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authorLinus Torvalds <torvalds@linux-foundation.org>2018-12-27 12:08:33 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-27 12:08:33 -0800
commit7f9f852c75e7d776b078813586c76a2bc7dca993 (patch)
tree1870d8ce5b3a6b3b964a3d9cddf2c75e896fc61a /kernel/module.c
parent3f03bf93947fa2a2b84fac56e93c65d4fffed7f1 (diff)
parent93d77e7f1410c366050d6035dcba1a5167c7cf0b (diff)
Merge tag 'modules-for-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu: - Some modules-related kallsyms cleanups and a kallsyms fix for ARM. - Include keys from the secondary keyring in module signature verification. * tag 'modules-for-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: ARM: module: Fix function kallsyms on Thumb-2 module: Overwrite st_size instead of st_info module: make it clearer when we're handling kallsyms symbols vs exported symbols modsign: use all trusted keys to verify module signature
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c123
1 files changed, 72 insertions, 51 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 99b46c32d579..339b3cd39dd4 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -495,9 +495,9 @@ struct find_symbol_arg {
const struct kernel_symbol *sym;
};
-static bool check_symbol(const struct symsearch *syms,
- struct module *owner,
- unsigned int symnum, void *data)
+static bool check_exported_symbol(const struct symsearch *syms,
+ struct module *owner,
+ unsigned int symnum, void *data)
{
struct find_symbol_arg *fsa = data;
@@ -555,9 +555,9 @@ static int cmp_name(const void *va, const void *vb)
return strcmp(a, kernel_symbol_name(b));
}
-static bool find_symbol_in_section(const struct symsearch *syms,
- struct module *owner,
- void *data)
+static bool find_exported_symbol_in_section(const struct symsearch *syms,
+ struct module *owner,
+ void *data)
{
struct find_symbol_arg *fsa = data;
struct kernel_symbol *sym;
@@ -565,13 +565,14 @@ static bool find_symbol_in_section(const struct symsearch *syms,
sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
sizeof(struct kernel_symbol), cmp_name);
- if (sym != NULL && check_symbol(syms, owner, sym - syms->start, data))
+ if (sym != NULL && check_exported_symbol(syms, owner,
+ sym - syms->start, data))
return true;
return false;
}
-/* Find a symbol and return it, along with, (optional) crc and
+/* Find an exported symbol and return it, along with, (optional) crc and
* (optional) module which owns it. Needs preempt disabled or module_mutex. */
const struct kernel_symbol *find_symbol(const char *name,
struct module **owner,
@@ -585,7 +586,7 @@ const struct kernel_symbol *find_symbol(const char *name,
fsa.gplok = gplok;
fsa.warn = warn;
- if (each_symbol_section(find_symbol_in_section, &fsa)) {
+ if (each_symbol_section(find_exported_symbol_in_section, &fsa)) {
if (owner)
*owner = fsa.owner;
if (crc)
@@ -2198,7 +2199,7 @@ EXPORT_SYMBOL_GPL(__symbol_get);
*
* You must hold the module_mutex.
*/
-static int verify_export_symbols(struct module *mod)
+static int verify_exported_symbols(struct module *mod)
{
unsigned int i;
struct module *owner;
@@ -2519,10 +2520,10 @@ static void free_modinfo(struct module *mod)
#ifdef CONFIG_KALLSYMS
-/* lookup symbol in given range of kernel_symbols */
-static const struct kernel_symbol *lookup_symbol(const char *name,
- const struct kernel_symbol *start,
- const struct kernel_symbol *stop)
+/* Lookup exported symbol in given range of kernel_symbols */
+static const struct kernel_symbol *lookup_exported_symbol(const char *name,
+ const struct kernel_symbol *start,
+ const struct kernel_symbol *stop)
{
return bsearch(name, start, stop - start,
sizeof(struct kernel_symbol), cmp_name);
@@ -2533,9 +2534,10 @@ static int is_exported(const char *name, unsigned long value,
{
const struct kernel_symbol *ks;
if (!mod)
- ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
+ ks = lookup_exported_symbol(name, __start___ksymtab, __stop___ksymtab);
else
- ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
+ ks = lookup_exported_symbol(name, mod->syms, mod->syms + mod->num_syms);
+
return ks != NULL && kernel_symbol_value(ks) == value;
}
@@ -2682,7 +2684,7 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
/* Set types up while we still have access to sections. */
for (i = 0; i < mod->kallsyms->num_symtab; i++)
- mod->kallsyms->symtab[i].st_info
+ mod->kallsyms->symtab[i].st_size
= elf_type(&mod->kallsyms->symtab[i], info);
/* Now populate the cut down core kallsyms for after init. */
@@ -3592,7 +3594,7 @@ static int complete_formation(struct module *mod, struct load_info *info)
mutex_lock(&module_mutex);
/* Find duplicate symbols (must be called under lock). */
- err = verify_export_symbols(mod);
+ err = verify_exported_symbols(mod);
if (err < 0)
goto out;
@@ -3911,18 +3913,22 @@ static inline int is_arm_mapping_symbol(const char *str)
&& (str[2] == '\0' || str[2] == '.');
}
-static const char *symname(struct mod_kallsyms *kallsyms, unsigned int symnum)
+static const char *kallsyms_symbol_name(struct mod_kallsyms *kallsyms, unsigned int symnum)
{
return kallsyms->strtab + kallsyms->symtab[symnum].st_name;
}
-static const char *get_ksymbol(struct module *mod,
- unsigned long addr,
- unsigned long *size,
- unsigned long *offset)
+/*
+ * Given a module and address, find the corresponding symbol and return its name
+ * while providing its size and offset if needed.
+ */
+static const char *find_kallsyms_symbol(struct module *mod,
+ unsigned long addr,
+ unsigned long *size,
+ unsigned long *offset)
{
unsigned int i, best = 0;
- unsigned long nextval;
+ unsigned long nextval, bestval;
struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
/* At worse, next value is at end of module */
@@ -3931,34 +3937,40 @@ static const char *get_ksymbol(struct module *mod,
else
nextval = (unsigned long)mod->core_layout.base+mod->core_layout.text_size;
+ bestval = kallsyms_symbol_value(&kallsyms->symtab[best]);
+
/* Scan for closest preceding symbol, and next symbol. (ELF
starts real symbols at 1). */
for (i = 1; i < kallsyms->num_symtab; i++) {
- if (kallsyms->symtab[i].st_shndx == SHN_UNDEF)
+ const Elf_Sym *sym = &kallsyms->symtab[i];
+ unsigned long thisval = kallsyms_symbol_value(sym);
+
+ if (sym->st_shndx == SHN_UNDEF)
continue;
/* We ignore unnamed symbols: they're uninformative
* and inserted at a whim. */
- if (*symname(kallsyms, i) == '\0'
- || is_arm_mapping_symbol(symname(kallsyms, i)))
+ if (*kallsyms_symbol_name(kallsyms, i) == '\0'
+ || is_arm_mapping_symbol(kallsyms_symbol_name(kallsyms, i)))
continue;
- if (kallsyms->symtab[i].st_value <= addr
- && kallsyms->symtab[i].st_value > kallsyms->symtab[best].st_value)
+ if (thisval <= addr && thisval > bestval) {
best = i;
- if (kallsyms->symtab[i].st_value > addr
- && kallsyms->symtab[i].st_value < nextval)
- nextval = kallsyms->symtab[i].st_value;
+ bestval = thisval;
+ }
+ if (thisval > addr && thisval < nextval)
+ nextval = thisval;
}
if (!best)
return NULL;
if (size)
- *size = nextval - kallsyms->symtab[best].st_value;
+ *size = nextval - bestval;
if (offset)
- *offset = addr - kallsyms->symtab[best].st_value;
- return symname(kallsyms, best);
+ *offset = addr - bestval;
+
+ return kallsyms_symbol_name(kallsyms, best);
}
void * __weak dereference_module_function_descriptor(struct module *mod,
@@ -3983,7 +3995,8 @@ const char *module_address_lookup(unsigned long addr,
if (mod) {
if (modname)
*modname = mod->name;
- ret = get_ksymbol(mod, addr, size, offset);
+
+ ret = find_kallsyms_symbol(mod, addr, size, offset);
}
/* Make a copy in here where it's safe */
if (ret) {
@@ -4006,9 +4019,10 @@ int lookup_module_symbol_name(unsigned long addr, char *symname)
if (within_module(addr, mod)) {
const char *sym;
- sym = get_ksymbol(mod, addr, NULL, NULL);
+ sym = find_kallsyms_symbol(mod, addr, NULL, NULL);
if (!sym)
goto out;
+
strlcpy(symname, sym, KSYM_NAME_LEN);
preempt_enable();
return 0;
@@ -4031,7 +4045,7 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
if (within_module(addr, mod)) {
const char *sym;
- sym = get_ksymbol(mod, addr, size, offset);
+ sym = find_kallsyms_symbol(mod, addr, size, offset);
if (!sym)
goto out;
if (modname)
@@ -4060,9 +4074,11 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
continue;
kallsyms = rcu_dereference_sched(mod->kallsyms);
if (symnum < kallsyms->num_symtab) {
- *value = kallsyms->symtab[symnum].st_value;
- *type = kallsyms->symtab[symnum].st_info;
- strlcpy(name, symname(kallsyms, symnum), KSYM_NAME_LEN);
+ const Elf_Sym *sym = &kallsyms->symtab[symnum];
+
+ *value = kallsyms_symbol_value(sym);
+ *type = sym->st_size;
+ strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN);
strlcpy(module_name, mod->name, MODULE_NAME_LEN);
*exported = is_exported(name, *value, mod);
preempt_enable();
@@ -4074,15 +4090,19 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
return -ERANGE;
}
-static unsigned long mod_find_symname(struct module *mod, const char *name)
+/* Given a module and name of symbol, find and return the symbol's value */
+static unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name)
{
unsigned int i;
struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
- for (i = 0; i < kallsyms->num_symtab; i++)
- if (strcmp(name, symname(kallsyms, i)) == 0 &&
- kallsyms->symtab[i].st_shndx != SHN_UNDEF)
- return kallsyms->symtab[i].st_value;
+ for (i = 0; i < kallsyms->num_symtab; i++) {
+ const Elf_Sym *sym = &kallsyms->symtab[i];
+
+ if (strcmp(name, kallsyms_symbol_name(kallsyms, i)) == 0 &&
+ sym->st_shndx != SHN_UNDEF)
+ return kallsyms_symbol_value(sym);
+ }
return 0;
}
@@ -4097,12 +4117,12 @@ unsigned long module_kallsyms_lookup_name(const char *name)
preempt_disable();
if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
if ((mod = find_module_all(name, colon - name, false)) != NULL)
- ret = mod_find_symname(mod, colon+1);
+ ret = find_kallsyms_symbol_value(mod, colon+1);
} else {
list_for_each_entry_rcu(mod, &modules, list) {
if (mod->state == MODULE_STATE_UNFORMED)
continue;
- if ((ret = mod_find_symname(mod, name)) != 0)
+ if ((ret = find_kallsyms_symbol_value(mod, name)) != 0)
break;
}
}
@@ -4127,12 +4147,13 @@ 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++) {
+ const Elf_Sym *sym = &kallsyms->symtab[i];
- if (kallsyms->symtab[i].st_shndx == SHN_UNDEF)
+ if (sym->st_shndx == SHN_UNDEF)
continue;
- ret = fn(data, symname(kallsyms, i),
- mod, kallsyms->symtab[i].st_value);
+ ret = fn(data, kallsyms_symbol_name(kallsyms, i),
+ mod, kallsyms_symbol_value(sym));
if (ret != 0)
return ret;
}