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

[Steve Dickson <steved@redhat.com>]

On 6/17/24 2:51 PM, Steve Dickson wrote:
> 
> 
> On 5/30/24 2:17 AM, Bogdan-Cristian Tătăroiu wrote:
>> 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.
> Actually sysconf() returns EINVAL not -1 since the return
> value is a size_t (unsigned long). So I needed to change
> 
>      size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
>      if (buflen == EINVAL) <<< this from -1 to EINVAL
>          buflen = 16384;
>      return buflen;
> 
> Good with that? Will this work with musl?
Just found this on my todo list... Still
interest in  have these patch committed?

steved.

> 
> steved.
> 
>>
>> Replace all usages of sysconf with dedicated methods that guard against
>> a result of -1.
>>
>> Signed-off-by: Bogdan-Cristian Tătăroiu <b.tataroiu@gmail.com>
>> ---
>>   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..310c68f0 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)
>> +{
>> +    size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
>> +    if (buflen == -1)
>> +        buflen = 16384;
>> +    return buflen;
>> +}
>> +
>> +size_t get_grnam_buflen(void)
>> +{
>> +    size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
>> +    if (buflen == -1)
>> +        buflen = 16384;
>> +    return 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;