treewide: refresh kmalloc_obj() conversionsgrafted

This is another run of the Coccinelle script for converting kmalloc()
family of allocations to kmalloc_obj() via the existing rules in
scripts/coccinelle/api/kmalloc_objs.cocci

This catches both the set of kmalloc() uses added since the first
kmalloc_obj() conversions in v7.0 and adds a large group missed in the
first pass due to Coccinelle not interacting well with the cleanup.h
scoped_...() family of macros[1]. I worked around this with spatch's
"--macro-file" argument to a file with all the scoped_...() macros mapped
to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control
flow indicator I could find.

Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc,
riscv, and s390 with no new warnings.

Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1]
Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2]
Signed-off-by: Kees Cook <kees+treewide@kernel.org>

1 files changed, 55 insertions, 0 deletions

diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
new file mode 100644
index 000000000..24b48af27
--- /dev/null
+++ b/arch/x86/lib/usercopy.c
@@ -0,0 +1,55 @@
+/*
+ * User address space access functions.
+ *
+ *  For licencing details see kernel-base/COPYING
+ */
+
+#include <linux/uaccess.h>
+#include <linux/export.h>
+#include <linux/instrumented.h>
+
+#include <asm/tlbflush.h>
+
+/**
+ * copy_from_user_nmi - NMI safe copy from user
+ * @to:		Pointer to the destination buffer
+ * @from:	Pointer to a user space address of the current task
+ * @n:		Number of bytes to copy
+ *
+ * Returns: The number of not copied bytes. 0 is success, i.e. all bytes copied
+ *
+ * Contrary to other copy_from_user() variants this function can be called
+ * from NMI context. Despite the name it is not restricted to be called
+ * from NMI context. It is safe to be called from any other context as
+ * well. It disables pagefaults across the copy which means a fault will
+ * abort the copy.
+ *
+ * For NMI context invocations this relies on the nested NMI work to allow
+ * atomic faults from the NMI path; the nested NMI paths are careful to
+ * preserve CR2.
+ */
+unsigned long
+copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
+{
+	unsigned long ret;
+
+	if (!__access_ok(from, n))
+		return n;
+
+	if (!nmi_uaccess_okay())
+		return n;
+
+	/*
+	 * Even though this function is typically called from NMI/IRQ context
+	 * disable pagefaults so that its behaviour is consistent even when
+	 * called from other contexts.
+	 */
+	pagefault_disable();
+	instrument_copy_from_user_before(to, from, n);
+	ret = raw_copy_from_user(to, from, n);
+	instrument_copy_from_user_after(to, from, n, ret);
+	pagefault_enable();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(copy_from_user_nmi);