Relevant BUGIDs: 490938

Purpose of commit: new feature

Commit summary:
---------------
Added libpammodutil and link it with every module as its built.
The issue here is that there is a lot of code that the various modules
use in common, and this staic library can be used to help make this code
more maintainable. I do not intend to make this library dynamic. Especially
right now, as I want to be free to chop and change the API and don't want
to deal with revision control and third party modules.

This checkin makes the pam_rhost_auth module make some use of this new
library. I don't intend to add support for any other module prior to
releasing 0.76.

7 files changed, 299 insertions, 0 deletions

diff --git a/modules/pammodutil/Makefile b/modules/pammodutil/Makefile
new file mode 100644
index 00000000..a97388ef
--- /dev/null
+++ b/modules/pammodutil/Makefile
@@ -0,0 +1,53 @@
+#
+# $Id$
+#
+#
+
+include ../../Make.Rules
+
+LIBNAME=libpammodutil
+
+# ---------------------------------------------
+
+dummy: all
+
+# ---------------------------------------------
+
+CFLAGS += $(PIC) $(STATIC) $(MOREFLAGS) \
+  -DLIBPAM_VERSION_MAJOR=$(MAJOR_REL) \
+  -DLIBPAM_VERSION_MINOR=$(MINOR_REL)
+
+# all the object files we care about
+LIBOBJECTS = modutil_cleanup.o modutil_getpwnam.o modutil_getpwuid.o
+
+# static library name
+LIBSTATIC = $(LIBNAME).a
+
+SLIBOBJECTS = $(addprefix static/,$(LIBOBJECTS) $(STATICOBJ))
+
+# ---------------------------------------------
+## rules
+
+all: dirs $(LIBSTATIC) ../../Make.Rules
+
+dirs:
+	$(MKDIR) static
+
+static/%.o : %.c
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c $< -o $@
+
+$(LIBSTATIC): $(SLIBOBJECTS)
+	ar cr $@ $(SLIBOBJECTS)
+	$(RANLIB) $@
+
+install:
+	@echo "at this time, we're not installing $(LIBSTATIC)"
+
+remove:
+	@echo "at this time, there is nothing to remove"
+
+clean:
+	rm -f a.out core *~ static/*.o
+	rm -f *.a *.o
+	if [ -d dynamic ]; then rmdir dynamic ; fi
+	if [ -d static ]; then rmdir static ; fi
diff --git a/modules/pammodutil/README b/modules/pammodutil/README
new file mode 100644
index 00000000..241f83a7
--- /dev/null
+++ b/modules/pammodutil/README
@@ -0,0 +1,15 @@
+$Id$
+
+This is a libarary of routines for use by modules. The routines seem
+to have a common use for modules, but are not part of libpam and never
+will be. They are also a convenient layer of abstraction for providing
+thread-safe functions that may require use of pam_handle_t 'data'
+items to make their thread-safeness tied to the use of a single
+pam_handle_t per thread.
+
+Functions provided so far are all listed in
+
+   include/security/_pam_modutil.h
+
+.
+
diff --git a/modules/pammodutil/include/security/_pam_modutil.h b/modules/pammodutil/include/security/_pam_modutil.h
new file mode 100644
index 00000000..af8a7ae1
--- /dev/null
+++ b/modules/pammodutil/include/security/_pam_modutil.h
@@ -0,0 +1,33 @@
+#ifndef _PAM_MODUTIL_H
+#define _PAM_MODUTIL_H
+
+/*
+ * $Id$
+ *
+ * This file is a list of handy libc wrappers that attempt to provide some
+ * thread-safe and other convenient functionality to modules in a form that
+ * is common, but not dynamically linked with yet another dynamic pam
+ * library extension.
+ *
+ * A number of these functions reserve space in a pam_[sg]et_data item.
+ * In all cases, the name of the item is prefixed with "_pammodutil_*".
+ *
+ * On systems that simply can't support thread safe programming, these
+ * functions don't support it either - sorry.
+ *
+ * Copyright (c) 2001 Andrew Morgan <morgan@kernel.org>
+ */
+
+#include <pwd.h>
+#include <sys/types.h>
+
+extern struct passwd *_pammodutil_getpwnam(pam_handle_t *pamh,
+					   const char *user);
+
+extern struct passwd *_pammodutil_getpwuid(pam_handle_t *pamh,
+					   uid_t uid);
+
+extern void _pammodutil_cleanup(pam_handle_t *pamh, void *data,
+				int error_status);
+
+#endif /* _PAM_MODUTIL_H */
diff --git a/modules/pammodutil/modutil_cleanup.c b/modules/pammodutil/modutil_cleanup.c
new file mode 100644
index 00000000..e95d6100
--- /dev/null
+++ b/modules/pammodutil/modutil_cleanup.c
@@ -0,0 +1,16 @@
+/*
+ * $Id$
+ *
+ * This function provides a common pam_set_data() friendly version of free().
+ */
+
+#include "pammodutil.h"
+
+void _pammodutil_cleanup(pam_handle_t *pamh, void *data, int error_status)
+{
+    if (data) {
+	/* junk it */
+	(void) free(data);
+    }
+}
+
diff --git a/modules/pammodutil/modutil_getpwnam.c b/modules/pammodutil/modutil_getpwnam.c
new file mode 100644
index 00000000..287dc065
--- /dev/null
+++ b/modules/pammodutil/modutil_getpwnam.c
@@ -0,0 +1,80 @@
+/*
+ * $Id$
+ *
+ * This function provides a thread safer version of getpwnam() for use
+ * with PAM modules that care about this sort of thing.
+ *
+ * XXX - or at least it should provide a thread-safe alternative.
+ */
+
+#include "pammodutil.h"
+
+#include <pwd.h>
+#include <stdlib.h>
+
+struct passwd *_pammodutil_getpwnam(pam_handle_t *pamh, const char *user)
+{
+#ifdef HAVE_GETPWNAM_R
+
+    void *buffer=NULL;
+    size_t length = PWD_INITIAL_LENGTH;
+
+    do {
+	int status;
+	void *new_buffer;
+	struct passwd *result = NULL;
+
+	new_buffer = realloc(buffer, sizeof(struct passwd) + length);
+	if (new_buffer == NULL) {
+
+	    D(("out of memory"));
+
+	    /* no memory for the user - so delete the memory */
+	    if (buffer) {
+		free(buffer);
+	    }
+	    return NULL;
+	}
+	buffer = new_buffer;
+
+	/* make the re-entrant call to get the pwd structure */
+	status = getpwnam_r(user, buffer,
+			    sizeof(struct passwd) + (char *) buffer,
+			    length, &result);
+	if (!status && result) {
+	    status = pam_set_data(pamh, "_pammodutil_getpwnam", result,
+				  _pammodutil_cleanup);
+	    if (status == PAM_SUCCESS) {
+		D(("success"));
+		return result;
+	    }
+
+	    D(("was unable to register the data item [%s]",
+	       pam_strerror(pamh, status)));
+
+	    free(buffer);
+	    return NULL;
+
+	}
+	
+	length <<= 1;
+
+    } while (length < PWD_ABSURD_PWD_LENGTH);
+
+    D(("pwd structure took %u bytes or so of memory",
+       length+sizeof(struct passwd)));
+
+    free(buffer);
+    return NULL;
+
+#else /* ie. ifndef HAVE_GETPWNAM_R */
+
+    /*
+     * Sorry, there does not appear to be a reentrant version of
+     * getpwnam(). So, we use the standard libc function.
+     */
+    
+    return getpwnam(user);
+
+#endif /* def HAVE_GETPWNAM_R */
+}
diff --git a/modules/pammodutil/modutil_getpwuid.c b/modules/pammodutil/modutil_getpwuid.c
new file mode 100644
index 00000000..e200dd1e
--- /dev/null
+++ b/modules/pammodutil/modutil_getpwuid.c
@@ -0,0 +1,80 @@
+/*
+ * $Id$
+ *
+ * This function provides a thread safer version of getpwuid() for use
+ * with PAM modules that care about this sort of thing.
+ *
+ * XXX - or at least it should provide a thread-safe alternative.
+ */
+
+#include "pammodutil.h"
+
+#include <pwd.h>
+#include <stdlib.h>
+
+struct passwd *_pammodutil_getpwuid(pam_handle_t *pamh, uid_t uid)
+{
+#ifdef HAVE_GETPWNAM_R
+
+    void *buffer=NULL;
+    size_t length = PWD_INITIAL_LENGTH;
+
+    do {
+	int status;
+	void *new_buffer;
+	struct passwd *result = NULL;
+
+	new_buffer = realloc(buffer, sizeof(struct passwd) + length);
+	if (new_buffer == NULL) {
+
+	    D(("out of memory"));
+
+	    /* no memory for the user - so delete the memory */
+	    if (buffer) {
+		free(buffer);
+	    }
+	    return NULL;
+	}
+	buffer = new_buffer;
+
+	/* make the re-entrant call to get the pwd structure */
+	status = getpwuid_r(uid, buffer,
+			    sizeof(struct passwd) + (char *) buffer,
+			    length, &result);
+	if (!status && result) {
+	    status = pam_set_data(pamh, "_pammodutil_getpwuid", result,
+				  _pammodutil_cleanup);
+	    if (status == PAM_SUCCESS) {
+		D(("success"));
+		return result;
+	    }
+
+	    D(("was unable to register the data item [%s]",
+	       pam_strerror(pamh, status)));
+
+	    free(buffer);
+	    return NULL;
+
+	}
+	
+	length <<= 1;
+
+    } while (length < PWD_ABSURD_PWD_LENGTH);
+
+    D(("pwd structure took %u bytes or so of memory",
+       length+sizeof(struct passwd)));
+
+    free(buffer);
+    return NULL;
+
+#else /* ie. ifndef HAVE_GETPWNAM_R */
+
+    /*
+     * Sorry, there does not appear to be a reentrant version of
+     * getpwnam(). So, we use the standard libc function.
+     */
+    
+    return getpwuid(uid);
+
+#endif /* def HAVE_GETPWNAM_R */
+}
diff --git a/modules/pammodutil/pammodutil.h b/modules/pammodutil/pammodutil.h
new file mode 100644
index 00000000..efcc98e1
--- /dev/null
+++ b/modules/pammodutil/pammodutil.h
@@ -0,0 +1,22 @@
+#ifndef PAMMODUTIL_H
+#define PAMMODUTIL_H
+
+/*
+ * $Id$
+ *
+ * Copyright (c) 2001 Andrew Morgan <morgan@kernel.org>
+ */
+
+#include <security/_pam_aconf.h>
+#include <security/_pam_macros.h>
+#include <security/pam_modules.h>
+#include <security/_pam_modutil.h>
+
+#define PWD_INITIAL_LENGTH     0x100
+#define PWD_ABSURD_PWD_LENGTH  0x1000
+
+/* This is a simple cleanup, it just free()s the 'data' memory */
+extern void _pammodutil_cleanup(pam_handle_t *pamh, void *data,
+				int error_status);
+
+#endif /* PAMMODUTIL_H */