If we pass a pointer to a const string in the form "module:symbol"
module_kallsyms_lookup_name() will try to split the string at the colon,
i.e., will try to modify r/o data. That will, in fact, fail on a kernel
with enabled CONFIG_DEBUG_RODATA.
Avoid modifying the passed string in module_kallsyms_lookup_name(),
modify find_module_all() instead to pass it the module name length.
Signed-off-by: Mathias Krause <mini...@googlemail.com>
---
v2:
- don't use kstrdup(), pass the string length to find_module_all() as
suggested by Rusty
kernel/module.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index cab4bce..bf3b846 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -455,7 +455,7 @@ const struct kernel_symbol *find_symbol(const char *name,
EXPORT_SYMBOL_GPL(find_symbol);
/* Search for module by name: must hold module_mutex. */
-static struct module *find_module_all(const char *name,
+static struct module *find_module_all(const char *name, size_t len,
bool even_unformed)
{
struct module *mod;
@@ -463,7 +463,7 @@ static struct module *find_module_all(const char *name,
list_for_each_entry(mod, &modules, list) {
if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
continue;
- if (strcmp(mod->name, name) == 0)
+ if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
return mod;
}
return NULL;
@@ -471,7 +471,7 @@ static struct module *find_module_all(const char *name,
struct module *find_module(const char *name)
{
- return find_module_all(name, false);
+ return find_module_all(name, strlen(name), false);
}
EXPORT_SYMBOL_GPL(find_module);
@@ -3014,7 +3014,7 @@ static bool finished_loading(const char *name)
bool ret;
mutex_lock(&module_mutex);
- mod = find_module_all(name, true);
+ mod = find_module_all(name, strlen(name), true);
ret = !mod || mod->state == MODULE_STATE_LIVE
|| mod->state == MODULE_STATE_GOING;
mutex_unlock(&module_mutex);
@@ -3152,7 +3152,8 @@ static int add_unformed_module(struct module *mod)
again:
mutex_lock(&module_mutex);
- if ((old = find_module_all(mod->name, true)) != NULL) {
+ old = find_module_all(mod->name, strlen(mod->name), true);
+ if (old != NULL) {
if (old->state == MODULE_STATE_COMING
|| old->state == MODULE_STATE_UNFORMED) {
/* Wait in case it fails to load. */
@@ -3563,10 +3564,8 @@ unsigned long module_kallsyms_lookup_name(const char
*name)
/* Don't lock: we're in enough trouble already. */
preempt_disable();
if ((colon = strchr(name, ':')) != NULL) {
- *colon = '\0';
- if ((mod = find_module(name)) != NULL)
+ if ((mod = find_module_all(name, colon - name, false)) != NULL)
ret = mod_find_symname(mod, colon+1);
- *colon = ':';
} else {
list_for_each_entry_rcu(mod, &modules, list) {
if (mod->state == MODULE_STATE_UNFORMED)
--
1.7.10.4
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