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Subject[PATCH 1/2] x86: Check return values from early_memremap calls
Date
There are a number of places where early_memremap is called
but the return pointer is not checked for NULL. The call
can result in a NULL being returned so the checks must
be added.

Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
---
arch/x86/kernel/devicetree.c | 10 ++++++++++
arch/x86/kernel/e820.c | 5 +++++
arch/x86/kernel/jailhouse.c | 6 ++++++
arch/x86/kernel/mpparse.c | 23 +++++++++++++++++++++++
arch/x86/kernel/setup.c | 5 +++++
arch/x86/xen/enlighten_hvm.c | 2 ++
arch/x86/xen/mmu_pv.c | 8 ++++++++
arch/x86/xen/setup.c | 2 ++
8 files changed, 61 insertions(+)

diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index 5cd51f2..ca23875 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -292,10 +292,20 @@ static void __init x86_flattree_get_config(void)
map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK), (u64)128);

dt = early_memremap(initial_dtb, map_len);
+ if (!dt) {
+ pr_warn("devicetree: failed to memremap initial dtb\n");
+ return;
+ }
+
size = fdt_totalsize(dt);
if (map_len < size) {
early_memunmap(dt, map_len);
dt = early_memremap(initial_dtb, size);
+ if (!dt) {
+ pr_warn("devicetree: failed to memremap initial dtb\n");
+ return;
+ }
+
map_len = size;
}

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index f267205..f90b883 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -728,6 +728,11 @@ void __init e820__memory_setup_extended(u64 phys_addr, u32 data_len)
struct setup_data *sdata;

sdata = early_memremap(phys_addr, data_len);
+ if (!sdata) {
+ pr_warn("e820: failed to memremap extended\n");
+ return;
+ }
+
entries = sdata->len / sizeof(*extmap);
extmap = (struct boot_e820_entry *)(sdata->data);

diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c
index 4eb8f2d..80db0c2 100644
--- a/arch/x86/kernel/jailhouse.c
+++ b/arch/x86/kernel/jailhouse.c
@@ -221,6 +221,9 @@ static void __init jailhouse_init_platform(void)

while (pa_data) {
mapping = early_memremap(pa_data, sizeof(header));
+ if (!mapping)
+ panic("Jailhouse: failed to memremap setup_data header\n");
+
memcpy(&header, mapping, sizeof(header));
early_memunmap(mapping, sizeof(header));

@@ -241,6 +244,9 @@ static void __init jailhouse_init_platform(void)
setup_data_len = min_t(unsigned long, sizeof(setup_data),
(unsigned long)header.len);
mapping = early_memremap(pa_data, setup_data_len);
+ if (!mapping)
+ panic("Jailhouse: failed to memremap setup_data\n");
+
memcpy(&setup_data, mapping, setup_data_len);
early_memunmap(mapping, setup_data_len);

diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
index fed721f..8bac042 100644
--- a/arch/x86/kernel/mpparse.c
+++ b/arch/x86/kernel/mpparse.c
@@ -424,6 +424,9 @@ static unsigned long __init get_mpc_size(unsigned long physptr)
unsigned long size;

mpc = early_memremap(physptr, PAGE_SIZE);
+ if (!mpc)
+ return 0;
+
size = mpc->length;
early_memunmap(mpc, PAGE_SIZE);
apic_printk(APIC_VERBOSE, " mpc: %lx-%lx\n", physptr, physptr + size);
@@ -437,7 +440,16 @@ static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
unsigned long size;

size = get_mpc_size(mpf->physptr);
+ if (!size) {
+ pr_err("MPTABLE: error getting MP table size\n");
+ return -1;
+ }
+
mpc = early_memremap(mpf->physptr, size);
+ if (!mpc) {
+ pr_err("MPTABLE: error mapping MP table physptr\n");
+ return -1;
+ }

/*
* Read the physical hardware table. Anything here will
@@ -552,6 +564,7 @@ void __init default_get_smp_config(unsigned int early)

static void __init smp_reserve_memory(struct mpf_intel *mpf)
{
+ /* If get_mpc_size() is 0, memblock_reserve() will just do nothing */
memblock_reserve(mpf->physptr, get_mpc_size(mpf->physptr));
}

@@ -567,6 +580,11 @@ static int __init smp_scan_config(unsigned long base, unsigned long length)

while (length > 0) {
bp = early_memremap(base, length);
+ if (!bp) {
+ pr_err("MPTABLE: error mapping SMP config\n");
+ return 0;
+ }
+
mpf = (struct mpf_intel *)bp;
if ((*bp == SMP_MAGIC_IDENT) &&
(mpf->length == 1) &&
@@ -864,6 +882,11 @@ static int __init update_mp_table(void)
goto do_unmap_mpf;

size = get_mpc_size(mpf->physptr);
+ if (!size) {
+ pr_err("MPTABLE: error getting MP table size\n");
+ goto do_unmap_mpf;
+ }
+
mpc = early_memremap(mpf->physptr, size);
if (!mpc) {
pr_err("MPTABLE: mpc early_memremap() failed\n");
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index c95b9ac..824e901 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -345,6 +345,11 @@ static void __init parse_setup_data(void)
u32 data_len, data_type;

data = early_memremap(pa_data, sizeof(*data));
+ if (!data) {
+ pr_warn("setup: failed to memremap in parse_setup_data\n");
+ return;
+ }
+
data_len = data->len + sizeof(struct setup_data);
data_type = data->type;
pa_next = data->next;
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 517a9d8..6182c5b 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -64,6 +64,8 @@ static void __init reserve_shared_info(void)

memblock_reserve(pa, PAGE_SIZE);
HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
+ if (!HYPERVISOR_shared_info)
+ panic("xen: failed to memmap hypervisor shared page: 0x%llx\n", pa);
}

static void __init xen_hvm_init_mem_mapping(void)
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 0035486..2aff5c6 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -1823,6 +1823,8 @@ static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
unsigned long val;

vaddr = early_memremap_ro(addr, sizeof(val));
+ if (!vaddr)
+ panic("xen: failed to memmap physical address: 0x%llx\n", addr);
val = *vaddr;
early_memunmap(vaddr, sizeof(val));
return val;
@@ -1918,14 +1920,20 @@ void __init xen_relocate_p2m(void)
new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
pud = early_memremap(pud_phys, PAGE_SIZE);
+ if (!pud)
+ panic("xen: failed to memmap PUD physical address: 0x%llx\n", pud_phys);
clear_page(pud);
for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
idx_pmd++) {
pmd = early_memremap(pmd_phys, PAGE_SIZE);
+ if (!pmd)
+ panic("xen: failed to memmap PMD physical address: 0x%llx\n", pmd_phys);
clear_page(pmd);
for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
idx_pt++) {
pt = early_memremap(pt_phys, PAGE_SIZE);
+ if (!pt)
+ panic("xen: failed to memmap PT physical address: 0x%llx\n", pt_phys);
clear_page(pt);
for (idx_pte = 0;
idx_pte < min(n_pte, PTRS_PER_PTE);
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 81aa46f..5e74496 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -685,6 +685,8 @@ static void __init xen_phys_memcpy(phys_addr_t dest, phys_addr_t src,
len = min(dest_len, src_len);
to = early_memremap(dest - dest_off, dest_len + dest_off);
from = early_memremap(src - src_off, src_len + src_off);
+ if (!to || !from)
+ panic("xen: failed to memmap for physical address memcpy\n");
memcpy(to, from, len);
early_memunmap(to, dest_len + dest_off);
early_memunmap(from, src_len + src_off);
--
1.8.3.1
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