From ba3f5058db437d919f8468db50483dd9028ff688 Mon Sep 17 00:00:00 2001
From: Dmitry Antipov <dmantipov@yandex.ru>
Date: Tue, 28 Nov 2023 05:52:10 +0300
Subject: [PATCH] PNP: ACPI: fix fortify warning
Git-commit: ba3f5058db437d919f8468db50483dd9028ff688
Patch-mainline: v6.8-rc1
References: git-fixes

When compiling with gcc version 14.0.0 20231126 (experimental)
and CONFIG_FORTIFY_SOURCE=y, I've noticed the following:

In file included from ./include/linux/string.h:295,
                 from ./include/linux/bitmap.h:12,
                 from ./include/linux/cpumask.h:12,
                 from ./arch/x86/include/asm/paravirt.h:17,
                 from ./arch/x86/include/asm/cpuid.h:62,
                 from ./arch/x86/include/asm/processor.h:19,
                 from ./arch/x86/include/asm/cpufeature.h:5,
                 from ./arch/x86/include/asm/thread_info.h:53,
                 from ./include/linux/thread_info.h:60,
                 from ./arch/x86/include/asm/preempt.h:9,
                 from ./include/linux/preempt.h:79,
                 from ./include/linux/spinlock.h:56,
                 from ./include/linux/mmzone.h:8,
                 from ./include/linux/gfp.h:7,
                 from ./include/linux/slab.h:16,
                 from ./include/linux/resource_ext.h:11,
                 from ./include/linux/acpi.h:13,
                 from drivers/pnp/pnpacpi/rsparser.c:11:
In function 'fortify_memcpy_chk',
    inlined from 'pnpacpi_parse_allocated_vendor' at drivers/pnp/pnpacpi/rsparser.c:158:3,
    inlined from 'pnpacpi_allocated_resource' at drivers/pnp/pnpacpi/rsparser.c:249:3:
./include/linux/fortify-string.h:588:25: warning: call to '__read_overflow2_field'
declared with attribute warning: detected read beyond size of field (2nd parameter);
maybe use struct_group()? [-Wattribute-warning]
  588 |                         __read_overflow2_field(q_size_field, size);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

According to the comments in include/linux/fortify-string.h, 'memcpy()',
'memmove()' and 'memset()' must not be used beyond individual struct
members to ensure that the compiler can enforce protection against
buffer overflows, and, IIUC, this also applies to partial copies from
the particular member ('vendor->byte_data' in this case). So it should
be better (and safer) to do both copies at once (and 'byte_data' of
'struct acpi_resource_vendor_typed' seems to be a good candidate for
'__counted_by(byte_length)' as well).

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/pnp/pnpacpi/rsparser.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/pnp/pnpacpi/rsparser.c b/drivers/pnp/pnpacpi/rsparser.c
index 4f05f610391b..c02ce0834c2c 100644
--- a/drivers/pnp/pnpacpi/rsparser.c
+++ b/drivers/pnp/pnpacpi/rsparser.c
@@ -151,13 +151,13 @@ static int vendor_resource_matches(struct pnp_dev *dev,
 static void pnpacpi_parse_allocated_vendor(struct pnp_dev *dev,
 				    struct acpi_resource_vendor_typed *vendor)
 {
-	if (vendor_resource_matches(dev, vendor, &hp_ccsr_uuid, 16)) {
-		u64 start, length;
+	struct { u64 start, length; } range;
 
-		memcpy(&start, vendor->byte_data, sizeof(start));
-		memcpy(&length, vendor->byte_data + 8, sizeof(length));
-
-		pnp_add_mem_resource(dev, start, start + length - 1, 0);
+	if (vendor_resource_matches(dev, vendor, &hp_ccsr_uuid,
+				    sizeof(range))) {
+		memcpy(&range, vendor->byte_data, sizeof(range));
+		pnp_add_mem_resource(dev, range.start, range.start +
+				     range.length - 1, 0);
 	}
 }
 
-- 
2.35.3