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McKenney" , Peter Zijlstra , Thomas Gleixner , kernel-team@android.com, kernel-hardening@lists.openwall.com Subject: [RFC PATCH 14/21] plist: Use CHECK_DATA_CORRUPTION instead of explicit {BUG,WARN}_ON() Date: Tue, 24 Mar 2020 15:36:36 +0000 Message-Id: <20200324153643.15527-15-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200324153643.15527-1-will@kernel.org> References: <20200324153643.15527-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit CHECK_DATA_CORRUPTION() allows detected data corruption to result consistently in either a BUG() or a WARN() depending on CONFIG_BUG_ON_DATA_CORRUPTION. Use CHECK_DATA_CORRUPTION() to report plist integrity checking failures, rather than explicit use of BUG_ON() and WARN_ON(). Cc: Kees Cook Cc: Paul E. McKenney Cc: Peter Zijlstra Signed-off-by: Will Deacon --- lib/plist.c | 63 ++++++++++++++++++++++++++++++++++------------------- 1 file changed, 40 insertions(+), 23 deletions(-) diff --git a/lib/plist.c b/lib/plist.c index c06e98e78259..eb127eaab235 100644 --- a/lib/plist.c +++ b/lib/plist.c @@ -29,39 +29,46 @@ static struct plist_head test_head; -static void plist_check_prev_next(struct list_head *t, struct list_head *p, - struct list_head *n) +static bool plist_prev_next_invalid(struct list_head *t, struct list_head *p, + struct list_head *n) { - WARN(n->prev != p || p->next != n, - "top: %p, n: %p, p: %p\n" - "prev: %p, n: %p, p: %p\n" - "next: %p, n: %p, p: %p\n", + return CHECK_DATA_CORRUPTION(n->prev != p || p->next != n, + "plist corruption:\n" + "\ttop: %p, n: %p, p: %p\n" + "\tprev: %p, n: %p, p: %p\n" + "\tnext: %p, n: %p, p: %p\n", t, t->next, t->prev, p, p->next, p->prev, n, n->next, n->prev); } -static void plist_check_list(struct list_head *top) +static bool plist_list_invalid(struct list_head *top) { struct list_head *prev = top, *next = top->next; + bool corruption; - plist_check_prev_next(top, prev, next); + corruption = plist_prev_next_invalid(top, prev, next); while (next != top) { prev = next; next = prev->next; - plist_check_prev_next(top, prev, next); + corruption |= plist_prev_next_invalid(top, prev, next); } + + return corruption; } -static void plist_check_head(struct plist_head *head) +static bool plist_head_valid(struct plist_head *head) { + bool corruption = false; + if (!plist_head_empty(head)) - plist_check_list(&plist_first(head)->prio_list); - plist_check_list(&head->node_list); + corruption |= plist_list_invalid(&plist_first(head)->prio_list); + corruption |= plist_list_invalid(&head->node_list); + return !corruption; } #else -# define plist_check_head(h) do { } while (0) +# define plist_head_valid(h) (true) #endif /** @@ -75,9 +82,12 @@ void plist_add(struct plist_node *node, struct plist_head *head) struct plist_node *first, *iter, *prev = NULL; struct list_head *node_next = &head->node_list; - plist_check_head(head); - WARN_ON(!plist_node_empty(node)); - WARN_ON(!list_empty(&node->prio_list)); + if (!plist_head_valid(head) || + CHECK_DATA_CORRUPTION(!plist_node_empty(node), + "plist_add corruption. node list is not empty.\n") || + CHECK_DATA_CORRUPTION(!list_empty(&node->prio_list), + "plist_add corruption. node prio list is not empty.\n")) + return; if (plist_head_empty(head)) goto ins_node; @@ -100,7 +110,8 @@ void plist_add(struct plist_node *node, struct plist_head *head) ins_node: list_add_tail(&node->node_list, node_next); - plist_check_head(head); + if (!plist_head_valid(head)) + return; } /** @@ -111,7 +122,8 @@ void plist_add(struct plist_node *node, struct plist_head *head) */ void plist_del(struct plist_node *node, struct plist_head *head) { - plist_check_head(head); + if (!plist_head_valid(head)) + return; if (!list_empty(&node->prio_list)) { if (node->node_list.next != &head->node_list) { @@ -129,7 +141,8 @@ void plist_del(struct plist_node *node, struct plist_head *head) list_del_init(&node->node_list); - plist_check_head(head); + if (!plist_head_valid(head)) + return; } /** @@ -147,9 +160,12 @@ void plist_requeue(struct plist_node *node, struct plist_head *head) struct plist_node *iter; struct list_head *node_next = &head->node_list; - plist_check_head(head); - BUG_ON(plist_head_empty(head)); - BUG_ON(plist_node_empty(node)); + if (!plist_head_valid(head) || + CHECK_DATA_CORRUPTION(plist_head_empty(head), + "plist_requeue corruption. head list is empty.\n") || + CHECK_DATA_CORRUPTION(plist_node_empty(node), + "plist_requeue corruption. node list is empty.\n")) + return; if (node == plist_last(head)) return; @@ -169,7 +185,8 @@ void plist_requeue(struct plist_node *node, struct plist_head *head) } list_add_tail(&node->node_list, node_next); - plist_check_head(head); + if (!plist_head_valid(head)) + return; } #ifdef CONFIG_CHECK_INTEGRITY_PLIST -- 2.20.1