Merge branch 'for-next/kspp' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git

4 files changed, 89 insertions, 20 deletions

diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index ededa32d6744..01bebcb33bd4 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -236,11 +236,11 @@ static ssize_t lkdtm_debugfs_entry(struct file *f,
 	if (count >= PAGE_SIZE)
 		return -EINVAL;
 
-	buf = (char *)__get_free_page(GFP_KERNEL);
+	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 	if (copy_from_user(buf, user_buf, count)) {
-		free_page((unsigned long) buf);
+		kfree(buf);
 		return -EFAULT;
 	}
 	/* NULL-terminate and remove enter */
@@ -248,7 +248,7 @@ static ssize_t lkdtm_debugfs_entry(struct file *f,
 	strim(buf);
 
 	crashtype = find_crashtype(buf);
-	free_page((unsigned long)buf);
+	kfree(buf);
 
 	if (!crashtype)
 		return -EINVAL;
@@ -271,7 +271,7 @@ static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 	ssize_t out;
 	char *buf;
 
-	buf = (char *)__get_free_page(GFP_KERNEL);
+	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (buf == NULL)
 		return -ENOMEM;
 
@@ -290,7 +290,7 @@ static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 
 	out = simple_read_from_buffer(user_buf, count, off,
 				      buf, n);
-	free_page((unsigned long) buf);
+	kfree(buf);
 
 	return out;
 }
@@ -313,11 +313,11 @@ static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 	if (count < 1)
 		return -EINVAL;
 
-	buf = (char *)__get_free_page(GFP_KERNEL);
+	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 	if (copy_from_user(buf, user_buf, count)) {
-		free_page((unsigned long) buf);
+		kfree(buf);
 		return -EFAULT;
 	}
 	/* NULL-terminate and remove enter */
@@ -325,7 +325,7 @@ static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 	strim(buf);
 
 	crashtype = find_crashtype(buf);
-	free_page((unsigned long) buf);
+	kfree(buf);
 	if (!crashtype)
 		return -EINVAL;
 
diff --git a/fs/signalfd.c b/fs/signalfd.c
index dff53745e352..22bc0870a824 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -48,17 +48,30 @@ static int signalfd_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
+static void refine_sigmask(struct signalfd_ctx *ctx, sigset_t *sigmask)
+{
+	struct k_sigaction *k = current->sighand->action;
+	int n;
+
+	*sigmask = ctx->sigmask;
+	for (n = 1; n <= _NSIG; ++n, ++k) {
+		if (k->sa.sa_flags & SA_IMMUTABLE)
+			sigaddset(sigmask, n);
+	}
+}
+
 static __poll_t signalfd_poll(struct file *file, poll_table *wait)
 {
 	struct signalfd_ctx *ctx = file->private_data;
 	__poll_t events = 0;
+	sigset_t sigmask;
 
 	poll_wait(file, &current->sighand->signalfd_wqh, wait);
 
 	spin_lock_irq(&current->sighand->siglock);
-	if (next_signal(&current->pending, &ctx->sigmask) ||
-	    next_signal(&current->signal->shared_pending,
-			&ctx->sigmask))
+	refine_sigmask(ctx, &sigmask);
+	if (next_signal(&current->pending, &sigmask) ||
+	    next_signal(&current->signal->shared_pending, &sigmask))
 		events |= EPOLLIN;
 	spin_unlock_irq(&current->sighand->siglock);
 
@@ -155,11 +168,13 @@ static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info
 				int nonblock)
 {
 	enum pid_type type;
-	ssize_t ret;
 	DECLARE_WAITQUEUE(wait, current);
+	sigset_t sigmask;
+	ssize_t ret;
 
 	spin_lock_irq(&current->sighand->siglock);
-	ret = dequeue_signal(&ctx->sigmask, info, &type);
+	refine_sigmask(ctx, &sigmask);
+	ret = dequeue_signal(&sigmask, info, &type);
 	switch (ret) {
 	case 0:
 		if (!nonblock)
@@ -174,7 +189,7 @@ static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info
 	add_wait_queue(&current->sighand->signalfd_wqh, &wait);
 	for (;;) {
 		set_current_state(TASK_INTERRUPTIBLE);
-		ret = dequeue_signal(&ctx->sigmask, info, &type);
+		ret = dequeue_signal(&sigmask, info, &type);
 		if (ret != 0)
 			break;
 		if (signal_pending(current)) {
@@ -184,6 +199,7 @@ static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info
 		spin_unlock_irq(&current->sighand->siglock);
 		schedule();
 		spin_lock_irq(&current->sighand->siglock);
+		refine_sigmask(ctx, &sigmask);
 	}
 	spin_unlock_irq(&current->sighand->siglock);
 
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
index cf841dc71fef..7e7c369e0a6c 100644
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h
@@ -458,10 +458,8 @@ __FORTIFY_INLINE bool fortify_memset_chk(__kernel_size_t size,
  * __struct_size() vs __member_size() must be captured here to avoid
  * evaluating argument side-effects further into the macro layers.
  */
-#ifndef CONFIG_KMSAN
 #define memset(p, c, s) __fortify_memset_chk(p, c, s,			\
 		__struct_size(p), __member_size(p))
-#endif
 
 /*
  * To make sure the compiler can enforce protection against buffer overflows,
diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index ff65a4f87f24..1e66f45fe29b 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -22,7 +22,7 @@
 #define ORIG_TYPE_NAME(node) \
 	(TYPE_NAME(TYPE_MAIN_VARIANT(node)) != NULL_TREE ? ((const unsigned char *)IDENTIFIER_POINTER(TYPE_NAME(TYPE_MAIN_VARIANT(node)))) : (const unsigned char *)"anonymous")
 
-#define INFORM(loc, msg, ...)	inform(loc, "randstruct: " msg, ##__VA_ARGS__)
+#define INFORM(loc, msg, ...)	warning_at(loc, 0, "randstruct: " msg, ##__VA_ARGS__)
 #define MISMATCH(loc, how, ...)	INFORM(loc, "casting between randomized structure pointer types (" how "): %qT and %qT\n", __VA_ARGS__)
 
 __visible int plugin_is_GPL_compatible;
@@ -699,6 +699,63 @@ static void handle_local_var_initializers(void)
 }
 
 /*
+ * Does @container reach a field of type @member_type by a chain of
+ * by-value members? That is the relationship container_of() expresses --
+ * its @member argument may be a dotted path, e.g.
+ * container_of(inode, struct ceph_inode_info, netfs.inode) -- so a cast
+ * from @member_type * to @container * is legitimate rather than a
+ * layout-confusing one.
+ *
+ * container_of() used to leave a "void *__mptr" temporary behind, and this
+ * pass recognised such casts by that name. Commit f9e7a7564834
+ * ("container_of: remove local __mptr variable") removed it to stop nested
+ * container_of() shadowing itself, and the cast now folds to a bare SSA
+ * copy when the member sits at offset 0, leaving nothing syntactic to key
+ * on. Match the type relationship instead.
+ *
+ * The depth bound keeps this cheap; container_of() paths are one or two
+ * members deep in practice.
+ */
+#define CONTAINER_OF_MAX_DEPTH 4
+
+static bool is_container_of_cast(const_tree container, const_tree member_type,
+				 int depth)
+{
+	const_tree field;
+
+	if (container == NULL_TREE || depth > CONTAINER_OF_MAX_DEPTH)
+		return false;
+
+	if (TREE_CODE(container) != RECORD_TYPE &&
+	    TREE_CODE(container) != UNION_TYPE)
+		return false;
+
+	for (field = TYPE_FIELDS(container); field; field = DECL_CHAIN(field)) {
+		const_tree field_type;
+
+		if (TREE_CODE(field) != FIELD_DECL)
+			continue;
+
+		/*
+		 * Only a member at offset 0 can reach here: for any other
+		 * offset container_of()'s subtraction survives folding, the
+		 * cast's rhs stays void *, and the caller skipped it above.
+		 */
+		if (!integer_zerop(byte_position(field)))
+			continue;
+
+		field_type = TYPE_MAIN_VARIANT(TREE_TYPE(field));
+		if (field_type == member_type)
+			return true;
+
+		if (is_container_of_cast(field_type, member_type, depth + 1))
+			return true;
+	}
+
+	return false;
+}
+
+/*
  * iterate over all statements to find "bad" casts:
  * those where the address of the start of a structure is cast
  * to a pointer of a structure of a different type, or a
@@ -799,10 +856,8 @@ static unsigned int find_bad_casts_execute(void)
 #endif
 				MISMATCH(gimple_location(stmt), "op0", ptr_lhs_type, op0_type);
 			} else {
-				const_tree ssa_name_var = SSA_NAME_VAR(rhs1);
 				/* skip bogus type casts introduced by container_of */
-				if (ssa_name_var != NULL_TREE && DECL_NAME(ssa_name_var) && 
-				    !strcmp((const char *)DECL_NAME_POINTER(ssa_name_var), "__mptr"))
+				if (is_container_of_cast(ptr_lhs_type, ptr_rhs_type, 0))
 					continue;
 #ifndef __DEBUG_PLUGIN
 				if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(ptr_rhs_type)))