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@xxxxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
---
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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