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

[Wang Nan <wangnan0@huawei.com>]

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.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Jiri Olsa <jolsa@kernel.org>
---
 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