[PATCH AUTOSEL 6.0 11/44] s390/zcrypt: fix warning about field-spanning write

[PATCH AUTOSEL 6.0 11/44] s390/zcrypt: fix warning about field-spanning write

[Sasha Levin]

From: Harald Freudenberger <freude@linux.ibm.com>

[ Upstream commit b43088f30db1a7bff61c8486238c195c77788d6d ]

This patch fixes the warning

memcpy: detected field-spanning write (size 60) of single field "to" at drivers/s390/crypto/zcrypt_api.h:173 (size 2)
WARNING: CPU: 1 PID: 2114 at drivers/s390/crypto/zcrypt_api.h:173 prep_ep11_ap_msg+0x2c6/0x2e0 [zcrypt]

The code has been rewritten to use a union in combination
with a flex array to clearly state which part of the buffer
the payload is to be copied in via z_copy_from_user
function (which may call memcpy() in case of in-kernel calls).

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Suggested-by: Jürgen Christ <jchrist@linux.ibm.com>
Reviewed-by: Jürgen Christ <jchrist@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/s390/crypto/zcrypt_msgtype6.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/s390/crypto/zcrypt_msgtype6.c b/drivers/s390/crypto/zcrypt_msgtype6.c
index 8fb34b8eeb18..5ad251477593 100644
--- a/drivers/s390/crypto/zcrypt_msgtype6.c
+++ b/drivers/s390/crypto/zcrypt_msgtype6.c
@@ -342,7 +342,10 @@ static int xcrb_msg_to_type6cprb_msgx(bool userspace, struct ap_message *ap_msg,
 	};
 	struct {
 		struct type6_hdr hdr;
-		struct CPRBX cprbx;
+		union {
+			struct CPRBX cprbx;
+			DECLARE_FLEX_ARRAY(u8, userdata);
+		};
 	} __packed * msg = ap_msg->msg;
 
 	int rcblen = CEIL4(xcrb->request_control_blk_length);
@@ -403,7 +406,8 @@ static int xcrb_msg_to_type6cprb_msgx(bool userspace, struct ap_message *ap_msg,
 	msg->hdr.fromcardlen2 = xcrb->reply_data_length;
 
 	/* prepare CPRB */
-	if (z_copy_from_user(userspace, &msg->cprbx, xcrb->request_control_blk_addr,
+	if (z_copy_from_user(userspace, msg->userdata,
+			     xcrb->request_control_blk_addr,
 			     xcrb->request_control_blk_length))
 		return -EFAULT;
 	if (msg->cprbx.cprb_len + sizeof(msg->hdr.function_code) >
@@ -469,9 +473,14 @@ static int xcrb_msg_to_type6_ep11cprb_msgx(bool userspace, struct ap_message *ap
 
 	struct {
 		struct type6_hdr hdr;
-		struct ep11_cprb cprbx;
-		unsigned char	pld_tag;	/* fixed value 0x30 */
-		unsigned char	pld_lenfmt;	/* payload length format */
+		union {
+			struct {
+				struct ep11_cprb cprbx;
+				unsigned char pld_tag;    /* fixed value 0x30 */
+				unsigned char pld_lenfmt; /* length format */
+			} __packed;
+			DECLARE_FLEX_ARRAY(u8, userdata);
+		};
 	} __packed * msg = ap_msg->msg;
 
 	struct pld_hdr {
@@ -500,7 +509,7 @@ static int xcrb_msg_to_type6_ep11cprb_msgx(bool userspace, struct ap_message *ap
 	msg->hdr.fromcardlen1 = xcrb->resp_len;
 
 	/* Import CPRB data from the ioctl input parameter */
-	if (z_copy_from_user(userspace, &msg->cprbx.cprb_len,
+	if (z_copy_from_user(userspace, msg->userdata,
 			     (char __force __user *)xcrb->req, xcrb->req_len)) {
 		return -EFAULT;
 	}
-- 
2.35.1

[PATCH AUTOSEL 6.0 29/44] s390: always build relocatable kernel

[Sasha Levin]

From: Heiko Carstens <hca@linux.ibm.com>

[ Upstream commit 80ddf5ce1c9291cb175d52ed1227134ad48c47ee ]

Nathan Chancellor reported several link errors on s390 with
CONFIG_RELOCATABLE disabled, after binutils commit 906f69cf65da ("IBM
zSystems: Issue error for *DBL relocs on misaligned symbols"). The binutils
commit reveals potential miscompiles that might have happened already
before with linker script defined symbols at odd addresses.

A similar bug was recently fixed in the kernel with commit c9305b6c1f52
("s390: fix nospec table alignments").

See https://github.com/ClangBuiltLinux/linux/issues/1747 for an analysis
from Ulich Weigand.

Therefore always build a relocatable kernel to avoid this problem. There is
hardly any use-case for non-relocatable kernels, so this shouldn't be
controversial.

Link: https://github.com/ClangBuiltLinux/linux/issues/1747
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20221030182202.2062705-1-hca@linux.ibm.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/Kconfig        | 6 +++---
 arch/s390/Makefile       | 2 --
 arch/s390/boot/Makefile  | 3 +--
 arch/s390/boot/startup.c | 3 +--
 4 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 318fce77601d..de575af02ffe 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -568,8 +568,7 @@ config EXPOLINE_FULL
 endchoice
 
 config RELOCATABLE
-	bool "Build a relocatable kernel"
-	default y
+	def_bool y
 	help
 	  This builds a kernel image that retains relocation information
 	  so it can be loaded at an arbitrary address.
@@ -578,10 +577,11 @@ config RELOCATABLE
 	  bootup process.
 	  The relocations make the kernel image about 15% larger (compressed
 	  10%), but are discarded at runtime.
+	  Note: this option exists only for documentation purposes, please do
+	  not remove it.
 
 config RANDOMIZE_BASE
 	bool "Randomize the address of the kernel image (KASLR)"
-	depends on RELOCATABLE
 	default y
 	help
 	  In support of Kernel Address Space Layout Randomization (KASLR),
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 4cb5d17e7ead..47bec926d6c0 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -14,10 +14,8 @@ KBUILD_AFLAGS_MODULE += -fPIC
 KBUILD_CFLAGS_MODULE += -fPIC
 KBUILD_AFLAGS	+= -m64
 KBUILD_CFLAGS	+= -m64
-ifeq ($(CONFIG_RELOCATABLE),y)
 KBUILD_CFLAGS	+= -fPIE
 LDFLAGS_vmlinux	:= -pie
-endif
 aflags_dwarf	:= -Wa,-gdwarf-2
 KBUILD_AFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -D__ASSEMBLY__
 ifndef CONFIG_AS_IS_LLVM
diff --git a/arch/s390/boot/Makefile b/arch/s390/boot/Makefile
index 883357a211a3..d52c3e2e16bc 100644
--- a/arch/s390/boot/Makefile
+++ b/arch/s390/boot/Makefile
@@ -37,9 +37,8 @@ CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char
 
 obj-y	:= head.o als.o startup.o mem_detect.o ipl_parm.o ipl_report.o
 obj-y	+= string.o ebcdic.o sclp_early_core.o mem.o ipl_vmparm.o cmdline.o
-obj-y	+= version.o pgm_check_info.o ctype.o ipl_data.o
+obj-y	+= version.o pgm_check_info.o ctype.o ipl_data.o machine_kexec_reloc.o
 obj-$(findstring y, $(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) $(CONFIG_PGSTE))	+= uv.o
-obj-$(CONFIG_RELOCATABLE)	+= machine_kexec_reloc.o
 obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr.o
 obj-y	+= $(if $(CONFIG_KERNEL_UNCOMPRESSED),,decompressor.o) info.o
 obj-$(CONFIG_KERNEL_ZSTD) += clz_ctz.o
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index bc48fe82d949..e5026e1d277f 100644
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c
@@ -285,8 +285,7 @@ void startup_kernel(void)
 
 	clear_bss_section();
 	copy_bootdata();
-	if (IS_ENABLED(CONFIG_RELOCATABLE))
-		handle_relocs(__kaslr_offset);
+	handle_relocs(__kaslr_offset);
 
 	if (__kaslr_offset) {
 		/*
-- 
2.35.1