commit ced8f8933673f4efda1d666d26a1a949602035ed

Author: Stephen Gallagher <sgallagh@redhat.com>

Date:   Fri Apr 29 22:11:09 2016 -0400

    NSS: Implement group merging support.

commit 2413e73c32fc36470885ae548631e081d66f4201

Author: Zack Weinberg <zackw@panix.com>

Date:   Mon Jul 18 09:33:21 2016 -0300

    Don't install the internal header grp-merge.h

--- glibc-2.17-c758a686/grp/Makefile

+++ glibc-2.17-c758a686/grp/Makefile

@@ -23,7 +23,8 @@

 routines := fgetgrent initgroups setgroups \

 	    getgrent getgrgid getgrnam putgrent \

-	    getgrent_r getgrgid_r getgrnam_r fgetgrent_r

+	    getgrent_r getgrgid_r getgrnam_r fgetgrent_r \

+	    grp-merge

 include ../Makeconfig

--- glibc-2.17-c758a686/grp/Versions

+++ glibc-2.17-c758a686/grp/Versions

@@ -28,4 +28,7 @@

     # g*

     getgrouplist;

   }

+  GLIBC_PRIVATE {

+    __merge_grp; __copy_grp;

+  }

 }

--- glibc-2.17-c758a686/grp/getgrgid_r.c

+++ glibc-2.17-c758a686/grp/getgrgid_r.c

@@ -18,6 +18,7 @@

 #include <grp.h>

+#include <grp-merge.h>

 #define LOOKUP_TYPE	struct group

 #define FUNCTION_NAME	getgrgid

@@ -25,5 +26,7 @@

 #define ADD_PARAMS	gid_t gid

 #define ADD_VARIABLES	gid

 #define BUFLEN		NSS_BUFLEN_GROUP

+#define DEEPCOPY_FN	__copy_grp

+#define MERGE_FN	__merge_grp

 #include <nss/getXXbyYY_r.c>

--- glibc-2.17-c758a686/grp/getgrnam_r.c

+++ glibc-2.17-c758a686/grp/getgrnam_r.c

@@ -18,6 +18,7 @@

 #include <grp.h>

+#include <grp-merge.h>

 #define LOOKUP_TYPE	struct group

 #define FUNCTION_NAME	getgrnam

@@ -25,4 +26,7 @@

 #define ADD_PARAMS	const char *name

 #define ADD_VARIABLES	name

+#define DEEPCOPY_FN	__copy_grp

+#define MERGE_FN	__merge_grp

+

 #include <nss/getXXbyYY_r.c>

--- glibc-2.17-c758a686/grp/grp-merge.c

+++ glibc-2.17-c758a686/grp/grp-merge.c

@@ -0,0 +1,186 @@

+/* Group merging implementation.

+   Copyright (C) 2016 Free Software Foundation, Inc.

+   This file is part of the GNU C Library.

+

+   The GNU C Library is free software; you can redistribute it and/or

+   modify it under the terms of the GNU Lesser General Public

+   License as published by the Free Software Foundation; either

+   version 2.1 of the License, or (at your option) any later version.

+

+   The GNU C Library is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+   Lesser General Public License for more details.

+

+   You should have received a copy of the GNU Lesser General Public

+   License along with the GNU C Library; if not, see

+   <http://www.gnu.org/licenses/>.  */

+

+#include <errno.h>

+#include <stdlib.h>

+#include <string.h>

+#include <grp.h>

+#include <grp-merge.h>

+

+#define BUFCHECK(size)			\

+  ({					\

+    do					\

+      {					\

+	if (c + (size) > buflen)	\

+          {				\

+	    free (members);		\

+	    return ERANGE;		\

+	  }				\

+      }					\

+    while (0);				\

+  })

+

+int

+internal_function

+__copy_grp (const struct group srcgrp, const size_t buflen,

+	    struct group *destgrp, char *destbuf, char **endptr)

+{

+  size_t i;

+  size_t c = 0;

+  size_t len;

+  size_t memcount;

+  char **members = NULL;

+

+  /* Copy the GID.  */

+  destgrp->gr_gid = srcgrp.gr_gid;

+

+  /* Copy the name.  */

+  len = strlen (srcgrp.gr_name) + 1;

+  BUFCHECK (len);

+  memcpy (&destbuf[c], srcgrp.gr_name, len);

+  destgrp->gr_name = &destbuf[c];

+  c += len;

+

+  /* Copy the password.  */

+  len = strlen (srcgrp.gr_passwd) + 1;

+  BUFCHECK (len);

+  memcpy (&destbuf[c], srcgrp.gr_passwd, len);

+  destgrp->gr_passwd = &destbuf[c];

+  c += len;

+

+  /* Count all of the members.  */

+  for (memcount = 0; srcgrp.gr_mem[memcount]; memcount++)

+    ;

+

+  /* Allocate a temporary holding area for the pointers to the member

+     contents, including space for a NULL-terminator.  */

+  members = malloc (sizeof (char *) * (memcount + 1));

+  if (members == NULL)

+    return ENOMEM;

+

+  /* Copy all of the group members to destbuf and add a pointer to each of

+     them into the 'members' array.  */

+  for (i = 0; srcgrp.gr_mem[i]; i++)

+    {

+      len = strlen (srcgrp.gr_mem[i]) + 1;

+      BUFCHECK (len);

+      memcpy (&destbuf[c], srcgrp.gr_mem[i], len);

+      members[i] = &destbuf[c];

+      c += len;

+    }

+  members[i] = NULL;

+

+  /* Copy the pointers from the members array into the buffer and assign them

+     to the gr_mem member of destgrp.  */

+  destgrp->gr_mem = (char **) &destbuf[c];

+  len = sizeof (char *) * (memcount + 1);

+  BUFCHECK (len);

+  memcpy (&destbuf[c], members, len);

+  c += len;

+  free (members);

+  members = NULL;

+

+  /* Save the count of members at the end.  */

+  BUFCHECK (sizeof (size_t));

+  memcpy (&destbuf[c], &memcount, sizeof (size_t));

+  c += sizeof (size_t);

+

+  if (endptr)

+    *endptr = destbuf + c;

+  return 0;

+}

+libc_hidden_def (__copy_grp)

+

+/* Check that the name, GID and passwd fields match, then

+   copy in the gr_mem array.  */

+int

+internal_function

+__merge_grp (struct group *savedgrp, char *savedbuf, char *savedend,

+	     size_t buflen, struct group *mergegrp, char *mergebuf)

+{

+  size_t c, i, len;

+  size_t savedmemcount;

+  size_t memcount;

+  size_t membersize;

+  char **members = NULL;

+

+  /* We only support merging members of groups with identical names and

+     GID values. If we hit this case, we need to overwrite the current

+     buffer with the saved one (which is functionally equivalent to

+     treating the new lookup as NSS_STATUS_NOTFOUND).  */

+  if (mergegrp->gr_gid != savedgrp->gr_gid

+      || strcmp (mergegrp->gr_name, savedgrp->gr_name))

+    return __copy_grp (*savedgrp, buflen, mergegrp, mergebuf, NULL);

+

+  /* Get the count of group members from the last sizeof (size_t) bytes in the

+     mergegrp buffer.  */

+  savedmemcount = (size_t) *(savedend - sizeof (size_t));

+

+  /* Get the count of new members to add.  */

+  for (memcount = 0; mergegrp->gr_mem[memcount]; memcount++)

+    ;

+

+  /* Create a temporary array to hold the pointers to the member values from

+     both the saved and merge groups.  */

+  membersize = savedmemcount + memcount + 1;

+  members = malloc (sizeof (char *) * membersize);

+  if (members == NULL)

+    return ENOMEM;

+

+  /* Copy in the existing member pointers from the saved group

+     Note: this is not NULL-terminated yet.  */

+  memcpy (members, savedgrp->gr_mem, sizeof (char *) * savedmemcount);

+

+  /* Back up into the savedbuf until we get back to the NULL-terminator of the

+     group member list. (This means walking back savedmemcount + 1 (char *) pointers

+     and the member count value.

+     The value of c is going to be the used length of the buffer backed up by

+     the member count and further backed up by the size of the pointers.  */

+  c = savedend - savedbuf

+      - sizeof (size_t)

+      - sizeof (char *) * (savedmemcount + 1);

+

+  /* Add all the new group members, overwriting the old NULL-terminator while

+     adding the new pointers to the temporary array.  */

+  for (i = 0; mergegrp->gr_mem[i]; i++)

+    {

+      len = strlen (mergegrp->gr_mem[i]) + 1;

+      BUFCHECK (len);

+      memcpy (&savedbuf[c], mergegrp->gr_mem[i], len);

+      members[savedmemcount + i] = &savedbuf[c];

+      c += len;

+    }

+  /* Add the NULL-terminator.  */

+  members[savedmemcount + memcount] = NULL;

+

+  /* Copy the member array back into the buffer after the member list and free

+     the member array.  */

+  savedgrp->gr_mem = (char **) &savedbuf[c];

+  len = sizeof (char *) * membersize;

+  BUFCHECK (len);

+  memcpy (&savedbuf[c], members, len);

+  c += len;

+

+  free (members);

+  members = NULL;

+

+  /* Finally, copy the results back into mergebuf, since that's the buffer

+     that we were provided by the caller.  */

+  return __copy_grp (*savedgrp, buflen, mergegrp, mergebuf, NULL);

+}

+libc_hidden_def (__merge_grp)

--- glibc-2.17-c758a686/grp/grp-merge.h

+++ glibc-2.17-c758a686/grp/grp-merge.h

@@ -0,0 +1,37 @@

+/* Group merging implementation.

+   Copyright (C) 2016 Free Software Foundation, Inc.

+   This file is part of the GNU C Library.

+

+   The GNU C Library is free software; you can redistribute it and/or

+   modify it under the terms of the GNU Lesser General Public

+   License as published by the Free Software Foundation; either

+   version 2.1 of the License, or (at your option) any later version.

+

+   The GNU C Library is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+   Lesser General Public License for more details.

+

+   You should have received a copy of the GNU Lesser General Public

+   License along with the GNU C Library; if not, see

+   <http://www.gnu.org/licenses/>.  */

+

+#ifndef _GRP_MERGE_H

+#define _GRP_MERGE_H 1

+

+#include <grp.h>

+

+/* Duplicate a grp struct (and its members). When no longer needed, the

+   calling function must free(newbuf).  */

+int

+__copy_grp (const struct group srcgrp, const size_t buflen,

+	    struct group *destgrp, char *destbuf, char **endptr)

+	    internal_function;

+

+/* Merge the member lists of two grp structs together.  */

+int

+__merge_grp (struct group *savedgrp, char *savedbuf, char *savedend,

+	     size_t buflen, struct group *mergegrp, char *mergebuf)

+	     internal_function;

+

+#endif /* _GRP_MERGE_H */

--- glibc-2.17-c758a686/include/grp-merge.h

+++ glibc-2.17-c758a686/include/grp-merge.h

@@ -0,0 +1,7 @@

+#ifndef _GRP_MERGE_H

+#include <grp/grp-merge.h>

+

+libc_hidden_proto (__copy_grp)

+libc_hidden_proto (__merge_grp)

+

+#endif /* _GRP_MERGE_H */

--- glibc-2.17-c758a686/manual/nss.texi

+++ glibc-2.17-c758a686/manual/nss.texi

@@ -180,7 +180,7 @@

 The case of the keywords is insignificant.  The @var{status}

 values are the results of a call to a lookup function of a specific

-service.  They mean

+service.  They mean:

 @ftable @samp

 @item success

@@ -204,6 +204,50 @@

 @end ftable

 @noindent

+The @var{action} values mean:

+

+@ftable @samp

+@item return

+

+If the status matches, stop the lookup process at this service

+specification.  If an entry is available, provide it to the application.

+If an error occurred, report it to the application.  In case of a prior

+@samp{merge} action, the data is combined with previous lookup results,

+as explained below.

+

+@item continue

+

+If the status matches, proceed with the lookup process at the next

+entry, discarding the result of the current lookup (and any merged

+data).  An exception is the @samp{initgroups} database and the

+@samp{success} status, where @samp{continue} acts like @code{merge}

+below.

+

+@item merge

+

+Proceed with the lookup process, retaining the current lookup result.

+This action is useful only with the @samp{success} status.  If a

+subsequent service lookup succeeds and has a matching @samp{return}

+specification, the results are merged, the lookup process ends, and the

+merged results are returned to the application.  If the following service

+has a matching @samp{merge} action, the lookup process continues,

+retaining the combined data from this and any previous lookups.

+

+After a @code{merge} action, errors from subsequent lookups are ignored,

+and the data gathered so far will be returned.

+

+The @samp{merge} only applies to the @samp{success} status.  It is

+currently implemented for the @samp{group} database and its group

+members field, @samp{gr_mem}.  If specified for other databases, it

+causes the lookup to fail (if the @var{status} matches).

+

+When processing @samp{merge} for @samp{group} membership, the group GID

+and name must be identical for both entries.  If only one or the other is

+a match, the behavior is undefined.

+

+@end ftable

+

+@noindent

 If we have a line like

 @smallexample

--- glibc-2.17-c758a686/nscd/getgrgid_r.c

+++ glibc-2.17-c758a686/nscd/getgrgid_r.c

@@ -17,6 +17,7 @@

 #include <grp.h>

+#include <grp-merge.h>

 #define LOOKUP_TYPE	struct group

 #define FUNCTION_NAME	getgrgid

@@ -25,6 +26,9 @@

 #define ADD_VARIABLES	gid

 #define BUFLEN		NSS_BUFLEN_GROUP

+#define DEEPCOPY_FN	__copy_grp

+#define MERGE_FN	__merge_grp

+

 /* We are nscd, so we don't want to be talking to ourselves.  */

 #undef	USE_NSCD

--- glibc-2.17-c758a686/nscd/getgrnam_r.c

+++ glibc-2.17-c758a686/nscd/getgrnam_r.c

@@ -17,6 +17,7 @@

 #include <grp.h>

+#include <grp-merge.h>

 #define LOOKUP_TYPE	struct group

 #define FUNCTION_NAME	getgrnam

@@ -24,6 +25,9 @@

 #define ADD_PARAMS	const char *name

 #define ADD_VARIABLES	name

+#define DEEPCOPY_FN	__copy_grp

+#define MERGE_FN	__merge_grp

+

 /* We are nscd, so we don't want to be talking to ourselves.  */

 #undef	USE_NSCD

--- glibc-2.17-c758a686/nss/getXXbyYY_r.c

+++ glibc-2.17-c758a686/nss/getXXbyYY_r.c

@@ -131,6 +131,52 @@

 # define AF_VAL AF_INET

 #endif

+

+/* Set defaults for merge functions that haven't been defined.  */

+#ifndef DEEPCOPY_FN

+static inline int

+__copy_einval (LOOKUP_TYPE a,

+	       const size_t b,

+	       LOOKUP_TYPE *c,

+	       char *d,

+	       char **e)

+{

+  return EINVAL;

+}

+# define DEEPCOPY_FN __copy_einval

+#endif

+

+#ifndef MERGE_FN

+static inline int

+__merge_einval (LOOKUP_TYPE *a,

+		char *b,

+		char *c,

+		size_t d,

+		LOOKUP_TYPE *e,

+		char *f)

+{

+  return EINVAL;

+}

+# define MERGE_FN __merge_einval

+#endif

+

+#define CHECK_MERGE(err, status)		\

+  ({						\

+    do						\

+      {						\

+	if (err)				\

+	  {					\

+	    __set_errno (err);			\

+	    if (err == ERANGE)			\

+	      status = NSS_STATUS_TRYAGAIN;	\

+	    else				\

+	      status = NSS_STATUS_UNAVAIL;	\

+	    break;				\

+	  }					\

+      }						\

+    while (0);					\

+  })

+

 /* Type of the lookup function we need here.  */

 typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,

 					    size_t, int * H_ERRNO_PARM

@@ -152,13 +198,16 @@

   static service_user *startp;

   static lookup_function start_fct;

   service_user *nip;

+  int do_merge = 0;

+  LOOKUP_TYPE mergegrp;

+  char *mergebuf = NULL;

+  char *endptr = NULL;

   union

   {

     lookup_function l;

     void *ptr;

   } fct;

-

-  int no_more;

+  int no_more, err;

   enum nss_status status = NSS_STATUS_UNAVAIL;

 #ifdef USE_NSCD

   int nscd_status;

@@ -278,9 +327,66 @@

 	  && errno == ERANGE)

 	break;

+      if (do_merge)

+	{

+

+	  if (status == NSS_STATUS_SUCCESS)

+	    {

+	      /* The previous loop saved a buffer for merging.

+		 Perform the merge now.  */

+	      err = MERGE_FN (&mergegrp, mergebuf, endptr, buflen, resbuf,

+			      buffer);

+	      CHECK_MERGE (err,status);

+	      do_merge = 0;

+	    }

+	  else

+	    {

+	      /* If the result wasn't SUCCESS, copy the saved buffer back

+	         into the result buffer and set the status back to

+	         NSS_STATUS_SUCCESS to match the previous pass through the

+	         loop.

+	          * If the next action is CONTINUE, it will overwrite the value

+	            currently in the buffer and return the new value.

+	          * If the next action is RETURN, we'll return the previously-

+	            acquired values.

+	          * If the next action is MERGE, then it will be added to the

+	            buffer saved from the previous source.  */

+	      err = DEEPCOPY_FN (mergegrp, buflen, resbuf, buffer, NULL);

+	      CHECK_MERGE (err, status);

+	      status = NSS_STATUS_SUCCESS;

+	    }

+	}

+

+      /* If we were are configured to merge this value with the next one,

+         save the current value of the group struct.  */

+      if (nss_next_action (nip, status) == NSS_ACTION_MERGE

+	  && status == NSS_STATUS_SUCCESS)

+	{

+	  /* Copy the current values into a buffer to be merged with the next

+	     set of retrieved values.  */

+	  if (mergebuf == NULL)

+	    {

+	      /* Only allocate once and reuse it for as many merges as we need

+	         to perform.  */

+	      mergebuf = malloc (buflen);

+	      if (mergebuf == NULL)

+		{

+		  __set_errno (ENOMEM);

+		  status = NSS_STATUS_UNAVAIL;

+		  break;

+		}

+	    }

+

+	  err = DEEPCOPY_FN (*resbuf, buflen, &mergegrp, mergebuf, &endptr);

+	  CHECK_MERGE (err, status);

+	  do_merge = 1;

+	}

+

       no_more = __nss_next2 (&nip, REENTRANT_NAME_STRING,

 			     REENTRANT2_NAME_STRING, &fct.ptr, status, 0);

     }

+  free (mergebuf);

+  mergebuf = NULL;

 #ifdef HANDLE_DIGITS_DOTS

 done:

--- glibc-2.17-c758a686/nss/getnssent_r.c

+++ glibc-2.17-c758a686/nss/getnssent_r.c

@@ -79,7 +79,18 @@

       else

 	status = DL_CALL_FCT (fct.f, (0));

-      no_more = __nss_next2 (nip, func_name, NULL, &fct.ptr, status, 0);

+

+      /* This is a special-case.  When [SUCCESS=merge] is in play,

+         _nss_next2() will skip to the next database.  Due to the

+         implementation of that function, we can't know whether we're

+         in an enumeration or an individual lookup, which behaves

+         differently with regards to merging.  We'll treat SUCCESS as

+         an indication to start the enumeration at this database. */

+      if (nss_next_action (*nip, status) == NSS_ACTION_MERGE)

+	no_more = 1;

+      else

+	no_more = __nss_next2 (nip, func_name, NULL, &fct.ptr, status, 0);

+

       if (is_last_nip)

 	*last_nip = *nip;

     }

@@ -175,8 +186,18 @@

       do

 	{

-	  no_more = __nss_next2 (nip, getent_func_name, NULL, &fct.ptr,

-				 status, 0);

+        /* This is a special-case.  When [SUCCESS=merge] is in play,

+           _nss_next2() will skip to the next database.  Due to the

+           implementation of that function, we can't know whether we're

+           in an enumeration or an individual lookup, which behaves

+           differently with regards to merging.  We'll treat SUCCESS as

+           an indication to return the results here. */

+	  if (status == NSS_STATUS_SUCCESS

+	      && nss_next_action (*nip, status) == NSS_ACTION_MERGE)

+	    no_more = 1;

+	  else

+	    no_more = __nss_next2 (nip, getent_func_name, NULL, &fct.ptr,

+				   status, 0);

 	  if (is_last_nip)

 	    *last_nip = *nip;

--- glibc-2.17-c758a686/nss/nsswitch.c

+++ glibc-2.17-c758a686/nss/nsswitch.c

@@ -712,6 +712,9 @@

 	      else if (line - name == 8

 		       && __strncasecmp (name, "CONTINUE", 8) == 0)

 		action = NSS_ACTION_CONTINUE;

+	      else if (line - name == 5

+		       && __strncasecmp (name, "MERGE", 5) == 0)

+		action = NSS_ACTION_MERGE;

 	      else

 		goto finish;

--- glibc-2.17-c758a686/nss/nsswitch.h

+++ glibc-2.17-c758a686/nss/nsswitch.h

@@ -32,7 +32,8 @@

 typedef enum

 {

   NSS_ACTION_CONTINUE,

-  NSS_ACTION_RETURN

+  NSS_ACTION_RETURN,

+  NSS_ACTION_MERGE

 } lookup_actions;