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authorLinus Torvalds <torvalds@linux-foundation.org>2012-12-19 07:55:08 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-19 07:55:08 -0800
commit7a684c452e2589f3ddd7e2d466b4f747d3715ad9 (patch)
treefed803e7450770993575b37807ba2195eafd5b0e /kernel/module.c
parent7f2de8171ddf28fdb2ca7f9a683ee1207849f718 (diff)
parente10e1774efbdaec54698454200619a03a01e1d64 (diff)
downloadlinux-linaro-stable-7a684c452e2589f3ddd7e2d466b4f747d3715ad9.tar.gz
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.c441
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)