param: check for tainting before calling set op.

This means every set op doesn't need to call it, and it can move into
params.c.

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

2 files changed, 11 insertions, 27 deletions

diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 9531f9f9729e..593501996574 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -374,22 +374,6 @@ static inline void destroy_params(const struct kernel_param *params,
 #define __param_check(name, p, type) \
         static inline type __always_unused *__check_##name(void) { return(p); }
 
-/**
- * param_check_unsafe - Warn and taint the kernel if setting dangerous options.
- *
- * This gets called from all the standard param setters, but can be used from
- * custom setters as well.
- */
-static inline void
-param_check_unsafe(const struct kernel_param *kp)
-{
-        if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
-                pr_warn("Setting dangerous option %s - tainting kernel\n",
-                        kp->name);
-                add_taint(TAINT_USER, LOCKDEP_STILL_OK);
-        }
-}
-
 extern struct kernel_param_ops param_ops_byte;
 extern int param_set_byte(const char *val, const struct kernel_param *kp);
 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
diff --git a/kernel/params.c b/kernel/params.c
index ad8d04563c3a..041b5899d5e2 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -83,6 +83,15 @@ bool parameq(const char *a, const char *b)
         return parameqn(a, b, strlen(a)+1);
 }
 
+static void param_check_unsafe(const struct kernel_param *kp)
+{
+        if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
+                pr_warn("Setting dangerous option %s - tainting kernel\n",
+                        kp->name);
+                add_taint(TAINT_USER, LOCKDEP_STILL_OK);
+        }
+}
+
 static int parse_one(char *param,
                      char *val,
                      const char *doing,
@@ -109,6 +118,7 @@ static int parse_one(char *param,
                         pr_debug("handling %s with %p\n", param,
                                 params[i].ops->set);
                         mutex_lock(&param_lock);
+                        param_check_unsafe(&params[i]);
                         err = params[i].ops->set(val, &params[i]);
                         mutex_unlock(&param_lock);
                         return err;
@@ -233,7 +243,6 @@ char *parse_args(const char *doing,
 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)                \
         int param_set_##name(const char *val, const struct kernel_param *kp) \
         {                                                               \
-                param_check_unsafe(kp);                                 \
                 return strtolfn(val, 0, (type *)kp->arg);               \
         }                                                               \
         int param_get_##name(char *buffer, const struct kernel_param *kp) \
@@ -266,8 +275,6 @@ int param_set_charp(const char *val, const struct kernel_param *kp)
                 return -ENOSPC;
         }
 
-        param_check_unsafe(kp);
-
         maybe_kfree_parameter(*(char **)kp->arg);
 
         /* This is a hack.  We can't kmalloc in early boot, and we
@@ -305,8 +312,6 @@ EXPORT_SYMBOL(param_ops_charp);
 /* Actually could be a bool or an int, for historical reasons. */
 int param_set_bool(const char *val, const struct kernel_param *kp)
 {
-        param_check_unsafe(kp);
-
         /* No equals means "set"... */
         if (!val) val = "1";
 
@@ -336,8 +341,6 @@ int param_set_invbool(const char *val, const struct kernel_param *kp)
         bool boolval;
         struct kernel_param dummy;
 
-        param_check_unsafe(kp);
-
         dummy.arg = &boolval;
         ret = param_set_bool(val, &dummy);
         if (ret == 0)
@@ -364,8 +367,6 @@ int param_set_bint(const char *val, const struct kernel_param *kp)
         bool v;
         int ret;
 
-        param_check_unsafe(kp);
-
         /* Match bool exactly, by re-using it. */
         boolkp = *kp;
         boolkp.arg = &v;
@@ -485,8 +486,6 @@ int param_set_copystring(const char *val, const struct kernel_param *kp)
 {
         const struct kparam_string *kps = kp->str;
 
-        param_check_unsafe(kp);
-
         if (strlen(val)+1 > kps->maxlen) {
                 pr_err("%s: string doesn't fit in %u chars.\n",
                        kp->name, kps->maxlen-1);
@@ -563,6 +562,7 @@ static ssize_t param_attr_store(struct module_attribute *mattr,
                 return -EPERM;
 
         mutex_lock(&param_lock);
+        param_check_unsafe(attribute->param);
         err = attribute->param->ops->set(buf, attribute->param);
         mutex_unlock(&param_lock);
         if (!err)