RE: [PATCH] perf tools: Fix potential array out of bounce accessing

[åæéå / HIRAMATUïMASAMI]

> From: Wang Nan [mailto:wangnan0@xxxxxxxxxx]
> 
> There is a problem in dwarf-regs.c of sh, sparc and x86 that it is
> possible to make an out-of-bound array accessing when searching
> register names. This patch fixes it by replacing '<=' to '<', so when
> register (number == XXX_MAX_REGS), get_arch_regstr() returns NULL.

Oops, right!

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>

Thank you!

> 
> Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
> Cc: David S. Miller <davem@xxxxxxxxxxxxx>
> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
>  tools/perf/arch/sh/util/dwarf-regs.c    | 2 +-
>  tools/perf/arch/sparc/util/dwarf-regs.c | 2 +-
>  tools/perf/arch/x86/util/dwarf-regs.c   | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/arch/sh/util/dwarf-regs.c b/tools/perf/arch/sh/util/dwarf-regs.c
> index 0d0897f..f8dfa89 100644
> --- a/tools/perf/arch/sh/util/dwarf-regs.c
> +++ b/tools/perf/arch/sh/util/dwarf-regs.c
> @@ -51,5 +51,5 @@ const char *sh_regs_table[SH_MAX_REGS] = {
>  /* Return architecture dependent register string (for kprobe-tracer) */
>  const char *get_arch_regstr(unsigned int n)
>  {
> -	return (n <= SH_MAX_REGS) ? sh_regs_table[n] : NULL;
> +	return (n < SH_MAX_REGS) ? sh_regs_table[n] : NULL;
>  }
> diff --git a/tools/perf/arch/sparc/util/dwarf-regs.c b/tools/perf/arch/sparc/util/dwarf-regs.c
> index 92eda41..b704fdb 100644
> --- a/tools/perf/arch/sparc/util/dwarf-regs.c
> +++ b/tools/perf/arch/sparc/util/dwarf-regs.c
> @@ -39,5 +39,5 @@ const char *sparc_regs_table[SPARC_MAX_REGS] = {
>   */
>  const char *get_arch_regstr(unsigned int n)
>  {
> -	return (n <= SPARC_MAX_REGS) ? sparc_regs_table[n] : NULL;
> +	return (n < SPARC_MAX_REGS) ? sparc_regs_table[n] : NULL;
>  }
> diff --git a/tools/perf/arch/x86/util/dwarf-regs.c b/tools/perf/arch/x86/util/dwarf-regs.c
> index be22dd4..a08de0a 100644
> --- a/tools/perf/arch/x86/util/dwarf-regs.c
> +++ b/tools/perf/arch/x86/util/dwarf-regs.c
> @@ -71,5 +71,5 @@ const char *x86_64_regs_table[X86_64_MAX_REGS] = {
>  /* Return architecture dependent register string (for kprobe-tracer) */
>  const char *get_arch_regstr(unsigned int n)
>  {
> -	return (n <= ARCH_MAX_REGS) ? arch_regs_table[n] : NULL;
> +	return (n < ARCH_MAX_REGS) ? arch_regs_table[n] : NULL;
>  }
> --
> 1.8.3.4