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authorAlexey Dobriyan <adobriyan@sw.ru>2007-05-08 00:28:39 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:08 -0700
commitea07890a680273b25127129fb555aac0d9324bea (patch)
treeb0742aa5dd90792dc10be3563c1181582d0f5d9e /kernel/module.c
parentae84e324709d6320ed8c1fd7b1736fcbaf26df95 (diff)
downloadlinux-ea07890a680273b25127129fb555aac0d9324bea.tar.gz
Fix race between rmmod and cat /proc/kallsyms
module_get_kallsym() leaks "struct module *" outside of module_mutex which is
no-no, because module can dissapear right after mutex unlock.

Copy all needed information from inside module_mutex into caller-supplied
space.

[bunk@stusta.de: is_exported() can now become static]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/module.c')
-rw-r--r--kernel/module.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/kernel/module.c b/kernel/module.c
index 43a529a1fa48..5ee65994a3bc 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1472,7 +1472,7 @@ static void setup_modinfo(struct module *mod, Elf_Shdr *sechdrs,
 }
 
 #ifdef CONFIG_KALLSYMS
-int is_exported(const char *name, const struct module *mod)
+static int is_exported(const char *name, const struct module *mod)
 {
 	if (!mod && lookup_symbol(name, __start___ksymtab, __stop___ksymtab))
 		return 1;
@@ -2124,8 +2124,8 @@ const char *module_address_lookup(unsigned long addr,
 	return NULL;
 }
 
-struct module *module_get_kallsym(unsigned int symnum, unsigned long *value,
-				char *type, char *name)
+int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
+			char *name, char *module_name, int *exported)
 {
 	struct module *mod;
 
@@ -2136,13 +2136,15 @@ struct module *module_get_kallsym(unsigned int symnum, unsigned long *value,
 			*type = mod->symtab[symnum].st_info;
 			strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
 				KSYM_NAME_LEN + 1);
+			strlcpy(module_name, mod->name, MODULE_NAME_LEN + 1);
+			*exported = is_exported(name, mod);
 			mutex_unlock(&module_mutex);
-			return mod;
+			return 0;
 		}
 		symnum -= mod->num_symtab;
 	}
 	mutex_unlock(&module_mutex);
-	return NULL;
+	return -ERANGE;
 }
 
 static unsigned long mod_find_symname(struct module *mod, const char *name)