sysdb: try dealing with binary-content attributes

https://fedorahosted.org/sssd/ticket/1818

I have here a LDAP user entry which has this attribute

	loginAllowedTimeMap::
	 AAAAAAAAAP///38AAP///38AAP///38AAP///38AAP///38AAAAAAAAA

In the function sysdb_attrs_add_string(), called from
sdap_attrs_add_ldap_attr(), strlen() is called on this blob, which is
the wrong thing to do. The result of strlen is then used to populate
the .v_length member of a struct ldb_val - and this will set it to
zero in this case. (There is also the problem that there may not be
a '\0' at all in the blob.)

Subsequently, .v_length being 0 makes ldb_modify(), called from
sysdb_set_entry_attr(), return LDB_ERR_INVALID_ATTRIBUTE_SYNTAX. End
result is that users do not get stored in the sysdb, and programs like
`id` or `getent ...` show incomplete information.

The bug was encountered with sssd-1.8.5. sssd-1.5.11 seemed to behave
fine, but that may not mean that is the absolute lower boundary of
introduction of the problem.

2 files changed, 12 insertions, 0 deletions

diff --git a/src/db/sysdb.c b/src/db/sysdb.c
index e7524f4b..7c347912 100644
--- a/src/db/sysdb.c
+++ b/src/db/sysdb.c
@@ -512,6 +512,16 @@ int sysdb_attrs_add_string(struct sysdb_attrs *attrs,
     return sysdb_attrs_add_val(attrs, name, &v);
 }
 
+int sysdb_attrs_add_mem(struct sysdb_attrs *attrs, const char *name,
+                        const void *mem, size_t size)
+{
+	struct ldb_val v;
+
+	v.data   = discard_const(mem);
+	v.length = size;
+	return sysdb_attrs_add_val(attrs, name, &v);
+}
+
 int sysdb_attrs_add_bool(struct sysdb_attrs *attrs,
                          const char *name, bool value)
 {
diff --git a/src/db/sysdb.h b/src/db/sysdb.h
index fff97a8a..23cbbb0d 100644
--- a/src/db/sysdb.h
+++ b/src/db/sysdb.h
@@ -250,6 +250,8 @@ int sysdb_attrs_add_val(struct sysdb_attrs *attrs,
                         const char *name, const struct ldb_val *val);
 int sysdb_attrs_add_string(struct sysdb_attrs *attrs,
                            const char *name, const char *str);
+int sysdb_attrs_add_mem(struct sysdb_attrs *, const char *,
+                        const void *, size_t);
 int sysdb_attrs_add_bool(struct sysdb_attrs *attrs,
                          const char *name, bool value);
 int sysdb_attrs_add_long(struct sysdb_attrs *attrs,