[PATCH AUTOSEL 4.19 46/59] arm64: hibernate: check pgd table allocation

Sasha Levin
2019-10-26T13:28:40Z

From: Pavel Tatashin <pasha.tatashin@soleen.com>

[ Upstream commit 8c551f919a73c1dfa690a70a691be1da394145e8 ]

There is a bug in create_safe_exec_page(), when page table is allocated
it is not checked that table is allocated successfully:

But it is dereferenced in: pgd_none(READ_ONCE(*pgdp)). Check that
allocation was successful.

Fixes: 82869ac57b5d ("arm64: kernel: Add support for hibernate/suspend-to-disk")
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/kernel/hibernate.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index 9859e1178e6be..dbeeeffdb9c9e 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -202,6 +202,7 @@ static int create_safe_exec_page(void *src_start, size_t length,
gfp_t mask)
{
int rc = 0;
+ pgd_t *trans_pgd;
pgd_t *pgdp;
pud_t *pudp;
pmd_t *pmdp;
@@ -216,7 +217,13 @@ static int create_safe_exec_page(void *src_start, size_t length,
memcpy((void *)dst, src_start, length);
__flush_icache_range(dst, dst + length);

- pgdp = pgd_offset_raw(allocator(mask), dst_addr);
+ trans_pgd = allocator(mask);
+ if (!trans_pgd) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ pgdp = pgd_offset_raw(trans_pgd, dst_addr);
if (pgd_none(READ_ONCE(*pgdp))) {
pudp = allocator(mask);
if (!pudp) {
--
2.20.1