module: move module args strndup_user to just before use

Instead of copying and allocating the args and storing it in
load_info, we can just allocate them right before we need them.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 13 insertions, 15 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 29dd232f8183..cabafe228444 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -114,7 +114,7 @@ struct load_info {
         Elf_Ehdr *hdr;
         unsigned long len;
         Elf_Shdr *sechdrs;
-        char *secstrings, *args, *strtab;
+        char *secstrings, *strtab;
         unsigned long *strmap;
         unsigned long symoffs, stroffs;
         struct {
@@ -2096,7 +2096,7 @@ static inline void kmemleak_load_module(const struct module *mod,
 }
 #endif
 
-/* Sets info->hdr, info->len and info->args. */
+/* Sets info->hdr and info->len. */
 static int copy_and_check(struct load_info *info,
                           const void __user *umod, unsigned long len,
                           const char __user *uargs)
@@ -2132,13 +2132,6 @@ static int copy_and_check(struct load_info *info,
                 goto free_hdr;
         }
 
-        /* Now copy in args */
-        info->args = strndup_user(uargs, ~0UL >> 1);
-        if (IS_ERR(info->args)) {
-                err = PTR_ERR(info->args);
-                goto free_hdr;
-        }
-
         info->hdr = hdr;
         info->len = len;
         return 0;
@@ -2150,7 +2143,6 @@ free_hdr:
 
 static void free_copy(struct load_info *info)
 {
-        kfree(info->args);
         vfree(info->hdr);
 }
 
@@ -2468,7 +2460,7 @@ static struct module *layout_and_allocate(struct load_info *info)
         err = module_frob_arch_sections(info->hdr, info->sechdrs,
                                         info->secstrings, mod);
         if (err < 0)
-                goto free_args;
+                goto out;
 
         pcpusec = &info->sechdrs[info->index.pcpu];
         if (pcpusec->sh_size) {
@@ -2476,7 +2468,7 @@ static struct module *layout_and_allocate(struct load_info *info)
                 err = percpu_modalloc(mod,
                                       pcpusec->sh_size, pcpusec->sh_addralign);
                 if (err)
-                        goto free_args;
+                        goto out;
                 pcpusec->sh_flags &= ~(unsigned long)SHF_ALLOC;
         }
 
@@ -2507,8 +2499,7 @@ free_strmap:
         kfree(info->strmap);
 free_percpu:
         percpu_modfree(mod);
-free_args:
-        kfree(info->args);
+out:
         return ERR_PTR(err);
 }
 
@@ -2594,7 +2585,12 @@ static noinline struct module *load_module(void __user *umod,
 
         flush_module_icache(mod);
 
-        mod->args = info.args;
+        /* Now copy in args */
+        mod->args = strndup_user(uargs, ~0UL >> 1);
+        if (IS_ERR(mod->args)) {
+                err = PTR_ERR(mod->args);
+                goto free_arch_cleanup;
+        }
 
         mod->state = MODULE_STATE_COMING;
 
@@ -2648,6 +2644,8 @@ static noinline struct module *load_module(void __user *umod,
  unlock:
         mutex_unlock(&module_mutex);
         synchronize_sched();
+        kfree(mod->args);
+ free_arch_cleanup:
         module_arch_cleanup(mod);
  free_modinfo:
         free_modinfo(mod);