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>
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index d086c91..f1ea6f6 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -301,25 +301,20 @@
struct kallsym_iter
{
loff_t pos;
- struct module *owner;
unsigned long value;
unsigned int nameoff; /* If iterating in core kernel symbols */
char type;
char name[KSYM_NAME_LEN+1];
+ char module_name[MODULE_NAME_LEN + 1];
+ int exported;
};
static int get_ksymbol_mod(struct kallsym_iter *iter)
{
- iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms,
- &iter->value, &iter->type,
- iter->name);
- if (iter->owner == NULL)
+ if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value,
+ &iter->type, iter->name, iter->module_name,
+ &iter->exported) < 0)
return 0;
-
- /* Label it "global" if it is exported, "local" if not exported. */
- iter->type = is_exported(iter->name, iter->owner)
- ? toupper(iter->type) : tolower(iter->type);
-
return 1;
}
@@ -328,7 +323,7 @@
{
unsigned off = iter->nameoff;
- iter->owner = NULL;
+ iter->module_name[0] = '\0';
iter->value = kallsyms_addresses[iter->pos];
iter->type = kallsyms_get_symbol_type(off);
@@ -392,12 +387,17 @@
if (!iter->name[0])
return 0;
- if (iter->owner)
+ if (iter->module_name[0]) {
+ char type;
+
+ /* Label it "global" if it is exported,
+ * "local" if not exported. */
+ type = iter->exported ? toupper(iter->type) :
+ tolower(iter->type);
seq_printf(m, "%0*lx %c %s\t[%s]\n",
(int)(2*sizeof(void*)),
- iter->value, iter->type, iter->name,
- module_name(iter->owner));
- else
+ iter->value, type, iter->name, iter->module_name);
+ } else
seq_printf(m, "%0*lx %c %s\n",
(int)(2*sizeof(void*)),
iter->value, iter->type, iter->name);
diff --git a/kernel/module.c b/kernel/module.c
index 43a529a..5ee6599 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1472,7 +1472,7 @@
}
#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 @@
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 @@
*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)