diff mbox series

[v4,1/5] x86/PCI: Add PIRQ routing table range checks

Message ID alpine.DEB.2.21.2203301735510.22465@angie.orcam.me.uk
State New
Headers show
Series x86/PCI: Improve $PIR and add $IRT PIRQ routing support | expand

Commit Message

Maciej W. Rozycki March 31, 2022, 7:10 a.m. UTC 
Verify that the PCI IRQ Routing Table header as well as individual slot 
entries are all wholly contained within the BIOS memory area.  Do not 
even call the checksum calculator if the header would overrun the area 
and then bail out early if any slot would.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
---
New change in v4.
---
 arch/x86/pci/irq.c |   17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

linux-x86-pirq-range-check.diff
diff mbox series

Patch

Index: linux-macro/arch/x86/pci/irq.c
===================================================================
--- linux-macro.orig/arch/x86/pci/irq.c
+++ linux-macro/arch/x86/pci/irq.c
@@ -68,7 +68,8 @@  void (*pcibios_disable_irq)(struct pci_d
  *  and perform checksum verification.
  */
 
-static inline struct irq_routing_table *pirq_check_routing_table(u8 *addr)
+static inline struct irq_routing_table *pirq_check_routing_table(u8 *addr,
+								 u8 *limit)
 {
 	struct irq_routing_table *rt;
 	int i;
@@ -78,7 +79,8 @@  static inline struct irq_routing_table *
 	if (rt->signature != PIRQ_SIGNATURE ||
 	    rt->version != PIRQ_VERSION ||
 	    rt->size % 16 ||
-	    rt->size < sizeof(struct irq_routing_table))
+	    rt->size < sizeof(struct irq_routing_table) ||
+	    (limit && rt->size > limit - addr))
 		return NULL;
 	sum = 0;
 	for (i = 0; i < rt->size; i++)
@@ -99,17 +101,22 @@  static inline struct irq_routing_table *
 
 static struct irq_routing_table * __init pirq_find_routing_table(void)
 {
+	u8 * const bios_start = (u8 *)__va(0xf0000);
+	u8 * const bios_end = (u8 *)__va(0x100000);
 	u8 *addr;
 	struct irq_routing_table *rt;
 
 	if (pirq_table_addr) {
-		rt = pirq_check_routing_table((u8 *) __va(pirq_table_addr));
+		rt = pirq_check_routing_table((u8 *)__va(pirq_table_addr),
+					      NULL);
 		if (rt)
 			return rt;
 		printk(KERN_WARNING "PCI: PIRQ table NOT found at pirqaddr\n");
 	}
-	for (addr = (u8 *) __va(0xf0000); addr < (u8 *) __va(0x100000); addr += 16) {
-		rt = pirq_check_routing_table(addr);
+	for (addr = bios_start;
+	     addr < bios_end - sizeof(struct irq_routing_table);
+	     addr += 16) {
+		rt = pirq_check_routing_table(addr, bios_end);
 		if (rt)
 			return rt;
 	}