[PATCH v8 18/26] ACPI / APEI: Make GHES estatus header validation more user friendly
From: James Morse <james.morse@arm.com>
Date: 2019-01-29 18:50:37
Also in:
kvmarm, linux-acpi, linux-mm
Subsystem:
acpi, acpi apei, the rest · Maintainers:
"Rafael J. Wysocki", Linus Torvalds
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: Borislav Petkov <bp@alien8.de> Signed-off-by: James Morse <james.morse@arm.com> --- drivers/acpi/apei/ghes.c | 46 ++++++++++++++++++++++++++++------------ 1 file changed, 32 insertions(+), 14 deletions(-)
diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index f95db2398dd5..9391fff71344 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c@@ -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. */ +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,
--
2.20.1
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