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>

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>
Rusty Russell
1 parent 49668688dd
Showing 1 changed file with 13 additions and 15 deletions Side-by-side Diff
kernel/module.c
@@ -114,7 +114,7 @@
 	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 @@
 }
 #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 @@
 		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 @@
  
 static void free_copy(struct load_info *info)
 {
-	kfree(info->args);
 	vfree(info->hdr);
 }
  
@@ -2468,7 +2460,7 @@
 	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 @@
 		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 @@
 	kfree(info->strmap);
 free_percpu:
 	percpu_modfree(mod);
-free_args:
-	kfree(info->args);
+out:
 	return ERR_PTR(err);
 }
  
@@ -2594,7 +2585,12 @@
  
 	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 @@
  unlock:
 	mutex_unlock(&module_mutex);
 	synchronize_sched();
+	kfree(mod->args);
+ free_arch_cleanup:
 	module_arch_cleanup(mod);
  free_modinfo:
 	free_modinfo(mod);
...	...	@@ -114,7 +114,7 @@
114	114	Elf_Ehdr *hdr;
115	115	unsigned long len;
116	116	Elf_Shdr *sechdrs;
117		- char secstrings, args, *strtab;
	117	+ char secstrings, strtab;
118	118	unsigned long *strmap;
119	119	unsigned long symoffs, stroffs;
120	120	struct {
...	...	@@ -2096,7 +2096,7 @@
2096	2096	}
2097	2097	#endif
2098	2098
2099		-/* Sets info->hdr, info->len and info->args. */
	2099	+/* Sets info->hdr and info->len. */
2100	2100	static int copy_and_check(struct load_info *info,
2101	2101	const void __user *umod, unsigned long len,
2102	2102	const char __user *uargs)
...	...	@@ -2132,13 +2132,6 @@
2132	2132	goto free_hdr;
2133	2133	}
2134	2134
2135		- /* Now copy in args */
2136		- info->args = strndup_user(uargs, ~0UL >> 1);
2137		- if (IS_ERR(info->args)) {
2138		- err = PTR_ERR(info->args);
2139		- goto free_hdr;
2140		- }
2141		-
2142	2135	info->hdr = hdr;
2143	2136	info->len = len;
2144	2137	return 0;
...	...	@@ -2150,7 +2143,6 @@
2150	2143
2151	2144	static void free_copy(struct load_info *info)
2152	2145	{
2153		- kfree(info->args);
2154	2146	vfree(info->hdr);
2155	2147	}
2156	2148
...	...	@@ -2468,7 +2460,7 @@
2468	2460	err = module_frob_arch_sections(info->hdr, info->sechdrs,
2469	2461	info->secstrings, mod);
2470	2462	if (err < 0)
2471		- goto free_args;
	2463	+ goto out;
2472	2464
2473	2465	pcpusec = &info->sechdrs[info->index.pcpu];
2474	2466	if (pcpusec->sh_size) {
...	...	@@ -2476,7 +2468,7 @@
2476	2468	err = percpu_modalloc(mod,
2477	2469	pcpusec->sh_size, pcpusec->sh_addralign);
2478	2470	if (err)
2479		- goto free_args;
	2471	+ goto out;
2480	2472	pcpusec->sh_flags &= ~(unsigned long)SHF_ALLOC;
2481	2473	}
2482	2474
...	...	@@ -2507,8 +2499,7 @@
2507	2499	kfree(info->strmap);
2508	2500	free_percpu:
2509	2501	percpu_modfree(mod);
2510		-free_args:
2511		- kfree(info->args);
	2502	+out:
2512	2503	return ERR_PTR(err);
2513	2504	}
2514	2505
...	...	@@ -2594,7 +2585,12 @@
2594	2585
2595	2586	flush_module_icache(mod);
2596	2587
2597		- mod->args = info.args;
	2588	+ /* Now copy in args */
	2589	+ mod->args = strndup_user(uargs, ~0UL >> 1);
	2590	+ if (IS_ERR(mod->args)) {
	2591	+ err = PTR_ERR(mod->args);
	2592	+ goto free_arch_cleanup;
	2593	+ }
2598	2594
2599	2595	mod->state = MODULE_STATE_COMING;
2600	2596
...	...	@@ -2648,6 +2644,8 @@
2648	2644	unlock:
2649	2645	mutex_unlock(&module_mutex);
2650	2646	synchronize_sched();
	2647	+ kfree(mod->args);
	2648	+ free_arch_cleanup:
2651	2649	module_arch_cleanup(mod);
2652	2650	free_modinfo:
2653	2651	free_modinfo(mod);