[PATCH v1 2/2] ACPI/PRM: Handle memory allocation and memory remap failure

From: Aubrey Li
Date: Tue Oct 19 2021 - 23:23:37 EST


Handle memory allocation and memory remap failure in acpi_parse_prmt()
when system runs out of memory to avoid the potential NULL pointer
dereference errors.

Signed-off-by: Aubrey Li <aubrey.li@xxxxxxxxxxxxxxx>
---
drivers/acpi/prmt.c | 31 ++++++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
index aa02221..4d3a219 100644
--- a/drivers/acpi/prmt.c
+++ b/drivers/acpi/prmt.c
@@ -96,7 +96,7 @@ acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end)
struct acpi_prmt_handler_info *handler_info;
struct prm_handler_info *th;
struct prm_module_info *tm;
- u64 mmio_count = 0;
+ u64 *mmio_count;
u64 cur_handler = 0;
u32 module_info_size = 0;
u64 mmio_range_size = 0;
@@ -105,6 +105,8 @@ acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end)
module_info = (struct acpi_prmt_module_info *) header;
module_info_size = struct_size(tm, handlers, module_info->handler_info_count);
tm = kmalloc(module_info_size, GFP_KERNEL);
+ if (!tm)
+ goto parse_prmt_out1;

guid_copy(&tm->guid, (guid_t *) module_info->module_guid);
tm->major_rev = module_info->major_rev;
@@ -117,14 +119,24 @@ acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end)
* Each module is associated with a list of addr
* ranges that it can use during the service
*/
- mmio_count = *(u64 *) memremap(module_info->mmio_list_pointer, 8, MEMREMAP_WB);
- mmio_range_size = struct_size(tm->mmio_info, addr_ranges, mmio_count);
+ mmio_count = (u64 *) memremap(module_info->mmio_list_pointer, 8, MEMREMAP_WB);
+ if (!mmio_count)
+ goto parse_prmt_out2;
+
+ mmio_range_size = struct_size(tm->mmio_info, addr_ranges, *mmio_count);
tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL);
+ if (!tm->mmio_info)
+ goto parse_prmt_out3;
+
temp_mmio = memremap(module_info->mmio_list_pointer, mmio_range_size, MEMREMAP_WB);
+ if (!temp_mmio)
+ goto parse_prmt_out4;
memmove(tm->mmio_info, temp_mmio, mmio_range_size);
} else {
- mmio_range_size = struct_size(tm->mmio_info, addr_ranges, mmio_count);
- tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL);
+ tm->mmio_info = kmalloc(sizeof(*tm->mmio_info), GFP_KERNEL);
+ if (!tm->mmio_info)
+ goto parse_prmt_out2;
+
tm->mmio_info->mmio_count = 0;
}

@@ -142,6 +154,15 @@ acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end)
} while (++cur_handler < tm->handler_count && (handler_info = get_next_handler(handler_info)));

return 0;
+
+parse_prmt_out4:
+ kfree(tm->mmio_info);
+parse_prmt_out3:
+ memunmap(mmio_count);
+parse_prmt_out2:
+ kfree(tm);
+parse_prmt_out1:
+ return -ENOMEM;
}

#define GET_MODULE 0
--
2.7.4