[PATCH] perf record: Fix failed memory allocation for get_cpuid_str

[PATCH] perf record: Fix failed memory allocation for get_cpuid_str

[Thomas Richter]

In x86 architecture dependend part function
get_cpuid_str() mallocs a 128 byte buffer, but does not
check if the memory allocation succeeded or not.
When the memory allocation fails, function __get_cpuid()
is called with first parameter being a NULL pointer.
However this function references its first parameter
and operates on a NULL pointer which might cause core
dumps.

Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
---
 tools/perf/arch/x86/util/header.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/arch/x86/util/header.c b/tools/perf/arch/x86/util/header.c
index 33027c5e6f92..c6b5204e0280 100644
--- a/tools/perf/arch/x86/util/header.c
+++ b/tools/perf/arch/x86/util/header.c
@@ -70,7 +70,7 @@ get_cpuid_str(void)
 {
 	char *buf = malloc(128);
 
-	if (__get_cpuid(buf, 128, "%s-%u-%X$") < 0) {
+	if (buf && __get_cpuid(buf, 128, "%s-%u-%X$") < 0) {
 		free(buf);
 		return NULL;
 	}
-- 
2.13.4

Re: [PATCH] perf record: Fix failed memory allocation for get_cpuid_str

[Arnaldo Carvalho de Melo]

Em Wed, Jan 17, 2018 at 02:16:11PM +0100, Thomas Richter escreveu:
> In x86 architecture dependend part function
> get_cpuid_str() mallocs a 128 byte buffer, but does not
> check if the memory allocation succeeded or not.
> When the memory allocation fails, function __get_cpuid()
> is called with first parameter being a NULL pointer.
> However this function references its first parameter
> and operates on a NULL pointer which might cause core
> dumps.

Thanks, applied.

- Arnaldo
 
> Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
> ---
>  tools/perf/arch/x86/util/header.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/perf/arch/x86/util/header.c b/tools/perf/arch/x86/util/header.c
> index 33027c5e6f92..c6b5204e0280 100644
> --- a/tools/perf/arch/x86/util/header.c
> +++ b/tools/perf/arch/x86/util/header.c
> @@ -70,7 +70,7 @@ get_cpuid_str(void)
>  {
>  	char *buf = malloc(128);
>  
> -	if (__get_cpuid(buf, 128, "%s-%u-%X$") < 0) {
> +	if (buf && __get_cpuid(buf, 128, "%s-%u-%X$") < 0) {
>  		free(buf);
>  		return NULL;
>  	}
> -- 
> 2.13.4

[tip:perf/core] perf record: Fix failed memory allocation for get_cpuid_str

[tip-bot for Thomas Richter]

Commit-ID:  81fccd6ca507d3b2012eaf1edeb9b1dbf4bd22db
Gitweb:     https://git.kernel.org/tip/81fccd6ca507d3b2012eaf1edeb9b1dbf4bd22db
Author:     Thomas Richter <tmricht@linux.vnet.ibm.com>
AuthorDate: Wed, 17 Jan 2018 14:16:11 +0100
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 17 Jan 2018 10:31:25 -0300

perf record: Fix failed memory allocation for get_cpuid_str

In x86 architecture dependend part function get_cpuid_str() mallocs a
128 byte buffer, but does not check if the memory allocation succeeded
or not.

When the memory allocation fails, function __get_cpuid() is called with
first parameter being a NULL pointer.  However this function references
its first parameter and operates on a NULL pointer which might cause
core dumps.

Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20180117131611.34319-1-tmricht@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/arch/x86/util/header.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/arch/x86/util/header.c b/tools/perf/arch/x86/util/header.c
index b626d2b..fb0d71a 100644
--- a/tools/perf/arch/x86/util/header.c
+++ b/tools/perf/arch/x86/util/header.c
@@ -70,7 +70,7 @@ get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
 {
 	char *buf = malloc(128);
 
-	if (__get_cpuid(buf, 128, "%s-%u-%X$") < 0) {
+	if (buf && __get_cpuid(buf, 128, "%s-%u-%X$") < 0) {
 		free(buf);
 		return NULL;
 	}