3 files changed, 29 insertions, 5 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 05452c3b9872..9df3f4839662 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2817,7 +2817,7 @@ static int proc_##LSM##_attr_dir_iterate(struct file *filp, \
 \
 static const struct file_operations proc_##LSM##_attr_dir_ops = { \
 	.read		= generic_read_dir, \
-	.iterate	= proc_##LSM##_attr_dir_iterate, \
+	.iterate_shared	= proc_##LSM##_attr_dir_iterate, \
 	.llseek		= default_llseek, \
 }; \
 \
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 9cb32e1a78a0..23fc24d16b31 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -309,6 +309,8 @@ static void append_kcore_note(char *notes, size_t *i, const char *name,
 
 static ssize_t read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
+	struct file *file = iocb->ki_filp;
+	char *buf = file->private_data;
 	loff_t *fpos = &iocb->ki_pos;
 	size_t phdrs_offset, notes_offset, data_offset;
 	size_t page_offline_frozen = 1;
@@ -555,10 +557,21 @@ static ssize_t read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
 		case KCORE_VMEMMAP:
 		case KCORE_TEXT:
 			/*
-			 * We use _copy_to_iter() to bypass usermode hardening
-			 * which would otherwise prevent this operation.
+			 * Sadly we must use a bounce buffer here to be able to
+			 * make use of copy_from_kernel_nofault(), as these
+			 * memory regions might not always be mapped on all
+			 * architectures.
 			 */
-			if (_copy_to_iter((char *)start, tsz, iter) != tsz) {
+			if (copy_from_kernel_nofault(buf, (void *)start, tsz)) {
+				if (iov_iter_zero(tsz, iter) != tsz) {
+					ret = -EFAULT;
+					goto out;
+				}
+			/*
+			 * We know the bounce buffer is safe to copy from, so
+			 * use _copy_to_iter() directly.
+			 */
+			} else if (_copy_to_iter(buf, tsz, iter) != tsz) {
 				ret = -EFAULT;
 				goto out;
 			}
@@ -595,6 +608,10 @@ static int open_kcore(struct inode *inode, struct file *filp)
 	if (ret)
 		return ret;
 
+	filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!filp->private_data)
+		return -ENOMEM;
+
 	if (kcore_need_update)
 		kcore_update_ram();
 	if (i_size_read(inode) != proc_root_kcore->size) {
@@ -605,9 +622,16 @@ static int open_kcore(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+static int release_kcore(struct inode *inode, struct file *file)
+{
+	kfree(file->private_data);
+	return 0;
+}
+
 static const struct proc_ops kcore_proc_ops = {
 	.proc_read_iter	= read_kcore_iter,
 	.proc_open	= open_kcore,
+	.proc_release	= release_kcore,
 	.proc_lseek	= default_llseek,
 };
 
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index cb80a7703d58..1fb213f379a5 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -132,7 +132,7 @@ ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
 			 u64 *ppos, bool encrypted)
 {
 	unsigned long pfn, offset;
-	size_t nr_bytes;
+	ssize_t nr_bytes;
 	ssize_t read = 0, tmp;
 	int idx;