Re: [PATCH V2] Add guards around [nfsidmap] usages of [sysconf].

[Steve Dickson <steved@xxxxxxxxxx>]

On 12/1/24 10:36 AM, Bogdan-Cristian Ttroiu wrote:
> From: Bogdan-Cristian Tătăroiu <b.tataroiu@xxxxxxxxx>
>
> sysconf(_SC_GETPW_R_SIZE_MAX) and sysconf(_SC_GETGR_R_SIZE_MAX)
> return -1 on musl, which causes either segmentation faults or ENOMEM
> errors.
>
> Replace all usages of sysconf with dedicated methods that guard against
> a result of -1.
Committed... (tag: nfs-utils-2-8-2-rc4)

steved.

> ---
>   support/nfsidmap/gums.c             |  4 ++--
>   support/nfsidmap/libnfsidmap.c      |  4 ++--
>   support/nfsidmap/nfsidmap_common.c  | 16 ++++++++++++++++
>   support/nfsidmap/nfsidmap_private.h |  2 ++
>   support/nfsidmap/nss.c              |  8 ++++----
>   support/nfsidmap/regex.c            |  9 +++++----
>   support/nfsidmap/static.c           |  5 +++--
>   7 files changed, 34 insertions(+), 14 deletions(-)
>
> diff --git a/support/nfsidmap/gums.c b/support/nfsidmap/gums.c
> index 1d6eb318..e94a4c50 100644
> --- a/support/nfsidmap/gums.c
> +++ b/support/nfsidmap/gums.c
> @@ -475,7 +475,7 @@ static int translate_to_uid(char *local_uid, uid_t *uid, uid_t *gid)
>   	int ret = -1;
>   	struct passwd *pw = NULL;
>   	struct pwbuf *buf = NULL;
> -	size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
> +	size_t buflen = get_pwnam_buflen();
>   
>   	buf = malloc(sizeof(*buf) + buflen);
>   	if (buf == NULL)
> @@ -501,7 +501,7 @@ static int translate_to_gid(char *local_gid, uid_t *gid)
>   	struct group *gr = NULL;
>   	struct group grbuf;
>   	char *buf = NULL;
> -	size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
> +	size_t buflen = get_grnam_buflen();
>   	int ret = -1;
>   
>   	do {
> diff --git a/support/nfsidmap/libnfsidmap.c b/support/nfsidmap/libnfsidmap.c
> index f8c36480..e1475879 100644
> --- a/support/nfsidmap/libnfsidmap.c
> +++ b/support/nfsidmap/libnfsidmap.c
> @@ -457,7 +457,7 @@ int nfs4_init_name_mapping(char *conffile)
>   
>   	nobody_user = conf_get_str("Mapping", "Nobody-User");
>   	if (nobody_user) {
> -		size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
> +		size_t buflen = get_pwnam_buflen();
>   		struct passwd *buf;
>   		struct passwd *pw = NULL;
>   		int err;
> @@ -478,7 +478,7 @@ int nfs4_init_name_mapping(char *conffile)
>   
>   	nobody_group = conf_get_str("Mapping", "Nobody-Group");
>   	if (nobody_group) {
> -		size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
> +		size_t buflen = get_grnam_buflen();
>   		struct group *buf;
>   		struct group *gr = NULL;
>   		int err;
> diff --git a/support/nfsidmap/nfsidmap_common.c b/support/nfsidmap/nfsidmap_common.c
> index 4d2cb14f..1d5b542b 100644
> --- a/support/nfsidmap/nfsidmap_common.c
> +++ b/support/nfsidmap/nfsidmap_common.c
> @@ -116,3 +116,19 @@ int get_reformat_group(void)
>   
>   	return reformat_group;
>   }
> +
> +size_t get_pwnam_buflen(void)
> +{
> +	long buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
> +	if (buflen == -1)
> +		buflen = 16384;
> +	return (size_t)buflen;
> +}
> +
> +size_t get_grnam_buflen(void)
> +{
> +	long buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
> +	if (buflen == -1)
> +		buflen = 16384;
> +	return (size_t)buflen;
> +}
> diff --git a/support/nfsidmap/nfsidmap_private.h b/support/nfsidmap/nfsidmap_private.h
> index a5cb6dda..234ca9d4 100644
> --- a/support/nfsidmap/nfsidmap_private.h
> +++ b/support/nfsidmap/nfsidmap_private.h
> @@ -40,6 +40,8 @@ struct conf_list *get_local_realms(void);
>   void free_local_realms(void);
>   int get_nostrip(void);
>   int get_reformat_group(void);
> +size_t get_pwnam_buflen(void);
> +size_t get_grnam_buflen(void);
>   
>   typedef enum {
>   	IDTYPE_USER = 1,
> diff --git a/support/nfsidmap/nss.c b/support/nfsidmap/nss.c
> index 0f43076e..3fc045dc 100644
> --- a/support/nfsidmap/nss.c
> +++ b/support/nfsidmap/nss.c
> @@ -91,7 +91,7 @@ static int nss_uid_to_name(uid_t uid, char *domain, char *name, size_t len)
>   	struct passwd *pw = NULL;
>   	struct passwd pwbuf;
>   	char *buf;
> -	size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
> +	size_t buflen = get_pwnam_buflen();
>   	int err = -ENOMEM;
>   
>   	buf = malloc(buflen);
> @@ -119,7 +119,7 @@ static int nss_gid_to_name(gid_t gid, char *domain, char *name, size_t len)
>   	struct group *gr = NULL;
>   	struct group grbuf;
>   	char *buf;
> -	size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
> +	size_t buflen = get_grnam_buflen();
>   	int err;
>   
>   	if (domain == NULL)
> @@ -192,7 +192,7 @@ static struct passwd *nss_getpwnam(const char *name, const char *domain,
>   {
>   	struct passwd *pw;
>   	struct pwbuf *buf;
> -	size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
> +	size_t buflen = get_pwnam_buflen();
>   	char *localname;
>   	int err = ENOMEM;
>   
> @@ -301,7 +301,7 @@ static int _nss_name_to_gid(char *name, gid_t *gid, int dostrip)
>   	struct group *gr = NULL;
>   	struct group grbuf;
>   	char *buf, *domain;
> -	size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
> +	size_t buflen = get_grnam_buflen();
>   	int err = -EINVAL;
>   	char *localname = NULL;
>   	char *ref_name = NULL;
> diff --git a/support/nfsidmap/regex.c b/support/nfsidmap/regex.c
> index 8424179f..ea094b95 100644
> --- a/support/nfsidmap/regex.c
> +++ b/support/nfsidmap/regex.c
> @@ -46,6 +46,7 @@
>   
>   #include "nfsidmap.h"
>   #include "nfsidmap_plugin.h"
> +#include "nfsidmap_private.h"
>   
>   #define CONFIG_GET_STRING nfsidmap_config_get
>   extern const char *nfsidmap_config_get(const char *, const char *);
> @@ -95,7 +96,7 @@ static struct passwd *regex_getpwnam(const char *name, const char *UNUSED(domain
>   {
>   	struct passwd *pw;
>   	struct pwbuf *buf;
> -	size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
> +	size_t buflen = get_pwnam_buflen();
>   	char *localname;
>   	size_t namelen;
>   	int err;
> @@ -175,7 +176,7 @@ static struct group *regex_getgrnam(const char *name, const char *UNUSED(domain)
>   {
>   	struct group *gr;
>   	struct grbuf *buf;
> -	size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
> +	size_t buflen = get_grnam_buflen();
>   	char *localgroup;
>   	char *groupname;
>   	size_t namelen;
> @@ -366,7 +367,7 @@ static int regex_uid_to_name(uid_t uid, char *domain, char *name, size_t len)
>   	struct passwd *pw = NULL;
>   	struct passwd pwbuf;
>   	char *buf;
> -	size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
> +	size_t buflen = get_pwnam_buflen();
>   	int err = -ENOMEM;
>   
>   	buf = malloc(buflen);
> @@ -392,7 +393,7 @@ static int regex_gid_to_name(gid_t gid, char *UNUSED(domain), char *name, size_t
>   	struct group grbuf;
>   	char *buf;
>       const char *name_prefix;
> -	size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
> +	size_t buflen = get_grnam_buflen();
>   	int err;
>       char * groupname = NULL;
>   
> diff --git a/support/nfsidmap/static.c b/support/nfsidmap/static.c
> index 8ac4a398..395cac06 100644
> --- a/support/nfsidmap/static.c
> +++ b/support/nfsidmap/static.c
> @@ -44,6 +44,7 @@
>   #include "conffile.h"
>   #include "nfsidmap.h"
>   #include "nfsidmap_plugin.h"
> +#include "nfsidmap_private.h"
>   
>   /*
>    * Static Translation Methods
> @@ -98,7 +99,7 @@ static struct passwd *static_getpwnam(const char *name,
>   {
>   	struct passwd *pw;
>   	struct pwbuf *buf;
> -	size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
> +	size_t buflen = get_pwnam_buflen();
>   	char *localname;
>   	int err;
>   
> @@ -149,7 +150,7 @@ static struct group *static_getgrnam(const char *name,
>   {
>   	struct group *gr;
>   	struct grbuf *buf;
> -	size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
> +	size_t buflen = get_grnam_buflen();
>   	char *localgroup;
>   	int err;
>