[PATCH] libmultipath: fix memory leak in _check_bindings_file

[PATCH] libmultipath: fix memory leak in _check_bindings_file

[mwilck]

From: Martin Wilck <mwilck@suse.com>

We must pass "&line" to the cleanup function, not "line".

Fixes: "libmultipath: add consistency check for alias settings"
Signed-off-by: Martin Wilck <mwilck@suse.com>
---
 libmultipath/alias.c | 2 +-
 libmultipath/util.c  | 8 ++++++++
 libmultipath/util.h  | 1 +
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/libmultipath/alias.c b/libmultipath/alias.c
index de28f25..a7ba485 100644
--- a/libmultipath/alias.c
+++ b/libmultipath/alias.c
@@ -580,7 +580,7 @@ static int _check_bindings_file(const struct config *conf, FILE *file,
 	size_t line_len = 0;
 	ssize_t n;
 
-	pthread_cleanup_push(free, line);
+	pthread_cleanup_push(cleanup_free_ptr, &line);
 	while ((n = getline(&line, &line_len, file)) >= 0) {
 		char *c, *alias, *wwid, *saveptr;
 		const char *mpe_wwid;
diff --git a/libmultipath/util.c b/libmultipath/util.c
index 8412d30..395c710 100644
--- a/libmultipath/util.c
+++ b/libmultipath/util.c
@@ -406,6 +406,14 @@ void cleanup_mutex(void *arg)
 	pthread_mutex_unlock(arg);
 }
 
+void cleanup_free_ptr(void *arg)
+{
+	void **p = arg;
+
+	if (p && *p)
+		free(*p);
+}
+
 struct bitfield *alloc_bitfield(unsigned int maxbit)
 {
 	unsigned int n;
diff --git a/libmultipath/util.h b/libmultipath/util.h
index 94ed872..21a4088 100644
--- a/libmultipath/util.h
+++ b/libmultipath/util.h
@@ -49,6 +49,7 @@ int should_exit(void);
 
 void close_fd(void *arg);
 void cleanup_mutex(void *arg);
+void cleanup_free_ptr(void *arg);
 
 struct scandir_result {
 	struct dirent **di;
-- 
2.28.0

Re: [PATCH] libmultipath: fix memory leak in _check_bindings_file

[Benjamin Marzinski]

On Wed, Sep 16, 2020 at 06:26:58PM +0200, mwilck@suse.com wrote:
> From: Martin Wilck <mwilck@suse.com>
> 
> We must pass "&line" to the cleanup function, not "line".


Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
 
> Fixes: "libmultipath: add consistency check for alias settings"
> Signed-off-by: Martin Wilck <mwilck@suse.com>
> ---
>  libmultipath/alias.c | 2 +-
>  libmultipath/util.c  | 8 ++++++++
>  libmultipath/util.h  | 1 +
>  3 files changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/libmultipath/alias.c b/libmultipath/alias.c
> index de28f25..a7ba485 100644
> --- a/libmultipath/alias.c
> +++ b/libmultipath/alias.c
> @@ -580,7 +580,7 @@ static int _check_bindings_file(const struct config *conf, FILE *file,
>  	size_t line_len = 0;
>  	ssize_t n;
>  
> -	pthread_cleanup_push(free, line);
> +	pthread_cleanup_push(cleanup_free_ptr, &line);
>  	while ((n = getline(&line, &line_len, file)) >= 0) {
>  		char *c, *alias, *wwid, *saveptr;
>  		const char *mpe_wwid;
> diff --git a/libmultipath/util.c b/libmultipath/util.c
> index 8412d30..395c710 100644
> --- a/libmultipath/util.c
> +++ b/libmultipath/util.c
> @@ -406,6 +406,14 @@ void cleanup_mutex(void *arg)
>  	pthread_mutex_unlock(arg);
>  }
>  
> +void cleanup_free_ptr(void *arg)
> +{
> +	void **p = arg;
> +
> +	if (p && *p)
> +		free(*p);
> +}
> +
>  struct bitfield *alloc_bitfield(unsigned int maxbit)
>  {
>  	unsigned int n;
> diff --git a/libmultipath/util.h b/libmultipath/util.h
> index 94ed872..21a4088 100644
> --- a/libmultipath/util.h
> +++ b/libmultipath/util.h
> @@ -49,6 +49,7 @@ int should_exit(void);
>  
>  void close_fd(void *arg);
>  void cleanup_mutex(void *arg);
> +void cleanup_free_ptr(void *arg);
>  
>  struct scandir_result {
>  	struct dirent **di;
> -- 
> 2.28.0