[SSSD] [PATCH] Replace space: add some checks

Sumit Bose sbose at redhat.com
Mon Aug 25 16:27:01 UTC 2014


Hi,

this patch adds some additional checks to the logic or replacing space
with a different character. The idea is to not replace the space if we
might run into trouble with the modified name and log an error.

As mentioned in the commit message if the original name already contains
the replacement character the original name is used and if the input for
the revers operation contains both space and the replacement character
the input is returned unmodified as well. As an alternative it would be
possible to return NULL and cause an error during the lookup. I think
returning the unmodified name is more user friendly. The admin might
wonder why the space is not replaced but at least the name is resolved.

With this patch a name like 'abc def_ghi' is return unmodified if the
replacement character is '_' . But without the check 'abc_def_ghi' is
returned which cannot be resolved back which might cause more trouble
than the space in the name.

bye,
Sumit
-------------- next part --------------
From 2e2d8cdfbcbbadfe7fea632ab8151d77b0cdf464 Mon Sep 17 00:00:00 2001
From: Sumit Bose <sbose at redhat.com>
Date: Mon, 25 Aug 2014 10:36:46 +0200
Subject: [PATCH] Replace space: add some checks

This patch adds some additional checks if the option for replacing
spaces in user and group names is used.

When replacing space with the replacement character it is checked if the
name already contains the replacement character. If it does the
unmodified name is returned because in this case a revers operation
would not be possible.

For the reverse operation is it checked if the input contains both a
space and the replacement character. If this is true the unmodified name
is returned as well, because we have to assume that it is the original
name because otherwise it wouldn't contain both characters.

Additionally a shortcut if the replacement characters is a space and
tests for the new checks are added. The man page is updated accordingly.

Related to https://fedorahosted.org/sssd/ticket/1854 and
https://fedorahosted.org/sssd/ticket/2397 .
---
 src/man/sssd.conf.5.xml              |  8 +++++---
 src/tests/cmocka/test_string_utils.c |  4 ++++
 src/util/string_utils.c              | 22 +++++++++++++++++++---
 src/util/util.h                      |  2 +-
 4 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/src/man/sssd.conf.5.xml b/src/man/sssd.conf.5.xml
index 81a46ed..ad01f37 100644
--- a/src/man/sssd.conf.5.xml
+++ b/src/man/sssd.conf.5.xml
@@ -334,9 +334,11 @@
                             </para>
                             <para>
                                 Please note it is a configuration error to use
-                                a replacement character that might be used by
-                                another LDAP object. In that case, result of
-                                a lookup is undefined.
+                                a replacement character that might be used in
+                                user or group names. If a name contains the
+                                replacement character SSSD tries to return the
+                                unmodified name but in general the result of a
+                                lookup is undefined.
                             </para>
                             <para>
                                 Default: not set (spaces will not be replaced)
diff --git a/src/tests/cmocka/test_string_utils.c b/src/tests/cmocka/test_string_utils.c
index 93d7d71..e446387 100644
--- a/src/tests/cmocka/test_string_utils.c
+++ b/src/tests/cmocka/test_string_utils.c
@@ -47,6 +47,7 @@ void test_replace_whitespaces(void **state)
         { "    ", "    ", ' ' },
         { "abcd", "abcd", ' ' },
         { "a b c d", "a b c d", ' ' },
+        { "a b^c d", "a b^c d", '^' },
         { NULL, NULL, '\0' },
     };
 
@@ -92,6 +93,8 @@ void test_reverse_replace_whitespaces(void **state)
         { "abcd", "abcd", '-' },
         { "a-b-c-d", "a b c d", '-' },
         { "-a-b-c-d-", " a b c d ", '-' },
+        { "a b c d", "a b c d", '-' },
+        { " a b c d ", " a b c d ", '-' },
         { "^", " ", '^' },
         { "^^^^", "    ", '^' },
         { "abcd", "abcd", '^' },
@@ -102,6 +105,7 @@ void test_reverse_replace_whitespaces(void **state)
         { "abcd", "abcd", ' ' },
         { "a b c d", "a b c d", ' ' },
         { " a b c d ", " a b c d ", ' ' },
+        { "a b^c d", "a b^c d", '^' },
         { NULL, NULL, '\0' },
     };
 
diff --git a/src/util/string_utils.c b/src/util/string_utils.c
index ec4cc68..6a161b0 100644
--- a/src/util/string_utils.c
+++ b/src/util/string_utils.c
@@ -48,18 +48,34 @@ char * sss_replace_space(TALLOC_CTX *mem_ctx,
                          const char *orig_name,
                          const char subst)
 {
-    if (subst == '\0') {
+    if (subst == '\0' || subst == ' ') {
         return talloc_strdup(mem_ctx, orig_name);
     }
+
+    if (strchr(orig_name, subst) != NULL) {
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              "Input [%s] already contains replacement character [%c].\n",
+              orig_name, subst);
+        return talloc_strdup(mem_ctx, orig_name);
+    }
+
     return replace_char(mem_ctx, orig_name, ' ', subst);
 }
 
 char * sss_reverse_replace_space(TALLOC_CTX *mem_ctx,
-                                 char *orig_name,
+                                 const char *orig_name,
                                  const char subst)
 {
-    if (subst == '\0') {
+    if (subst == '\0' || subst == ' ') {
         return talloc_strdup(mem_ctx, orig_name);
     }
+
+    if (strchr(orig_name, subst) != NULL && strchr(orig_name, ' ') != NULL) {
+        DEBUG(SSSDBG_TRACE_FUNC,
+              "Input [%s] contains replacement character [%c] and space.\n",
+              orig_name, subst);
+        return talloc_strdup(mem_ctx, orig_name);
+    }
+
     return replace_char(mem_ctx, orig_name, subst, ' ');
 }
diff --git a/src/util/util.h b/src/util/util.h
index ca740d0..d3b746b 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -570,7 +570,7 @@ char * sss_replace_space(TALLOC_CTX *mem_ctx,
                          const char *orig_name,
                          const char replace_char);
 char * sss_reverse_replace_space(TALLOC_CTX *mem_ctx,
-                                 char *orig_name,
+                                 const char *orig_name,
                                  const char replace_char);
 
 #endif /* __SSSD_UTIL_H__ */
-- 
1.8.3.1



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