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authorKees Cook <keescook@chromium.org>2016-08-18 00:42:08 +0300
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-10-31 23:01:56 +0300
commitd7c816733d501b59dbdc2483f2cc8e4431fd9160 (patch)
tree2b612eb24d1a506dc4cf4a5a519fb53e382b8bc0 /include/linux/list.h
parent1001354ca34179f3db924eb66672442a173147dc (diff)
downloadlinux-d7c816733d501b59dbdc2483f2cc8e4431fd9160.tar.xz
list: Split list_add() debug checking into separate function
Right now, __list_add() code is repeated either in list.h or in list_debug.c, but the only differences between the two versions are the debug checks. This commit therefore extracts these debug checks into a separate __list_add_valid() function and consolidates __list_add(). Additionally this new __list_add_valid() function will stop list manipulations if a corruption is detected, instead of allowing for further corruption that may lead to even worse conditions. This is slight refactoring of the same hardening done in PaX and Grsecurity. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Rik van Riel <riel@redhat.com>
Diffstat (limited to 'include/linux/list.h')
-rw-r--r--include/linux/list.h22
1 files changed, 16 insertions, 6 deletions
diff --git a/include/linux/list.h b/include/linux/list.h
index 5809e9a2de5b..b6da9b1dce4d 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -28,27 +28,37 @@ static inline void INIT_LIST_HEAD(struct list_head *list)
list->prev = list;
}
+#ifdef CONFIG_DEBUG_LIST
+extern bool __list_add_valid(struct list_head *new,
+ struct list_head *prev,
+ struct list_head *next);
+#else
+static inline bool __list_add_valid(struct list_head *new,
+ struct list_head *prev,
+ struct list_head *next)
+{
+ return true;
+}
+#endif
+
/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
-#ifndef CONFIG_DEBUG_LIST
static inline void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next)
{
+ if (!__list_add_valid(new, prev, next))
+ return;
+
next->prev = new;
new->next = next;
new->prev = prev;
WRITE_ONCE(prev->next, new);
}
-#else
-extern void __list_add(struct list_head *new,
- struct list_head *prev,
- struct list_head *next);
-#endif
/**
* list_add - add a new entry