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Commit f2a681b9 authored by James Morse's avatar James Morse Committed by Rafael J. Wysocki
Browse files

ACPI / APEI: Make GHES estatus header validation more user friendly 



ghes_read_estatus() checks various lengths in the top-level header to
ensure the CPER records to be read aren't obviously corrupt.

Take the opportunity to make this more user-friendly, printing a
(ratelimited) message about the nature of the header format error.

Suggested-by: default avatarBorislav Petkov <bp@alien8.de>
Signed-off-by: default avatarJames Morse <james.morse@arm.com>
[ rjw: Add missing 'static' ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent f2a7e059

drivers/acpi/apei/ghes.c

+32 −14
Original line number Diff line number Diff line
@@ -293,6 +293,30 @@ static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len, 
	}

}



/* Check the top-level record header has an appropriate size. */

static int __ghes_check_estatus(struct ghes *ghes,

				struct acpi_hest_generic_status *estatus)

{

	u32 len = cper_estatus_len(estatus);



	if (len < sizeof(*estatus)) {

		pr_warn_ratelimited(FW_WARN GHES_PFX "Truncated error status block!\n");

		return -EIO;

	}



	if (len > ghes->generic->error_block_length) {

		pr_warn_ratelimited(FW_WARN GHES_PFX "Invalid error status block length!\n");

		return -EIO;

	}



	if (cper_estatus_check_header(estatus)) {

		pr_warn_ratelimited(FW_WARN GHES_PFX "Invalid CPER header!\n");

		return -EIO;

	}



	return 0;

}



static int ghes_read_estatus(struct ghes *ghes,

			     struct acpi_hest_generic_status *estatus,

			     u64 *buf_paddr, enum fixed_addresses fixmap_idx)
@@ -319,27 +343,21 @@ static int ghes_read_estatus(struct ghes *ghes, 
		return -ENOENT;

	}



	rc = -EIO;

	rc = __ghes_check_estatus(ghes, estatus);

	if (rc)

		return rc;



	len = cper_estatus_len(estatus);

	if (len < sizeof(*estatus))

		goto err_read_block;

	if (len > ghes->generic->error_block_length)

		goto err_read_block;

	if (cper_estatus_check_header(estatus))

		goto err_read_block;

	ghes_copy_tofrom_phys(estatus + 1,

			      *buf_paddr + sizeof(*estatus),

			      len - sizeof(*estatus), 1, fixmap_idx);

	if (cper_estatus_check(estatus))

		goto err_read_block;

	rc = 0;



err_read_block:

	if (rc)

	if (cper_estatus_check(estatus)) {

		pr_warn_ratelimited(FW_WARN GHES_PFX

				    "Failed to read error status block!\n");

		return -EIO;

	}



	return rc;

	return 0;

}



static void ghes_clear_estatus(struct ghes *ghes,