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SubjectRe: [patch] kernel/module.c
Andrew Mortom wrote:
>
> There are two bugs in sys_init_module():

And I added another.

Let's try again, without the memory leak.




--- linux-2.4.0-test7/kernel/module.c Tue Jul 11 22:21:17 2000
+++ linux-akpm/kernel/module.c Sun Aug 27 03:38:02 2000
@@ -6,6 +6,7 @@
#include <linux/smp_lock.h>
#include <asm/pgalloc.h>
#include <linux/init.h>
+#include <linux/slab.h>

/*
* Originally by Anonymous (as far as I know...)
@@ -26,6 +27,10 @@
extern const struct exception_table_entry __start___ex_table[];
extern const struct exception_table_entry __stop___ex_table[];

+/*
+ * Don't turn this initialiser into "name: value," form.
+ * gcc-2.7.2.3 lays it out incorrectly (andrewm@uow.edu.au)
+ */
static struct module kernel_module =
{
sizeof(struct module), /* size_of_struct */
@@ -160,7 +165,7 @@
sys_init_module(const char *name_user, struct module *mod_user)
{
struct module mod_tmp, *mod;
- char *name, *n_name;
+ char *name, *n_name, *name_tmp = 0;
long namelen, n_namelen, i, error;
unsigned long mod_user_size;
struct module_ref *dep;
@@ -194,6 +199,12 @@
/* Hold the current contents while we play with the user's idea
of righteousness. */
mod_tmp = *mod;
+ name_tmp = kmalloc(strlen(mod->name) + 1, GFP_KERNEL); /* Where's kstrdup()? */
+ if (name_tmp == NULL) {
+ error = -ENOMEM;
+ goto err1;
+ }
+ strcpy(name_tmp, mod->name);

error = copy_from_user(mod, mod_user, sizeof(struct module));
if (error) {
@@ -290,9 +301,10 @@
to make the I and D caches consistent. */
flush_icache_range((unsigned long)mod, (unsigned long)mod + mod->size);

- /* Update module references. */
mod->next = mod_tmp.next;
mod->refs = NULL;
+
+ /* Sanity check the module's dependents */
for (i = 0, dep = mod->deps; i < mod->ndeps; ++i, ++dep) {
struct module *o, *d = dep->dep;

@@ -303,14 +315,21 @@
goto err3;
}

- for (o = module_list; o != &kernel_module; o = o->next)
- if (o == d) goto found_dep;
+ /* Scan the current modules for this dependency */
+ for (o = module_list; o != &kernel_module && o != d; o = o->next)
+ ;

- printk(KERN_ERR "init_module: found dependency that is "
+ if (o != d) {
+ printk(KERN_ERR "init_module: found dependency that is "
"(no longer?) a module.\n");
- goto err3;
-
- found_dep:
+ goto err3;
+ }
+ }
+
+ /* Update module references. */
+ for (i = 0, dep = mod->deps; i < mod->ndeps; ++i, ++dep) {
+ struct module *d = dep->dep;
+
dep->ref = mod;
dep->next_ref = d->refs;
d->refs = dep;
@@ -344,10 +363,14 @@
put_mod_name(n_name);
err2:
*mod = mod_tmp;
+ strcpy((char *)mod->name, name_tmp); /* We know there is room for this */
+ name_tmp = 0;
err1:
put_mod_name(name);
err0:
unlock_kernel();
+ if (name_tmp)
+ kfree(name_tmp);
return error;
}
-
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