PCI/AER: Avoid info leak in __print_tlp_header()

commit a1b7f2f upstream.

Commit fab4c25 ("PCI/AER: Add a TLP header print helper") introduced
the helper function __print_tlp_header(), but contrary to the intention,
the behaviour did change: Since we're taking the address of the parameter
t, the first 4 or 8 bytes printed will be the value of the pointer t
itself, and the remaining 12 or 8 bytes will be who-knows-what (something
from the stack).

We want to show the values of the four members of the struct
aer_header_log_regs; that can be done without ugly and error-prone casts.
On little-endian this should produce the same output as originally
intended, and since no-one has complained about getting garbage output so
far, I think big-endian should be ok too.

Fixes: fab4c25 ("PCI/AER: Add a TLP header print helper")
Signed-off-by: Rasmus Villemoes <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Villemoes

drivers/pci/pcie/aer/aerdrv_errprint.c

@@ -127,16 +127,8 @@ static const char *aer_agent_string[] = {
 static void __print_tlp_header(struct pci_dev *dev,
 			       struct aer_header_log_regs *t)
 {
-	unsigned char *tlp = (unsigned char *)&t;
-
-	dev_err(&dev->dev, "  TLP Header:"
-		" %02x%02x%02x%02x %02x%02x%02x%02x"
-		" %02x%02x%02x%02x %02x%02x%02x%02x\n",
-		*(tlp + 3), *(tlp + 2), *(tlp + 1), *tlp,
-		*(tlp + 7), *(tlp + 6), *(tlp + 5), *(tlp + 4),
-		*(tlp + 11), *(tlp + 10), *(tlp + 9),
-		*(tlp + 8), *(tlp + 15), *(tlp + 14),
-		*(tlp + 13), *(tlp + 12));
+	dev_err(&dev->dev, "  TLP Header: %08x %08x %08x %08x\n",
+		t->dw0, t->dw1, t->dw2, t->dw3);
 }
 
 static void __aer_print_error(struct pci_dev *dev,