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serial: 8250_pci1xxxx: Annotate struct pci1xxxx_8250 with __counted_by

PATCH In review Kees Cook 2 participants 2 messages Sep 22, 2023 – Sep 23, 2023

Subsystems (2)
TTY layer and serial drivers Microchip PCIe UART driver
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Kees Cook

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PATCH 1/1 serial: 8250_pci1xxxx: Annotate struct pci1xxxx_8250 with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).

As found with Coccinelle[1], add __counted_by for struct pci1xxxx_8250.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc Kumaravel Thiagarajan <[email protected]>
Cc Tharun Kumar P <[email protected]>
Cc Greg Kroah-Hartman <[email protected]>
Cc Jiri Slaby <[email protected]>
Cc [email protected]
Signed-off-by Kees Cook <[email protected]>
---
 drivers/tty/serial/8250/8250_pci1xxxx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/tty/serial/8250/8250_pci1xxxx.c +1 -1
index a3b25779d921..0da9847f3e91 100644
@@ -107,7 +107,7 @@ static const int logical_to_physical_port_idx[][MAX_PORTS] = {
 struct pci1xxxx_8250 {
 	unsigned int nr;
 	void __iomem *membase;
-	int line[];
+	int line[] __counted_by(nr);
 };
 
 static int pci1xxxx_get_num_ports(struct pci_dev *dev)
Signature · 1 line
2.34.1
Reviewed-by on v1 1/1
#1 lore raw
Quoted 8 lines · Kees Cook

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).

As found with Coccinelle[1], add __counted_by for struct pci1xxxx_8250.

Quoted 8 lines

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc Kumaravel Thiagarajan <[email protected]>
Cc Tharun Kumar P <[email protected]>
Cc Greg Kroah-Hartman <[email protected]>
Cc Jiri Slaby <[email protected]>
Cc [email protected]
Signed-off-by Kees Cook <[email protected]>
Reviewed-by Gustavo A. R. Silva <[email protected]>

Thanks

Signature · 1 line
Gustavo
Quoted 17 lines
---
  drivers/tty/serial/8250/8250_pci1xxxx.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
drivers/tty/serial/8250/8250_pci1xxxx.c +1 -1
index a3b25779d921..0da9847f3e91 100644
@@ -107,7 +107,7 @@ static const int logical_to_physical_port_idx[][MAX_PORTS] = {
  struct pci1xxxx_8250 {
  	unsigned int nr;
  	void __iomem *membase;
-	int line[];
+	int line[] __counted_by(nr);
  };
 
  static int pci1xxxx_get_num_ports(struct pci_dev *dev)