All struct kernel_param_ops .get callbacks have been migrated to using struct seq_buf. Drop the migration scaffolding.
Signed-off-by: Kees Cook <[email protected]> --- include/linux/moduleparam.h | 37 ++-------------------- kernel/params.c | 62 ++++++++++--------------------------- 2 files changed, 20 insertions(+), 79 deletions(-) diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 38acb5aef56b..e6af6f051c93 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -66,15 +66,8 @@ struct kernel_param_ops { /* * Format the parameter's value into @s. Return 0 on success * (length derived from seq_buf_used()) or -errno on error. - * Exactly one of .get and .get_str should be set; the dispatcher - * WARNs and prefers .get if both are. */ int (*get)(struct seq_buf *s, const struct kernel_param *kp); - /* - * Returns length written or -errno. Buffer is 4k (ie. be short!). - * Deprecated: callbacks should implement .get instead. - */ - int (*get_str)(char *buffer, const struct kernel_param *kp); /* Optional function to free kp->arg when module unloaded. */ void (*free)(void *arg); }; @@ -84,33 +77,11 @@ struct kernel_param_ops { * any required visibility qualifiers (typically "static"): * * static DEFINE_KERNEL_PARAM_OPS(my_ops, my_set, my_get); - * - * @_get may be either of: - * int (*)(struct seq_buf *, const struct kernel_param *) (seq_buf) - * int (*)(char *, const struct kernel_param *) (legacy) - * - * The macro uses _Generic to route the function pointer to the - * matching field (.get or .get_str) at compile time, leaving the - * other field NULL. Each helper matches the wrong prototype signature - * and returns NULL, falling through to the default branch otherwise; - * if @_get has neither expected signature the assignment to the - * fields gets a normal compile-time type-mismatch error. */ -#define _KERNEL_PARAM_OPS_GET(_get) \ - _Generic((_get), \ - int (*)(char *, const struct kernel_param *): NULL, \ - default: (_get)) - -#define _KERNEL_PARAM_OPS_GET_STR(_get) \ - _Generic((_get), \ - int (*)(struct seq_buf *, const struct kernel_param *): NULL, \ - default: (_get)) - #define DEFINE_KERNEL_PARAM_OPS(_name, _set, _get) \ const struct kernel_param_ops _name = { \ .set = (_set), \ - .get = _KERNEL_PARAM_OPS_GET(_get), \ - .get_str = _KERNEL_PARAM_OPS_GET_STR(_get), \ + .get = (_get), \ } /* As DEFINE_KERNEL_PARAM_OPS, with KERNEL_PARAM_OPS_FL_NOARG set. */ @@ -118,16 +89,14 @@ struct kernel_param_ops { const struct kernel_param_ops _name = { \ .flags = KERNEL_PARAM_OPS_FL_NOARG, \ .set = (_set), \ - .get = _KERNEL_PARAM_OPS_GET(_get), \ - .get_str = _KERNEL_PARAM_OPS_GET_STR(_get), \ + .get = (_get), \ } /* As DEFINE_KERNEL_PARAM_OPS, with an additional .free callback. */ #define DEFINE_KERNEL_PARAM_OPS_FREE(_name, _set, _get, _free) \ const struct kernel_param_ops _name = { \ .set = (_set), \ - .get = _KERNEL_PARAM_OPS_GET(_get), \ - .get_str = _KERNEL_PARAM_OPS_GET_STR(_get), \ + .get = (_get), \ .free = (_free), \ } diff --git a/kernel/params.c b/kernel/params.c index 25f0c8d5d19f..6b410189297b 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -461,8 +461,7 @@ static int param_array_get(struct seq_buf *s, const struct kernel_param *kp) { const struct kparam_array *arr = kp->arr; struct kernel_param p = *kp; - char *elem_buf = NULL; - int i, ret = 0; + int i, ret; for (i = 0; i < (arr->num ? *arr->num : arr->max); i++) { size_t before = s->len; @@ -470,23 +469,9 @@ static int param_array_get(struct seq_buf *s, const struct kernel_param *kp) p.arg = arr->elem + arr->elemsize * i; check_kparam_locked(p.mod); - if (arr->ops->get) { - ret = arr->ops->get(s, &p); - if (ret < 0) - goto out; - } else { - if (!elem_buf) { - elem_buf = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (!elem_buf) { - ret = -ENOMEM; - goto out; - } - } - ret = arr->ops->get_str(elem_buf, &p); - if (ret < 0) - goto out; - seq_buf_putmem(s, elem_buf, ret); - } + ret = arr->ops->get(s, &p); + if (ret < 0) + return ret; /* Nothing got written (e.g. overflow) — stop. */ if (s->len == before) @@ -496,10 +481,7 @@ static int param_array_get(struct seq_buf *s, const struct kernel_param *kp) if (i && s->buffer[before - 1] == '\n') s->buffer[before - 1] = ','; } - ret = 0; -out: - kfree(elem_buf); - return ret; + return 0; } static void param_array_free(void *arg) @@ -570,32 +552,22 @@ static ssize_t param_attr_show(const struct module_attribute *mattr, int count; const struct param_attribute *attribute = to_param_attr(mattr); const struct kernel_param_ops *ops = attribute->param->ops; + struct seq_buf s; - if (!ops->get && !ops->get_str) + if (!ops->get) return -EPERM; - WARN_ON_ONCE(ops->get && ops->get_str); - kernel_param_lock(mk->mod); - if (ops->get) { - struct seq_buf s; - - seq_buf_init(&s, buf, PAGE_SIZE); - count = ops->get(&s, attribute->param); - if (count >= 0) { - WARN_ON_ONCE(count > 0); - count = seq_buf_used(&s); - /* Make sure string is terminated. */ - seq_buf_str(&s); - /* - * If overflowed, reduce count by 1 for trailing - * NUL byte. - */ - if (seq_buf_has_overflowed(&s)) - count--; - } - } else { - count = ops->get_str(buf, attribute->param); + seq_buf_init(&s, buf, PAGE_SIZE); + count = ops->get(&s, attribute->param); + if (count >= 0) { + WARN_ON_ONCE(count > 0); + count = seq_buf_used(&s); + /* Make sure string is terminated. */ + seq_buf_str(&s); + /* If overflowed, reduce count by 1 for trailing NUL byte. */ + if (seq_buf_has_overflowed(&s)) + count--; } kernel_param_unlock(mk->mod); return count; -- 2.34.1
