[PATCH 5.15 620/779] s390/maccess: fix semantics of memcpy_real() and its callers

From: Greg Kroah-Hartman
Date: Mon Aug 15 2022 - 15:38:45 EST

From: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>

[ Upstream commit 303fd988ed644c7daa260410f3ac99266573557d ]

There is a confusion with regard to the source address of
memcpy_real() and calling functions. While the declared
type for a source assumes a virtual address, in fact it
always called with physical address of the source.

This confusion led to bugs in copy_oldmem_kernel() and
copy_oldmem_user() functions, where __pa() macro applied
mistakenly to physical addresses. It does not lead to a
real issue, since virtual and physical addresses are
currently the same.

Fix both the bugs and memcpy_real() prototype by making
type of source address consistent to the function name
and the way it actually used.

Reviewed-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/s390/include/asm/os_info.h | 2 +-
arch/s390/include/asm/processor.h | 2 +-
arch/s390/include/asm/uaccess.h | 2 +-
arch/s390/kernel/crash_dump.c | 58 +++++++++++++++----------------
arch/s390/kernel/os_info.c | 7 ++--
arch/s390/kernel/smp.c | 2 +-
arch/s390/mm/maccess.c | 4 +--
drivers/s390/char/zcore.c | 3 +-
8 files changed, 38 insertions(+), 42 deletions(-)

diff --git a/arch/s390/include/asm/os_info.h b/arch/s390/include/asm/os_info.h
index 3c89279d2a4b..147a8d547ef9 100644
--- a/arch/s390/include/asm/os_info.h
+++ b/arch/s390/include/asm/os_info.h
@@ -39,7 +39,7 @@ u32 os_info_csum(struct os_info *os_info);

#ifdef CONFIG_CRASH_DUMP
void *os_info_old_entry(int nr, unsigned long *size);
-int copy_oldmem_kernel(void *dst, void *src, size_t count);
+int copy_oldmem_kernel(void *dst, unsigned long src, size_t count);
#else
static inline void *os_info_old_entry(int nr, unsigned long *size)
{
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 879b8e3f609c..e9db8efd50f2 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -318,7 +318,7 @@ extern void (*s390_base_pgm_handler_fn)(void);

#define ARCH_LOW_ADDRESS_LIMIT 0x7fffffffUL

-extern int memcpy_real(void *, void *, size_t);
+extern int memcpy_real(void *, unsigned long, size_t);
extern void memcpy_absolute(void *, void *, size_t);

#define mem_assign_absolute(dest, val) do { \
diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index ce550d06abc3..3379694e9a42 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -245,7 +245,7 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo
return __clear_user(to, n);
}

-int copy_to_user_real(void __user *dest, void *src, unsigned long count);
+int copy_to_user_real(void __user *dest, unsigned long src, unsigned long count);
void *s390_kernel_write(void *dst, const void *src, size_t size);

#define HAVE_GET_KERNEL_NOFAULT
diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 9c2597be28dc..199f136d1644 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -132,28 +132,27 @@ static inline void *load_real_addr(void *addr)
/*
* Copy memory of the old, dumped system to a kernel space virtual address
*/
-int copy_oldmem_kernel(void *dst, void *src, size_t count)
+int copy_oldmem_kernel(void *dst, unsigned long src, size_t count)
{
- unsigned long from, len;
+ unsigned long len;
void *ra;
int rc;

while (count) {
- from = __pa(src);
- if (!oldmem_data.start && from < sclp.hsa_size) {
+ if (!oldmem_data.start && src < sclp.hsa_size) {
/* Copy from zfcp/nvme dump HSA area */
- len = min(count, sclp.hsa_size - from);
- rc = memcpy_hsa_kernel(dst, from, len);
+ len = min(count, sclp.hsa_size - src);
+ rc = memcpy_hsa_kernel(dst, src, len);
if (rc)
return rc;
} else {
/* Check for swapped kdump oldmem areas */
- if (oldmem_data.start && from - oldmem_data.start < oldmem_data.size) {
- from -= oldmem_data.start;
- len = min(count, oldmem_data.size - from);
- } else if (oldmem_data.start && from < oldmem_data.size) {
- len = min(count, oldmem_data.size - from);
- from += oldmem_data.start;
+ if (oldmem_data.start && src - oldmem_data.start < oldmem_data.size) {
+ src -= oldmem_data.start;
+ len = min(count, oldmem_data.size - src);
+ } else if (oldmem_data.start && src < oldmem_data.size) {
+ len = min(count, oldmem_data.size - src);
+ src += oldmem_data.start;
} else {
len = count;
}
@@ -163,7 +162,7 @@ int copy_oldmem_kernel(void *dst, void *src, size_t count)
} else {
ra = dst;
}
- if (memcpy_real(ra, (void *) from, len))
+ if (memcpy_real(ra, src, len))
return -EFAULT;
}
dst += len;
@@ -176,31 +175,30 @@ int copy_oldmem_kernel(void *dst, void *src, size_t count)
/*
* Copy memory of the old, dumped system to a user space virtual address
*/
-static int copy_oldmem_user(void __user *dst, void *src, size_t count)
+static int copy_oldmem_user(void __user *dst, unsigned long src, size_t count)
{
- unsigned long from, len;
+ unsigned long len;
int rc;

while (count) {
- from = __pa(src);
- if (!oldmem_data.start && from < sclp.hsa_size) {
+ if (!oldmem_data.start && src < sclp.hsa_size) {
/* Copy from zfcp/nvme dump HSA area */
- len = min(count, sclp.hsa_size - from);
- rc = memcpy_hsa_user(dst, from, len);
+ len = min(count, sclp.hsa_size - src);
+ rc = memcpy_hsa_user(dst, src, len);
if (rc)
return rc;
} else {
/* Check for swapped kdump oldmem areas */
- if (oldmem_data.start && from - oldmem_data.start < oldmem_data.size) {
- from -= oldmem_data.start;
- len = min(count, oldmem_data.size - from);
- } else if (oldmem_data.start && from < oldmem_data.size) {
- len = min(count, oldmem_data.size - from);
- from += oldmem_data.start;
+ if (oldmem_data.start && src - oldmem_data.start < oldmem_data.size) {
+ src -= oldmem_data.start;
+ len = min(count, oldmem_data.size - src);
+ } else if (oldmem_data.start && src < oldmem_data.size) {
+ len = min(count, oldmem_data.size - src);
+ src += oldmem_data.start;
} else {
len = count;
}
- rc = copy_to_user_real(dst, (void *) from, count);
+ rc = copy_to_user_real(dst, src, count);
if (rc)
return rc;
}
@@ -217,12 +215,12 @@ static int copy_oldmem_user(void __user *dst, void *src, size_t count)
ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
unsigned long offset, int userbuf)
{
- void *src;
+ unsigned long src;
int rc;

if (!csize)
return 0;
- src = (void *) (pfn << PAGE_SHIFT) + offset;
+ src = pfn_to_phys(pfn) + offset;
if (userbuf)
rc = copy_oldmem_user((void __force __user *) buf, src, csize);
else
@@ -429,10 +427,10 @@ static void *nt_prpsinfo(void *ptr)
static void *get_vmcoreinfo_old(unsigned long *size)
{
char nt_name[11], *vmcoreinfo;
+ unsigned long addr;
Elf64_Nhdr note;
- void *addr;

- if (copy_oldmem_kernel(&addr, (void *)__LC_VMCORE_INFO, sizeof(addr)))
+ if (copy_oldmem_kernel(&addr, __LC_VMCORE_INFO, sizeof(addr)))
return NULL;
memset(nt_name, 0, sizeof(nt_name));
if (copy_oldmem_kernel(&note, addr, sizeof(note)))
diff --git a/arch/s390/kernel/os_info.c b/arch/s390/kernel/os_info.c
index 198f9694e439..e548844dde28 100644
--- a/arch/s390/kernel/os_info.c
+++ b/arch/s390/kernel/os_info.c
@@ -91,7 +91,7 @@ static void os_info_old_alloc(int nr, int align)
goto fail;
}
buf_align = PTR_ALIGN(buf, align);
- if (copy_oldmem_kernel(buf_align, (void *) addr, size)) {
+ if (copy_oldmem_kernel(buf_align, addr, size)) {
msg = "copy failed";
goto fail_free;
}
@@ -124,15 +124,14 @@ static void os_info_old_init(void)
return;
if (!oldmem_data.start)
goto fail;
- if (copy_oldmem_kernel(&addr, (void *)__LC_OS_INFO, sizeof(addr)))
+ if (copy_oldmem_kernel(&addr, __LC_OS_INFO, sizeof(addr)))
goto fail;
if (addr == 0 || addr % PAGE_SIZE)
goto fail;
os_info_old = kzalloc(sizeof(*os_info_old), GFP_KERNEL);
if (!os_info_old)
goto fail;
- if (copy_oldmem_kernel(os_info_old, (void *) addr,
- sizeof(*os_info_old)))
+ if (copy_oldmem_kernel(os_info_old, addr, sizeof(*os_info_old)))
goto fail_free;
if (os_info_old->magic != OS_INFO_MAGIC)
goto fail_free;
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 1a04e5bdf655..e57eb2260b90 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -675,7 +675,7 @@ static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
void *regs = (void *) page;

if (is_boot_cpu)
- copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
+ copy_oldmem_kernel(regs, __LC_FPREGS_SAVE_AREA, 512);
else
__pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
save_area_add_regs(sa, regs);
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 9663ce3625bc..2ed198b4f7d0 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -123,7 +123,7 @@ static unsigned long __no_sanitize_address _memcpy_real(unsigned long dest,
/*
* Copy memory in real mode (kernel to kernel)
*/
-int memcpy_real(void *dest, void *src, size_t count)
+int memcpy_real(void *dest, unsigned long src, size_t count)
{
unsigned long _dest = (unsigned long)dest;
unsigned long _src = (unsigned long)src;
@@ -175,7 +175,7 @@ void memcpy_absolute(void *dest, void *src, size_t count)
/*
* Copy memory from kernel (real) to user (virtual)
*/
-int copy_to_user_real(void __user *dest, void *src, unsigned long count)
+int copy_to_user_real(void __user *dest, unsigned long src, unsigned long count)
{
int offs = 0, size, rc;
char *buf;
diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
index 3ba2d934a3e8..516783ba950f 100644
--- a/drivers/s390/char/zcore.c
+++ b/drivers/s390/char/zcore.c
@@ -229,8 +229,7 @@ static int __init zcore_reipl_init(void)
rc = memcpy_hsa_kernel(zcore_ipl_block, ipib_info.ipib,
PAGE_SIZE);
else
- rc = memcpy_real(zcore_ipl_block, (void *) ipib_info.ipib,
- PAGE_SIZE);
+ rc = memcpy_real(zcore_ipl_block, ipib_info.ipib, PAGE_SIZE);
if (rc || (__force u32)csum_partial(zcore_ipl_block, zcore_ipl_block->hdr.len, 0) !=
ipib_info.checksum) {
TRACE("Checksum does not match\n");
--
2.35.1