apply_relocations(mod, info); if (err < 0) goto free_modinfo; - err = post_relocation(mod, &info); + err = post_relocation(mod, info); if (err < 0) goto free_modinfo; @@ -3038,14 +3184,14 @@ again: } /* This has to be done once we're sure module name is unique. */ - dynamic_debug_setup(info.debug, info.num_debug); + dynamic_debug_setup(info->debug, info->num_debug); /* Find duplicate symbols */ err = verify_export_symbols(mod); if (err < 0) goto ddebug; - module_bug_finalize(info.hdr, info.sechdrs, mod); + module_bug_finalize(info->hdr, info->sechdrs, mod); list_add_rcu(&mod->list, &modules); mutex_unlock(&module_mutex); @@ -3056,16 +3202,17 @@ again: goto unlink; /* Link in to syfs. */ - err = mod_sysfs_setup(mod, &info, mod->kp, mod->num_kp); + err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp); if (err < 0) goto unlink; /* Get rid of temporary copy. */ - free_copy(&info); + free_copy(info); /* Done! */ trace_module_load(mod); - return mod; + + return do_init_module(mod); unlink: mutex_lock(&module_mutex); @@ -3074,7 +3221,7 @@ again: module_bug_cleanup(mod); wake_up_all(&module_wq); ddebug: - dynamic_debug_remove(info.debug); + dynamic_debug_remove(info->debug); unlock: mutex_unlock(&module_mutex); synchronize_sched(); @@ -3086,106 +3233,52 @@ again: free_unload: module_unload_free(mod); free_module: - module_deallocate(mod, &info); + module_deallocate(mod, info); free_copy: - free_copy(&info); - return ERR_PTR(err); -} - -/* Call module constructors. */ -static void do_mod_ctors(struct module *mod) -{ -#ifdef CONFIG_CONSTRUCTORS - unsigned long i; - - for (i = 0; i < mod->num_ctors; i++) - mod->ctors[i](); -#endif + free_copy(info); + return err; } -/* This is where the real work happens */ SYSCALL_DEFINE3(init_module, void __user *, umod, unsigned long, len, const char __user *, uargs) { - struct module *mod; - int ret = 0; + int err; + struct load_info info = { }; - /* Must have permission */ - if (!capable(CAP_SYS_MODULE) || modules_disabled) - return -EPERM; + err = may_init_module(); + if (err) + return err; - /* Do all the hard work */ - mod = load_module(umod, len, uargs); - if (IS_ERR(mod)) - return PTR_ERR(mod); + pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n", + umod, len, uargs); - blocking_notifier_call_chain(&module_notify_list, - MODULE_STATE_COMING, mod); + err = copy_module_from_user(umod, len, &info); + if (err) + return err; - /* Set RO and NX regions for core */ - set_section_ro_nx(mod->module_core, - mod->core_text_size, - mod->core_ro_size, - mod->core_size); + return load_module(&info, uargs, 0); +} - /* Set RO and NX regions for init */ - set_section_ro_nx(mod->module_init, - mod->init_text_size, - mod->init_ro_size, - mod->init_size); +SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) +{ + int err; + struct load_info info = { }; - do_mod_ctors(mod); - /* Start the module */ - if (mod->init != NULL) - ret = do_one_initcall(mod->init); - if (ret < 0) { - /* Init routine failed: abort. Try to protect us from - buggy refcounters. */ - mod->state = MODULE_STATE_GOING; - synchronize_sched(); - module_put(mod); - blocking_notifier_call_chain(&module_notify_list, - MODULE_STATE_GOING, mod); - free_module(mod); - wake_up_all(&module_wq); - return ret; - } - if (ret > 0) { - printk(KERN_WARNING -"%s: '%s'->init suspiciously returned %d, it should follow 0/-E convention\n" -"%s: loading module anyway...\n", - __func__, mod->name, ret, - __func__); - dump_stack(); - } + err = may_init_module(); + if (err) + return err; - /* Now it's a first class citizen! */ - mod->state = MODULE_STATE_LIVE; - blocking_notifier_call_chain(&module_notify_list, - MODULE_STATE_LIVE, mod); + pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags); - /* We need to finish all async code before the module init sequence is done */ - async_synchronize_full(); + if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS + |MODULE_INIT_IGNORE_VERMAGIC)) + return -EINVAL; - mutex_lock(&module_mutex); - /* Drop initial reference. */ - module_put(mod); - trim_init_extable(mod); -#ifdef CONFIG_KALLSYMS - mod->num_symtab = mod->core_num_syms; - mod->symtab = mod->core_symtab; - mod->strtab = mod->core_strtab; -#endif - unset_module_init_ro_nx(mod); - module_free(mod, mod->module_init); - mod->module_init = NULL; - mod->init_size = 0; - mod->init_ro_size = 0; - mod->init_text_size = 0; - mutex_unlock(&module_mutex); - wake_up_all(&module_wq); + err = copy_module_from_fd(fd, &info); + if (err) + return err; - return 0; + return load_module(&info, uargs, flags); } static inline int within(unsigned long addr, void *start, unsigned long size) |