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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-09-11 04:34:46 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-09-11 04:34:46 -0300
commit863981e96738983919de841ec669e157e6bdaeb0 (patch)
treed6d89a12e7eb8017837c057935a2271290907f76 /kernel/module.c
parent8dec7c70575785729a6a9e6719a955e9c545bcab (diff)
Linux-libre 4.7.1-gnupck-4.7.1-gnu
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c125
1 files changed, 122 insertions, 3 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 041200ca4..5f71aa63e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1973,6 +1973,83 @@ static void module_enable_nx(const struct module *mod) { }
static void module_disable_nx(const struct module *mod) { }
#endif
+#ifdef CONFIG_LIVEPATCH
+/*
+ * Persist Elf information about a module. Copy the Elf header,
+ * section header table, section string table, and symtab section
+ * index from info to mod->klp_info.
+ */
+static int copy_module_elf(struct module *mod, struct load_info *info)
+{
+ unsigned int size, symndx;
+ int ret;
+
+ size = sizeof(*mod->klp_info);
+ mod->klp_info = kmalloc(size, GFP_KERNEL);
+ if (mod->klp_info == NULL)
+ return -ENOMEM;
+
+ /* Elf header */
+ size = sizeof(mod->klp_info->hdr);
+ memcpy(&mod->klp_info->hdr, info->hdr, size);
+
+ /* Elf section header table */
+ size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
+ mod->klp_info->sechdrs = kmalloc(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);
+ 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;
+ mod->klp_info->symndx = symndx;
+
+ /*
+ * For livepatch modules, core_kallsyms.symtab is a complete
+ * copy of the original symbol table. Adjust sh_addr to point
+ * to core_kallsyms.symtab since the copy of the symtab in module
+ * init memory is freed at the end of do_init_module().
+ */
+ mod->klp_info->sechdrs[symndx].sh_addr = \
+ (unsigned long) mod->core_kallsyms.symtab;
+
+ return 0;
+
+free_sechdrs:
+ kfree(mod->klp_info->sechdrs);
+free_info:
+ kfree(mod->klp_info);
+ return ret;
+}
+
+static void free_module_elf(struct module *mod)
+{
+ kfree(mod->klp_info->sechdrs);
+ kfree(mod->klp_info->secstrings);
+ kfree(mod->klp_info);
+}
+#else /* !CONFIG_LIVEPATCH */
+static int copy_module_elf(struct module *mod, struct load_info *info)
+{
+ return 0;
+}
+
+static void free_module_elf(struct module *mod)
+{
+}
+#endif /* CONFIG_LIVEPATCH */
+
void __weak module_memfree(void *module_region)
{
vfree(module_region);
@@ -2011,6 +2088,9 @@ static void free_module(struct module *mod)
/* Free any allocated parameters. */
destroy_params(mod->kp, mod->num_kp);
+ if (is_livepatch_module(mod))
+ free_module_elf(mod);
+
/* Now we can delete it from the lists */
mutex_lock(&module_mutex);
/* Unlink carefully: kallsyms could be walking list. */
@@ -2126,6 +2206,10 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)
(long)sym[i].st_value);
break;
+ case SHN_LIVEPATCH:
+ /* Livepatch symbols are resolved by livepatch */
+ break;
+
case SHN_UNDEF:
ksym = resolve_symbol_wait(mod, info, name);
/* Ok if resolved. */
@@ -2174,6 +2258,10 @@ static int apply_relocations(struct module *mod, const struct load_info *info)
if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
continue;
+ /* Livepatch relocation sections are applied by livepatch */
+ if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
+ continue;
+
if (info->sechdrs[i].sh_type == SHT_REL)
err = apply_relocate(info->sechdrs, info->strtab,
info->index.sym, i, mod);
@@ -2469,7 +2557,7 @@ static void layout_symtab(struct module *mod, struct load_info *info)
/* Compute total space required for the core symbols' strtab. */
for (ndst = i = 0; i < nsrc; i++) {
- if (i == 0 ||
+ if (i == 0 || is_livepatch_module(mod) ||
is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum,
info->index.pcpu)) {
strtab_size += strlen(&info->strtab[src[i].st_name])+1;
@@ -2528,7 +2616,7 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
mod->core_kallsyms.strtab = s = mod->core_layout.base + info->stroffs;
src = mod->kallsyms->symtab;
for (ndst = i = 0; i < mod->kallsyms->num_symtab; i++) {
- if (i == 0 ||
+ if (i == 0 || is_livepatch_module(mod) ||
is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum,
info->index.pcpu)) {
dst[ndst] = src[i];
@@ -2667,6 +2755,26 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l
return 0;
}
+#ifdef CONFIG_LIVEPATCH
+static int find_livepatch_modinfo(struct module *mod, struct load_info *info)
+{
+ mod->klp = get_modinfo(info, "livepatch") ? true : false;
+
+ return 0;
+}
+#else /* !CONFIG_LIVEPATCH */
+static int find_livepatch_modinfo(struct module *mod, struct load_info *info)
+{
+ if (get_modinfo(info, "livepatch")) {
+ pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
+ mod->name);
+ return -ENOEXEC;
+ }
+
+ return 0;
+}
+#endif /* CONFIG_LIVEPATCH */
+
/* Sets info->hdr and info->len. */
static int copy_module_from_user(const void __user *umod, unsigned long len,
struct load_info *info)
@@ -2821,6 +2929,10 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
"is unknown, you have been warned.\n", mod->name);
}
+ err = find_livepatch_modinfo(mod, info);
+ if (err)
+ return err;
+
/* Set up license info based on the info section */
set_license(mod, get_modinfo(info, "license"));
@@ -3494,6 +3606,12 @@ static int load_module(struct load_info *info, const char __user *uargs,
if (err < 0)
goto coming_cleanup;
+ if (is_livepatch_module(mod)) {
+ err = copy_module_elf(mod, info);
+ if (err < 0)
+ goto sysfs_cleanup;
+ }
+
/* Get rid of temporary copy. */
free_copy(info);
@@ -3502,11 +3620,12 @@ static int load_module(struct load_info *info, const char __user *uargs,
return do_init_module(mod);
+ sysfs_cleanup:
+ mod_sysfs_teardown(mod);
coming_cleanup:
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
klp_module_going(mod);
-
bug_cleanup:
/* module_bug_cleanup needs module_mutex protection */
mutex_lock(&module_mutex);