[PATCH RFC] [2/9] Fix duplicate symbol check to also check future gpl and unused symbols

Andi Kleen
2007-11-22T02:43:55Z

This seems to have been forgotten earlier. Right now it was possible
for a normal symbol to override a future gpl symbol and similar.
I restructured the code a bit to avoid too much duplicated code.

---
kernel/module.c | 45 ++++++++++++++++++++++++---------------------
1 file changed, 24 insertions(+), 21 deletions(-)

Index: linux/kernel/module.c
===================================================================
--- linux.orig/kernel/module.c
+++ linux/kernel/module.c
@@ -1430,33 +1430,36 @@ EXPORT_SYMBOL_GPL(do_symbol_get);
* Ensure that an exported symbol [global namespace] does not already exist
* in the kernel or in some other module's exported symbol table.
*/
-static int verify_export_symbols(struct module *mod)
+
+static int check_duplicate(const struct kernel_symbol *syms, int num, struct module *owner)
{
- const char *name = NULL;
- unsigned long i, ret = 0;
- struct module *owner;
+ int i;
const unsigned long *crc;

- for (i = 0; i < mod->num_syms; i++)
- if (find_symbol(mod->syms[i].name, &owner, &crc, 1, mod)) {
- name = mod->syms[i].name;
- ret = -ENOEXEC;
- goto dup;
- }
-
- for (i = 0; i < mod->num_gpl_syms; i++)
- if (find_symbol(mod->gpl_syms[i].name, &owner, &crc, 1, mod)) {
- name = mod->gpl_syms[i].name;
- ret = -ENOEXEC;
- goto dup;
+ for (i = 0; i < num; i++)
+ if (find_symbol(syms[i].name, &owner, &crc, 1, owner)) {
+ printk(KERN_ERR "%s: exports duplicate symbol %s (owned by %s)\n",
+ owner->name, syms[i].name, module_name(owner));
+ return -ENOEXEC;
}
+ return 0;
+}

-dup:
+static int verify_export_symbols(struct module *mod)
+{
+ int ret = check_duplicate(mod->syms, mod->num_syms, mod);
if (ret)
- printk(KERN_ERR "%s: exports duplicate symbol %s (owned by %s)\n",
- mod->name, name, module_name(owner));
-
- return ret;
+ return ret;
+ ret = check_duplicate(mod->gpl_syms, mod->num_gpl_syms, mod);
+ if (ret)
+ return ret;
+ ret = check_duplicate(mod->unused_syms, mod->num_unused_syms, mod);
+ if (ret)
+ return ret;
+ ret = check_duplicate(mod->unused_gpl_syms, mod->num_unused_gpl_syms, mod);
+ if (ret)
+ return ret;
+ return check_duplicate(mod->gpl_future_syms, mod->num_gpl_future_syms, mod);
}

/* Change all symbols so that sh_value encodes the pointer directly. */