From 0cd340dcb05c4a43742fe156f36737bb2a321bfd Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 17 Aug 2016 14:42:10 -0700 Subject: list: Split list_del() debug checking into separate function Similar to the list_add() debug consolidation, this commit consolidates the debug checking performed during CONFIG_DEBUG_LIST into a new __list_del_entry_valid() function, and stops list updates when corruption is found. Refactored from same hardening in PaX and Grsecurity. Signed-off-by: Kees Cook Acked-by: Steven Rostedt Signed-off-by: Paul E. McKenney Acked-by: Rik van Riel --- include/linux/list.h | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'include/linux/list.h') diff --git a/include/linux/list.h b/include/linux/list.h index b6da9b1dce4d..d1039ecaf94f 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -32,6 +32,7 @@ static inline void INIT_LIST_HEAD(struct list_head *list) extern bool __list_add_valid(struct list_head *new, struct list_head *prev, struct list_head *next); +extern bool __list_del_entry_valid(struct list_head *entry); #else static inline bool __list_add_valid(struct list_head *new, struct list_head *prev, @@ -39,6 +40,10 @@ static inline bool __list_add_valid(struct list_head *new, { return true; } +static inline bool __list_del_entry_valid(struct list_head *entry) +{ + return true; +} #endif /* @@ -106,22 +111,20 @@ static inline void __list_del(struct list_head * prev, struct list_head * next) * Note: list_empty() on entry does not return true after this, the entry is * in an undefined state. */ -#ifndef CONFIG_DEBUG_LIST static inline void __list_del_entry(struct list_head *entry) { + if (!__list_del_entry_valid(entry)) + return; + __list_del(entry->prev, entry->next); } static inline void list_del(struct list_head *entry) { - __list_del(entry->prev, entry->next); + __list_del_entry(entry); entry->next = LIST_POISON1; entry->prev = LIST_POISON2; } -#else -extern void __list_del_entry(struct list_head *entry); -extern void list_del(struct list_head *entry); -#endif /** * list_replace - replace old entry by new one -- cgit v1.2.3