Commit eae21bee authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Rafael J. Wysocki
Browse files

EFI/CPER: don't go past the ARM processor CPER record buffer 



There's a logic inside GHES/CPER to detect if the section_length
is too small, but it doesn't detect if it is too big.

Currently, if the firmware receives an ARM processor CPER record
stating that a section length is big, kernel will blindly trust
section_length, producing a very long dump. For instance, a 67
bytes record with ERR_INFO_NUM set 46198 and section length
set to 854918320 would dump a lot of data going a way past the
firmware memory-mapped area.

Fix it by adding a logic to prevent it to go past the buffer
if ERR_INFO_NUM is too big, making it report instead:

	[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1
	[Hardware Error]: event severity: recoverable
	[Hardware Error]:  Error 0, type: recoverable
	[Hardware Error]:   section_type: ARM processor error
	[Hardware Error]:   MIDR: 0xff304b2f8476870a
	[Hardware Error]:   section length: 854918320, CPER size: 67
	[Hardware Error]:   section length is too big
	[Hardware Error]:   firmware-generated error record is incorrect
	[Hardware Error]:   ERR_INFO_NUM is 46198

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: default avatarJonathan Cameron <jonathan.cameron@huawei.com>
Acked-by: default avatarArd Biesheuvel <ardb@kernel.org>
Reviewed-by: default avatarHanjun Guo <guohanjun@huawei.com>
[ rjw: Subject and changelog tweaks ]
Link: https://patch.msgid.link/41cd9f6b3ace3cdff7a5e864890849e4b1c58b63.1767871950.git.mchehab+huawei@kernel.org


Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 87880af2

drivers/firmware/efi/cper-arm.c

+8 −4
Original line number Diff line number Diff line
@@ -226,7 +226,8 @@ static void cper_print_arm_err_info(const char *pfx, u32 type, 
}



void cper_print_proc_arm(const char *pfx,

			 const struct cper_sec_proc_arm *proc)

			 const struct cper_sec_proc_arm *proc,

			 u32 length)

{

	int i, len, max_ctx_type;

	struct cper_arm_err_info *err_info;
@@ -238,9 +239,12 @@ void cper_print_proc_arm(const char *pfx, 


	len = proc->section_length - (sizeof(*proc) +

		proc->err_info_num * (sizeof(*err_info)));

	if (len < 0) {

		printk("%ssection length: %d\n", pfx, proc->section_length);

		printk("%ssection length is too small\n", pfx);



	if (len < 0 || proc->section_length > length) {

		printk("%ssection length: %d, CPER size: %d\n",

		       pfx, proc->section_length, length);

		printk("%ssection length is too %s\n", pfx,

		       (len < 0) ? "small" : "big");

		printk("%sfirmware-generated error record is incorrect\n", pfx);

		printk("%sERR_INFO_NUM is %d\n", pfx, proc->err_info_num);

		return;

drivers/firmware/efi/cper.c

+2 −1
Original line number Diff line number Diff line
@@ -659,7 +659,8 @@ cper_estatus_print_section(const char *pfx, struct acpi_hest_generic_data *gdata 


		printk("%ssection_type: ARM processor error\n", newpfx);

		if (gdata->error_data_length >= sizeof(*arm_err))

			cper_print_proc_arm(newpfx, arm_err);

			cper_print_proc_arm(newpfx, arm_err,

					    gdata->error_data_length);

		else

			goto err_section_too_small;

#endif

include/linux/cper.h

+2 −1
Original line number Diff line number Diff line
@@ -595,7 +595,8 @@ void cper_mem_err_pack(const struct cper_sec_mem_err *, 
const char *cper_mem_err_unpack(struct trace_seq *,

				struct cper_mem_err_compact *);

void cper_print_proc_arm(const char *pfx,

			 const struct cper_sec_proc_arm *proc);

			 const struct cper_sec_proc_arm *proc,

			 u32 length);

void cper_print_proc_ia(const char *pfx,

			const struct cper_sec_proc_ia *proc);

int cper_mem_err_location(struct cper_mem_err_compact *mem, char *msg);