[PATCH v4 05/13] ACPI: extlog: Avoid populating software AER metadata from raw hardware buffer

extlog_print_pcie() casts pcie_err->aer_info straight to struct
aer_capability_regs *. That struct embeds struct pcie_tlp_log, whose
software-only header_len and flit fields sit at offset 84 - inside the
96-byte aer_info buffer - so the cast fills them with raw firmware bytes.
pcie_print_tlp_log() uses both to bound a loop over dw[], and a large
header_len walks past the end of the array.

Copy aer_info into a zeroed local struct aer_capability_regs and clear
header_len and flit before passing it on.

Reported-by: [email protected]
Closes: https://lore.kernel.org/linux-cxl/[email protected]/
Fixes: e778ffefa34d ("ACPI: extlog: Trace CPER PCI Express Error Section")
Reviewed-by: Alison Schofield <[email protected]>
Reviewed-by: Shuai Xue <[email protected]>
Assisted-by: Claude:claude-sonnet-4-6
Signed-off-by: Dave Jiang <[email protected]>
---
v4:
- Dropped the now-pointless aer pointer alias.
---
 drivers/acpi/acpi_extlog.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
index f6e3da4e13e7..6d5532ec0920 100644
--- a/drivers/acpi/acpi_extlog.c
+++ b/drivers/acpi/acpi_extlog.c
@@ -137,7 +137,7 @@ static void extlog_print_pcie(struct cper_sec_pcie *pcie_err,
 			      int severity)
 {
 #ifdef ACPI_APEI_PCIEAER
-	struct aer_capability_regs *aer;
+	struct aer_capability_regs aer_regs = {};
 	struct pci_dev *pdev;
 	unsigned int devfn;
 	unsigned int bus;
@@ -149,7 +149,11 @@ static void extlog_print_pcie(struct cper_sec_pcie *pcie_err,
 		return;
 
 	aer_severity = cper_severity_to_aer(severity);
-	aer = (struct aer_capability_regs *)pcie_err->aer_info;
+
+	memcpy(&aer_regs, pcie_err->aer_info, sizeof(pcie_err->aer_info));
+	aer_regs.header_log.header_len = 0;
+	aer_regs.header_log.flit = false;
+
 	domain = pcie_err->device_id.segment;
 	bus = pcie_err->device_id.bus;
 	devfn = PCI_DEVFN(pcie_err->device_id.device,
@@ -158,7 +162,7 @@ static void extlog_print_pcie(struct cper_sec_pcie *pcie_err,
 	if (!pdev)
 		return;
 
-	pci_print_aer(pdev, aer_severity, aer);
+	pci_print_aer(pdev, aer_severity, &aer_regs);
 	pci_dev_put(pdev);
 #endif
 }
-- 
2.54.0