Re: [PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds

2021-05-15 Thread Michael Ellerman 
On Sat, 8 May 2021 06:36:21 + (UTC), Christophe Leroy wrote:
> UBSAN complains when a pointer is calculated with invalid
> 'legacy_serial_console' index, allthough the index is verified
> before dereferencing the pointer.
> 
> Fix it by checking 'legacy_serial_console' validity before
> calculating pointers.

Applied to powerpc/fixes.

[1/1] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds
  https://git.kernel.org/powerpc/c/63970f3c37e75997ed86dbdfdc83df35f2152bb1

cheers

Re: [PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds

2021-05-10 Thread Christophe Leroy 




Le 11/05/2021 à 03:16, Michael Ellerman a écrit :

Segher Boessenkool  writes:


On Sat, May 08, 2021 at 06:36:21AM +, Christophe Leroy wrote:

UBSAN complains when a pointer is calculated with invalid
'legacy_serial_console' index, allthough the index is verified
before dereferencing the pointer.


Addressing like this is UB already.

You could just move this:


-   if (legacy_serial_console < 0)
-   return 0;


to before


-   struct legacy_serial_info *info = 
&legacy_serial_infos[legacy_serial_console];
-   struct plat_serial8250_port *port = 
&legacy_serial_ports[legacy_serial_console];


and no other change is necessary.


Yeah I sent a v2 doing that, thanks.



I wanted something looking similar to setup_legacy_serial_console(), but of 
course this also works.

Christophe

Re: [PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds

2021-05-10 Thread Michael Ellerman 
Segher Boessenkool  writes:

> On Sat, May 08, 2021 at 06:36:21AM +, Christophe Leroy wrote:
>> UBSAN complains when a pointer is calculated with invalid
>> 'legacy_serial_console' index, allthough the index is verified
>> before dereferencing the pointer.
>
> Addressing like this is UB already.
>
> You could just move this:
>
>> -if (legacy_serial_console < 0)
>> -return 0;
>
> to before
>
>> -struct legacy_serial_info *info = 
>> &legacy_serial_infos[legacy_serial_console];
>> -struct plat_serial8250_port *port = 
>> &legacy_serial_ports[legacy_serial_console];
>
> and no other change is necessary.

Yeah I sent a v2 doing that, thanks.

cheers

Re: [PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds

2021-05-10 Thread Segher Boessenkool 
On Sat, May 08, 2021 at 06:36:21AM +, Christophe Leroy wrote:
> UBSAN complains when a pointer is calculated with invalid
> 'legacy_serial_console' index, allthough the index is verified
> before dereferencing the pointer.

Addressing like this is UB already.

You could just move this:

> - if (legacy_serial_console < 0)
> - return 0;

to before

> - struct legacy_serial_info *info = 
> &legacy_serial_infos[legacy_serial_console];
> - struct plat_serial8250_port *port = 
> &legacy_serial_ports[legacy_serial_console];

and no other change is necessary.


Segher

[PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds

2021-05-07 Thread Christophe Leroy 
UBSAN complains when a pointer is calculated with invalid
'legacy_serial_console' index, allthough the index is verified
before dereferencing the pointer.

Fix it by checking 'legacy_serial_console' validity before
calculating pointers.

Fixes: 0bd3f9e953bd ("powerpc/legacy_serial: Use early_ioremap()")
Reported-by: Paul Menzel 
Signed-off-by: Christophe Leroy 
---
 arch/powerpc/kernel/legacy_serial.c | 16 ++--
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/legacy_serial.c 
b/arch/powerpc/kernel/legacy_serial.c
index 8b2c1a8553a0..1c2e09e1d59b 100644
--- a/arch/powerpc/kernel/legacy_serial.c
+++ b/arch/powerpc/kernel/legacy_serial.c
@@ -354,15 +354,12 @@ static void __init setup_legacy_serial_console(int 
console)
udbg_uart_setup(info->speed, info->clock);
 }
 
-static int __init ioremap_legacy_serial_console(void)
+static int __init do_ioremap_legacy_serial_console(int console)
 {
-   struct legacy_serial_info *info = 
&legacy_serial_infos[legacy_serial_console];
-   struct plat_serial8250_port *port = 
&legacy_serial_ports[legacy_serial_console];
+   struct legacy_serial_info *info = &legacy_serial_infos[console];
+   struct plat_serial8250_port *port = &legacy_serial_ports[console];
void __iomem *vaddr;
 
-   if (legacy_serial_console < 0)
-   return 0;
-
if (!info->early_addr)
return 0;
 
@@ -376,6 +373,13 @@ static int __init ioremap_legacy_serial_console(void)
 
return 0;
 }
+
+static int __init ioremap_legacy_serial_console(void)
+{
+   if (legacy_serial_console < 0)
+   return 0;
+   return do_ioremap_legacy_serial_console(legacy_serial_console);
+}
 early_initcall(ioremap_legacy_serial_console);
 
 /*
-- 
2.25.0