summaryrefslogtreecommitdiffstats
path: root/kernel/module.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2018-08-17 10:51:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-17 10:51:22 -0700
commitd190775206d06397a9309421cac5ba2f2c243521 (patch)
tree60f1fd84e6dd55cefb906382b26eba31b4f1ad71 /kernel/module.c
parent84f5685230c6aeb427947a2299dcb54c77863df0 (diff)
parent9be936f4b3a2ec101f54cff9cf1a6abf67263c50 (diff)
downloadlinux-d190775206d06397a9309421cac5ba2f2c243521.tar.bz2
Merge tag 'modules-for-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu: "Summary of modules changes for the 4.19 merge window: - Fix modules kallsyms for livepatch. Livepatch modules can have SHN_UNDEF symbols in their module symbol tables for later symbol resolution, but kallsyms shouldn't be returning these symbols - Some code cleanups and minor reshuffling in load_module() were done to log the module name when module signature verification fails" * tag 'modules-for-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: kernel/module: Use kmemdup to replace kmalloc+memcpy ARM: module: fix modsign build error modsign: log module name in the event of an error module: replace VMLINUX_SYMBOL_STR() with __stringify() or string literal module: print sensible error code module: setup load info before module_sig_check() module: make it clear when we're handling the module copy in info->hdr module: exclude SHN_UNDEF symbols from kallsyms api
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c143
1 files changed, 66 insertions, 77 deletions
diff --git a/kernel/module.c b/kernel/module.c
index a7615d661910..b046a32520d8 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -307,24 +307,6 @@ int unregister_module_notifier(struct notifier_block *nb)
}
EXPORT_SYMBOL(unregister_module_notifier);
-struct load_info {
- const char *name;
- Elf_Ehdr *hdr;
- unsigned long len;
- Elf_Shdr *sechdrs;
- char *secstrings, *strtab;
- unsigned long symoffs, stroffs;
- struct _ddebug *debug;
- unsigned int num_debug;
- bool sig_ok;
-#ifdef CONFIG_KALLSYMS
- unsigned long mod_kallsyms_init_off;
-#endif
- struct {
- unsigned int sym, str, mod, vers, info, pcpu;
- } index;
-};
-
/*
* We require a truly strong try_module_get(): 0 means success.
* Otherwise an error is returned due to ongoing or failed
@@ -1339,14 +1321,12 @@ static inline int check_modstruct_version(const struct load_info *info,
* locking is necessary -- use preempt_disable() to placate lockdep.
*/
preempt_disable();
- if (!find_symbol(VMLINUX_SYMBOL_STR(module_layout), NULL,
- &crc, true, false)) {
+ if (!find_symbol("module_layout", NULL, &crc, true, false)) {
preempt_enable();
BUG();
}
preempt_enable();
- return check_version(info, VMLINUX_SYMBOL_STR(module_layout),
- mod, crc);
+ return check_version(info, "module_layout", mod, crc);
}
/* First part is kernel version, which we ignore if module has crcs. */
@@ -2059,21 +2039,19 @@ static int copy_module_elf(struct module *mod, struct load_info *info)
/* Elf section header table */
size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
- mod->klp_info->sechdrs = kmalloc(size, GFP_KERNEL);
+ mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
if (mod->klp_info->sechdrs == NULL) {
ret = -ENOMEM;
goto free_info;
}
- memcpy(mod->klp_info->sechdrs, info->sechdrs, size);
/* Elf section name string table */
size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
- mod->klp_info->secstrings = kmalloc(size, GFP_KERNEL);
+ mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
if (mod->klp_info->secstrings == NULL) {
ret = -ENOMEM;
goto free_sechdrs;
}
- memcpy(mod->klp_info->secstrings, info->secstrings, size);
/* Elf symbol section index */
symndx = info->index.sym;
@@ -2282,9 +2260,9 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)
if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
break;
- pr_warn("%s: Unknown symbol %s (err %li)\n",
- mod->name, name, PTR_ERR(ksym));
ret = PTR_ERR(ksym) ?: -ENOENT;
+ pr_warn("%s: Unknown symbol %s (err %d)\n",
+ mod->name, name, ret);
break;
default:
@@ -2486,7 +2464,11 @@ static char *get_modinfo(struct load_info *info, const char *tag)
Elf_Shdr *infosec = &info->sechdrs[info->index.info];
unsigned long size = infosec->sh_size;
- for (p = (char *)infosec->sh_addr; p; p = next_string(p, &size)) {
+ /*
+ * get_modinfo() calls made before rewrite_section_headers()
+ * must use sh_offset, as sh_addr isn't set!
+ */
+ for (p = (char *)info->hdr + infosec->sh_offset; p; p = next_string(p, &size)) {
if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
return p + taglen + 1;
}
@@ -2774,7 +2756,7 @@ static int module_sig_check(struct load_info *info, int flags)
memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
/* We truncate the module to discard the signature */
info->len -= markerlen;
- err = mod_verify_sig(mod, &info->len);
+ err = mod_verify_sig(mod, info);
}
if (!err) {
@@ -2926,17 +2908,7 @@ static int rewrite_section_headers(struct load_info *info, int flags)
}
/* Track but don't keep modinfo and version sections. */
- if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
- info->index.vers = 0; /* Pretend no __versions section! */
- else
- info->index.vers = find_sec(info, "__versions");
info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
-
- info->index.info = find_sec(info, ".modinfo");
- if (!info->index.info)
- info->name = "(missing .modinfo section)";
- else
- info->name = get_modinfo(info, "name");
info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
return 0;
@@ -2947,23 +2919,24 @@ static int rewrite_section_headers(struct load_info *info, int flags)
* search for module section index etc), and do some basic section
* verification.
*
- * Return the temporary module pointer (we'll replace it with the final
- * one when we move the module sections around).
+ * Set info->mod to the temporary copy of the module in info->hdr. The final one
+ * will be allocated in move_module().
*/
-static struct module *setup_load_info(struct load_info *info, int flags)
+static int setup_load_info(struct load_info *info, int flags)
{
unsigned int i;
- int err;
- struct module *mod;
/* Set up the convenience variables */
info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
info->secstrings = (void *)info->hdr
+ info->sechdrs[info->hdr->e_shstrndx].sh_offset;
- err = rewrite_section_headers(info, flags);
- if (err)
- return ERR_PTR(err);
+ /* Try to find a name early so we can log errors with a module name */
+ info->index.info = find_sec(info, ".modinfo");
+ if (!info->index.info)
+ info->name = "(missing .modinfo section)";
+ else
+ info->name = get_modinfo(info, "name");
/* Find internal symbols and strings. */
for (i = 1; i < info->hdr->e_shnum; i++) {
@@ -2976,34 +2949,35 @@ static struct module *setup_load_info(struct load_info *info, int flags)
}
}
+ if (info->index.sym == 0) {
+ pr_warn("%s: module has no symbols (stripped?)\n", info->name);
+ return -ENOEXEC;
+ }
+
info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
if (!info->index.mod) {
pr_warn("%s: No module found in object\n",
info->name ?: "(missing .modinfo name field)");
- return ERR_PTR(-ENOEXEC);
+ return -ENOEXEC;
}
/* This is temporary: point mod into copy of data. */
- mod = (void *)info->sechdrs[info->index.mod].sh_addr;
+ info->mod = (void *)info->hdr + info->sechdrs[info->index.mod].sh_offset;
/*
- * If we didn't load the .modinfo 'name' field, fall back to
+ * If we didn't load the .modinfo 'name' field earlier, fall back to
* on-disk struct mod 'name' field.
*/
if (!info->name)
- info->name = mod->name;
+ info->name = info->mod->name;
- if (info->index.sym == 0) {
- pr_warn("%s: module has no symbols (stripped?)\n", info->name);
- return ERR_PTR(-ENOEXEC);
- }
+ if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
+ info->index.vers = 0; /* Pretend no __versions section! */
+ else
+ info->index.vers = find_sec(info, "__versions");
info->index.pcpu = find_pcpusec(info);
- /* Check module struct version now, before we try to use module. */
- if (!check_modstruct_version(info, mod))
- return ERR_PTR(-ENOEXEC);
-
- return mod;
+ return 0;
}
static int check_modinfo(struct module *mod, struct load_info *info, int flags)
@@ -3298,25 +3272,17 @@ core_param(module_blacklist, module_blacklist, charp, 0400);
static struct module *layout_and_allocate(struct load_info *info, int flags)
{
- /* Module within temporary copy. */
struct module *mod;
unsigned int ndx;
int err;
- mod = setup_load_info(info, flags);
- if (IS_ERR(mod))
- return mod;
-
- if (blacklisted(info->name))
- return ERR_PTR(-EPERM);
-
- err = check_modinfo(mod, info, flags);
+ err = check_modinfo(info->mod, info, flags);
if (err)
return ERR_PTR(err);
/* Allow arches to frob section contents and sizes. */
err = module_frob_arch_sections(info->hdr, info->sechdrs,
- info->secstrings, mod);
+ info->secstrings, info->mod);
if (err < 0)
return ERR_PTR(err);
@@ -3335,11 +3301,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
/* Determine total sizes, and put offsets in sh_entsize. For now
this is done generically; there doesn't appear to be any
special cases for the architectures. */
- layout_sections(mod, info);
- layout_symtab(mod, info);
+ layout_sections(info->mod, info);
+ layout_symtab(info->mod, info);
/* Allocate and move to the final place */
- err = move_module(mod, info);
+ err = move_module(info->mod, info);
if (err)
return ERR_PTR(err);
@@ -3657,17 +3623,36 @@ static int load_module(struct load_info *info, const char __user *uargs,
int flags)
{
struct module *mod;
- long err;
+ long err = 0;
char *after_dashes;
+ err = elf_header_check(info);
+ if (err)
+ goto free_copy;
+
+ err = setup_load_info(info, flags);
+ if (err)
+ goto free_copy;
+
+ if (blacklisted(info->name)) {
+ err = -EPERM;
+ goto free_copy;
+ }
+
err = module_sig_check(info, flags);
if (err)
goto free_copy;
- err = elf_header_check(info);
+ err = rewrite_section_headers(info, flags);
if (err)
goto free_copy;
+ /* Check module struct version now, before we try to use module. */
+ if (!check_modstruct_version(info, info->mod)) {
+ err = -ENOEXEC;
+ goto free_copy;
+ }
+
/* Figure out module layout, and allocate all the memory. */
mod = layout_and_allocate(info, flags);
if (IS_ERR(mod)) {
@@ -4067,7 +4052,7 @@ static unsigned long mod_find_symname(struct module *mod, const char *name)
for (i = 0; i < kallsyms->num_symtab; i++)
if (strcmp(name, symname(kallsyms, i)) == 0 &&
- kallsyms->symtab[i].st_info != 'U')
+ kallsyms->symtab[i].st_shndx != SHN_UNDEF)
return kallsyms->symtab[i].st_value;
return 0;
}
@@ -4113,6 +4098,10 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
if (mod->state == MODULE_STATE_UNFORMED)
continue;
for (i = 0; i < kallsyms->num_symtab; i++) {
+
+ if (kallsyms->symtab[i].st_shndx == SHN_UNDEF)
+ continue;
+
ret = fn(data, symname(kallsyms, i),
mod, kallsyms->symtab[i].st_value);
if (ret != 0)