Re: [PATCH] disas: sparc: Fix integer overflow in compare_opcodes() for loop

Le 27/05/2026 à 19:57, Christian Barry a écrit :
> From: Christian Barry <[email protected]>
> 
> Replaced left-shift of a literal 1 by i inside of two for loops in compare_opcodes() with a call to BIT(i). This makes it so 1 is interpreted as an unsigned long int, preventing overflows.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/2618
> 
> Signed-off-by: Christian Barry <[email protected]>
> Co-developed-by: Eduardo Augusto Cavalcanti <[email protected]>
> Signed-off-by: Eduardo Augusto Cavalcanti <[email protected]>

Reviewed-by: Laurent Vivier <[email protected]>

> ---
>   disas/sparc.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/disas/sparc.c b/disas/sparc.c
> index 5689533ce1..6fc057e3a2 100644
> --- a/disas/sparc.c
> +++ b/disas/sparc.c
> @@ -27,6 +27,7 @@
>      see <http://www.gnu.org/licenses/>.  */
>   
>   #include "qemu/osdep.h"
> +#include "qemu/bitops.h"
>   #include "disas/dis-asm.h"
>   
>   /* The SPARC opcode table (and other related data) is defined in
> @@ -2515,7 +2516,7 @@ compare_opcodes (const void * a, const void * b)
>        another, it is important to order the opcodes in the right order.  */
>     for (i = 0; i < 32; ++i)
>       {
> -      unsigned long int x = 1 << i;
> +      unsigned long int x = BIT(i);
>         int x0 = (match0 & x) != 0;
>         int x1 = (match1 & x) != 0;
>   
> @@ -2525,7 +2526,7 @@ compare_opcodes (const void * a, const void * b)
>   
>     for (i = 0; i < 32; ++i)
>       {
> -      unsigned long int x = 1 << i;
> +      unsigned long int x = BIT(i);
>         int x0 = (lose0 & x) != 0;
>         int x1 = (lose1 & x) != 0;
>