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

Steve Dickson <steved@xxxxxxxxxx> · Sat, 9 Nov 2024 12:25:18 -0600

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@xxxxxxxxx>
---
  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;








