[SSSD] [sssd][patch] SYSDB: sysdb_getnetgr returns ENOENT

Lukas Slebodnik lslebodn at redhat.com
Tue Jun 24 14:18:15 UTC 2014


On (24/06/14 13:33), Pavel Reichl wrote:
>On Mon, 2014-06-23 at 13:50 +0200, Jakub Hrozek wrote:
>> On Thu, Jun 19, 2014 at 05:53:37PM +0200, Pavel Reichl wrote:
>> > From 6e2af6d696fd0e731467c50dbb715756a4bcb0a3 Mon Sep 17 00:00:00 2001
>> > From: Pavel Reichl <preichl at redhat.com>
>> > Date: Tue, 27 May 2014 19:11:20 +0100
>> > Subject: [PATCH 1/4] SYSDB: sss_ldb_search - wrapper around ldb_search
>> > 
>> > Make sure that if no results were found ENOENT is returned rather than just
>> > empty list of results.
>> > 
>> > Resolves:
>> > https://fedorahosted.org/sssd/ticket/1991
>> > ---
>> >  src/db/sysdb.h     |  5 +++++
>> >  src/db/sysdb_ops.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
>> >  2 files changed, 52 insertions(+)
>> > 
>> > diff --git a/src/db/sysdb.h b/src/db/sysdb.h
>> > index dd14190bfa156c6b2842e2af81d7b58efa3ea06f..634df049421586959531d8d1a365a2d50d15d1a6 100644
>> > --- a/src/db/sysdb.h
>> > +++ b/src/db/sysdb.h
>> > @@ -480,6 +480,11 @@ int sysdb_get_netgroup_attr(TALLOC_CTX *mem_ctx,
>> >                              const char **attributes,
>> >                              struct ldb_result **res);
>> >  
>> > +errno_t sss_ldb_search(struct ldb_context *ldb, TALLOC_CTX *mem_ctx,
>> > +                       struct ldb_result **_result, struct ldb_dn *base,
>> > +                       enum ldb_scope scope, const char * const *attrs,
>> > +                       const char *exp_fmt, ...);
>> 
>> You need to use SSS_ATTRIBUTE_PRINTF here.
>
>OK, but it didn't like "" being passed as fmt causing:
>-Werror=format-zero-length. 
>
>To avoid this warning, NULL is passed instead of "". sss_ldb_search now
>handles explicitly case when fmt is NULL because no filter processing is
>required then.
>
And null caused warning in static analysers :-)

Error: PW.NON_CONST_PRINTF_FORMAT_STRING:
sssd-1.11.92/src/db/sysdb_ops.c:109: non_const_printf_format_string: format string is not a string literal, potential security vulnerability if user controlled
sssd-1.11.92/src/db/sysdb_ops.c:109: caretline:

I prefer to avoid compiler warnings. It will be better to use NULL.



>From: Pavel Reichl <preichl at redhat.com>
>Date: Tue, 27 May 2014 19:11:20 +0100
>Subject: [PATCH 1/5] SYSDB: sss_ldb_search - wrapper around ldb_search
>
>Make sure that if no results were found ENOENT is returned rather than just
>empty list of results.
>
>Resolves:
>https://fedorahosted.org/sssd/ticket/1991
>---
> src/db/sysdb.h     |  5 +++++
> src/db/sysdb_ops.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 55 insertions(+)
>
>diff --git a/src/db/sysdb.h b/src/db/sysdb.h
>index 911430eefcbf520ca04f123a3b6f1882dc25876b..17cd5110c9bdafd8d7b18e621188523ed41e5c8a 100644
>--- a/src/db/sysdb.h
>+++ b/src/db/sysdb.h
>@@ -481,6 +481,11 @@ int sysdb_get_netgroup_attr(TALLOC_CTX *mem_ctx,
>                             const char **attributes,
>                             struct ldb_result **res);
> 
>+errno_t sss_ldb_search(struct ldb_context *ldb, TALLOC_CTX *mem_ctx,
>+                       struct ldb_result **_result, struct ldb_dn *base,
>+                       enum ldb_scope scope, const char * const *attrs,
>+                       const char *exp_fmt, ...) SSS_ATTRIBUTE_PRINTF(7, 8);
>+
> /* functions that modify the databse
>  * they have to be called within a transaction
>  * See sysdb_transaction_send()/_recv() */
>diff --git a/src/db/sysdb_ops.c b/src/db/sysdb_ops.c
>index 4d31cb6a0e83370a2c49a666f9474d93baf430b0..25fccc5fdacd85416268e02632826fd87174e7f7 100644
>--- a/src/db/sysdb_ops.c
>+++ b/src/db/sysdb_ops.c
>@@ -74,6 +74,56 @@ static uint32_t get_attr_as_uint32(struct ldb_message *msg, const char *attr)
>     return l;
> }
> 
>+
>+/* Wrapper around ldb_search to ensure that if zero results are found then
>+ * ENOENT is returned
>+ */
>+errno_t sss_ldb_search(struct ldb_context *ldb, TALLOC_CTX *mem_ctx,
>+                       struct ldb_result **_result, struct ldb_dn *base,
>+                       enum ldb_scope scope, const char * const *attrs,
>+                       const char *exp_fmt, ...)
>+{
>+    char *s;
>+    int lret;
>+    va_list ap;
>+    errno_t ret;
>+    TALLOC_CTX *tmp_ctx = NULL;
>+
>+    if (exp_fmt != NULL) {
>+        tmp_ctx = talloc_new(NULL);
>+        if (tmp_ctx == NULL) {
>+            ret = ENOMEM;
>+            goto done;
>+        }
>+
>+        va_start(ap, exp_fmt);
>+        s = talloc_vasprintf(tmp_ctx, exp_fmt, ap);
>+        if (s == NULL) {
>+            DEBUG(SSSDBG_MINOR_FAILURE, "Failed to process filter.\n");
>+            ret = ENOMEM;
>+            goto done;
va_end is not called in this case.
It will be better to move va_end before if condition.

>+        }
>+        va_end(ap);
>+        lret = ldb_search(ldb, mem_ctx, _result, base, scope, attrs, "%s", s);
>+    } else {
>+        lret = ldb_search(ldb, mem_ctx, _result, base, scope, attrs, NULL);
>+    }
>+
>+    ret = sysdb_error_to_errno(lret);
>+    if (ret != EOK) {
>+        goto done;
>+    }
>+
>+    if ((*_result)->count == 0) {
>+        ret = ENOENT;
>+        goto done;
>+    }
>+
>+done:
>+    talloc_free(tmp_ctx);
>+    return ret;
>+}
>+
> /*
>  * The wrapper around ldb_modify that uses LDB_CONTROL_PERMISSIVE_MODIFY_OID
>  * so that on adds entries that already exist are skipped and similarly
>-- 
>1.8.4.2
>

>From cd9f7ed48017516d01c79d59af6af63d87a4a31f Mon Sep 17 00:00:00 2001
>From: Pavel Reichl <preichl at redhat.com>
>Date: Thu, 19 Jun 2014 15:38:59 +0100
>Subject: [PATCH 2/5] TESTS: add tests for sss_ldb_search
>
>Resolves:
>https://fedorahosted.org/sssd/ticket/1991
>---
> src/tests/sysdb-tests.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 97 insertions(+)
>
>diff --git a/src/tests/sysdb-tests.c b/src/tests/sysdb-tests.c
>index ac78f368f04b5138eecb6b121b43ac45bc3c32a3..650219d266ca052d941343321608fadf3c76872d 100644
>--- a/src/tests/sysdb-tests.c
>+++ b/src/tests/sysdb-tests.c
>@@ -3979,6 +3979,87 @@ START_TEST(test_odd_characters)
> }
> END_TEST
> 
>+START_TEST(test_sss_ldb_search)
>+{
>+    errno_t ret;
>+    struct sysdb_test_ctx *test_ctx;
>+    struct ldb_dn *group_dn, *nonexist_dn;
>+    struct ldb_result *res;
>+    const char groupname[] = "test_group";
>+    const char *received_group;
>+
>+    /* Setup */
>+    ret = setup_sysdb_tests(&test_ctx);
>+    if (ret != EOK) {
>+        fail("Could not set up the test");
>+        return;
>+    }
>+
>+    check_leaks_push(test_ctx);
>+
>+    group_dn = sysdb_group_dn(test_ctx, test_ctx->domain, groupname);
>+    fail_if(group_dn == NULL, "sysdb_group_dn failed");
>+
>+    nonexist_dn = sysdb_group_dn(test_ctx, test_ctx->domain,
>+                                 "non-existing-group");
>+    fail_if(nonexist_dn == NULL, "sysdb_group_dn failed");
>+
>+    /* Add */
>+    ret = sysdb_add_incomplete_group(test_ctx->domain,
>+                                     groupname, 20000, NULL, NULL, true, 0);
>+    fail_unless(ret == EOK, "sysdb_add_incomplete_group error [%d][%s]",
>+                ret, strerror(ret));
>+
>+    /* Retrieve */
>+
>+    /* Empty filter */
>+    ret = sss_ldb_search(test_ctx->sysdb->ldb, test_ctx, &res, group_dn,
>+                         LDB_SCOPE_BASE, NULL, NULL);
>+
>+    fail_unless(ret == EOK, "sss_ldb_search error [%d][%s]",
>+                ret, strerror(ret));
>+
>+    fail_unless(res->count == 1, "Received [%d] responses",
>+                                 res->count);
>+
>+    received_group = ldb_msg_find_attr_as_string(res->msgs[0], SYSDB_NAME,
>+                                                 NULL);
>+    fail_unless(strcmp(received_group, groupname) == 0,
>+                "Expected [%s], got [%s]", groupname, received_group);
>+
>+    talloc_zfree(res);
>+
>+    /* Non-empty filter */
>+    ret = sss_ldb_search(test_ctx->sysdb->ldb, test_ctx, &res, group_dn,
>+                         LDB_SCOPE_BASE, NULL, "objectClass=group");
>+
>+    fail_unless(ret == EOK, "sss_ldb_search error [%d][%s]",
>+                ret, strerror(ret));
>+    talloc_zfree(res);
>+
>+    /* Filter yeilding no results */
>+    ret = sss_ldb_search(test_ctx->sysdb->ldb, test_ctx, &res, group_dn,
>+                         LDB_SCOPE_BASE, NULL,
>+                         "objectClass=nonExistingObjectClass");
>+
>+    fail_unless(ret == ENOENT, "sss_ldb_search error [%d][%s]",
>+                ret, strerror(ret));
>+    talloc_zfree(res);
>+
>+    /* Non-existing dn */
>+    ret = sss_ldb_search(test_ctx->sysdb->ldb, test_ctx, &res, nonexist_dn,
>+                         LDB_SCOPE_BASE, NULL, NULL);
>+
>+    fail_unless(ret == ENOENT, "sss_ldb_search error [%d][%s]",
>+                ret, strerror(ret));
>+    talloc_zfree(res);
>+
>+    talloc_zfree(nonexist_dn);
>+    talloc_zfree(group_dn);
>+    fail_unless(check_leaks_pop(test_ctx) == true, "Memory leak");
>+}
>+END_TEST
>+
> /* == SERVICE TESTS == */
> void services_check_match(struct sysdb_test_ctx *test_ctx,
>                           bool by_name,
>@@ -4539,6 +4620,18 @@ START_TEST (test_sysdb_search_return_ENOENT)
>     talloc_zfree(msgs);
>     talloc_zfree(user_dn);
> 
>+    /* sss_ldb_search */
>+    user_dn = sysdb_user_dn(test_ctx, test_ctx->domain, "nonexisting_user");
>+    fail_if(user_dn == NULL, "sysdb_user_dn failed");
>+    ret = sss_ldb_search(test_ctx->sysdb->ldb, test_ctx, &res, user_dn,
>+                         LDB_SCOPE_BASE, NULL, "objectClass=user");
>+
>+    fail_unless(ret == ENOENT, "sss_ldb_search failed: %d, %s",
>+                               ret, strerror(ret));
>+
>+    talloc_zfree(res);
>+    talloc_zfree(user_dn);
>+
>     /* TODO: test sysdb_search_selinux_config */
> 
>     fail_unless(check_leaks_pop(test_ctx) == true, "Memory leak");
>@@ -5786,6 +5879,10 @@ Suite *create_sysdb_suite(void)
>                         MBO_GROUP_BASE , MBO_GROUP_BASE + 10);
>     tcase_add_loop_test(tc_memberof, test_sysdb_memberof_check_nested_double_ghosts,
>                         MBO_GROUP_BASE , MBO_GROUP_BASE + 10);
>+
>+    /* sss_ldb_search */
>+    tcase_add_test(tc_sysdb, test_sss_ldb_search);
>+
>     /* This loop counts backwards so the indexing is a little odd */
>     tcase_add_loop_test(tc_memberof, test_sysdb_memberof_mod_replace_keep,
>                         1 , 11);
>-- 
>1.8.4.2
>

>From 7954ad8ee3310d7e7bc9ac12c3b764786c052a4d Mon Sep 17 00:00:00 2001
>From: Pavel Reichl <preichl at redhat.com>
>Date: Wed, 26 Feb 2014 16:52:26 +0000
>Subject: [PATCH 3/5] SYSDB: sysdb_getnetgr returns ENOENT
>
>Replace call of ldb_search by sss_ldb_search to make sure that ENOENT is
>returned if no results were found.
>
>Resolves:
>https://fedorahosted.org/sssd/ticket/1991
>---
> src/db/sysdb_search.c | 20 ++++++++------------
> 1 file changed, 8 insertions(+), 12 deletions(-)
>
>diff --git a/src/db/sysdb_search.c b/src/db/sysdb_search.c
>index 60ad61368d92d12bca3833bc08b0673c581ab882..608277ab34c3280659cb2cf04ea57721bd9790f5 100644
>--- a/src/db/sysdb_search.c
>+++ b/src/db/sysdb_search.c
>@@ -786,7 +786,6 @@ errno_t sysdb_getnetgr(TALLOC_CTX *mem_ctx,
>     char *sanitized_netgroup;
>     char *lc_sanitized_netgroup;
>     char *netgroup_dn;
>-    int lret;
>     errno_t ret;
> 
>     tmp_ctx = talloc_new(NULL);
>@@ -816,18 +815,15 @@ errno_t sysdb_getnetgr(TALLOC_CTX *mem_ctx,
>         goto done;
>     }
> 
>-    lret = ldb_search(domain->sysdb->ldb, tmp_ctx, &result, base_dn,
>-                     LDB_SCOPE_SUBTREE, attrs,
>-                     SYSDB_NETGR_TRIPLES_FILTER, lc_sanitized_netgroup,
>-                     sanitized_netgroup, sanitized_netgroup,
>-                     netgroup_dn);
>-    ret = sysdb_error_to_errno(lret);
>-    if (ret != EOK) {
>-        goto done;
>-    }
>+    ret = sss_ldb_search(domain->sysdb->ldb, tmp_ctx, &result, base_dn,
>+                         LDB_SCOPE_SUBTREE, attrs,
>+                         SYSDB_NETGR_TRIPLES_FILTER, lc_sanitized_netgroup,
>+                         sanitized_netgroup, sanitized_netgroup,
>+                         netgroup_dn);
> 
>-    *res = talloc_steal(mem_ctx, result);
>-    ret = EOK;
>+    if (ret == EOK || ret == ENOENT) {
>+        *res = talloc_steal(mem_ctx, result);
There is a warning from coverity
Error: UNINIT (CWE-457):
sssd-1.11.92/src/db/sysdb_search.c:785: var_decl: Declaring variable "result" without initializer.
sssd-1.11.92/src/db/sysdb_search.c:825: uninit_use_in_call: Using uninitialized value "result" when calling "_talloc_steal_loc".

I think it is false positive.

>+    }
> 
> done:
>     talloc_zfree(tmp_ctx);
>-- 
>1.8.4.2
>

>From 94a3501fa6d0f238c889e2e05858c0a42579815d Mon Sep 17 00:00:00 2001
>From: Pavel Reichl <preichl at redhat.com>
>Date: Thu, 19 Jun 2014 16:18:12 +0100
>Subject: [PATCH 4/5] TESTS: sysdb_getnetgr - return ENOENT
>
>Resolves:
>https://fedorahosted.org/sssd/ticket/1991
>---
BTW 3rd and 4th patch are small.

I am used to sending a fix and an unit test in single patch. Small benefit is
that we don't forgot to backport a test. I don't have strong preferences.
I just want to start discussion what should be prefered way
    a) to send a fix and an unit test in two patches
    b) to send a fix and an unit test in single patch
(of course there can be exceptions :-)

>From 44c4d576c840c01bade8f7f7aa6c980793d79505 Mon Sep 17 00:00:00 2001
>From: Pavel Reichl <preichl at redhat.com>
>Date: Tue, 24 Jun 2014 09:47:09 +0100
>Subject: [PATCH 5/5] NSS: lookup_netgr_step don't access result on ENOENT
>
>Don't access result if return value is not EOK.
>---
> src/responder/nss/nsssrv_netgroup.c | 45 +++++++++++++++++++------------------
> 1 file changed, 23 insertions(+), 22 deletions(-)
>
>diff --git a/src/responder/nss/nsssrv_netgroup.c b/src/responder/nss/nsssrv_netgroup.c
>index 1c9b72ae30c6ef1115d1ed972a12dc554db04bbe..d60f72a743157066dffca86493dfebf40bb451f6 100644
>--- a/src/responder/nss/nsssrv_netgroup.c
>+++ b/src/responder/nss/nsssrv_netgroup.c
>@@ -514,30 +514,31 @@ static errno_t lookup_netgr_step(struct setent_step_ctx *step_ctx)
> 
>         /* Look up the netgroup in the cache */
>         ret = sysdb_getnetgr(step_ctx->dctx, dom, name, &step_ctx->dctx->res);
>-        if (ret == ENOENT) {
>-            /* This netgroup was not found in this domain */
>-            if (!step_ctx->dctx->check_provider) {
>-                if (step_ctx->check_next) {
>-                    dom = get_next_domain(dom, false);
>-                    continue;
>+        if (ret == EOK) {
>+            if (step_ctx->dctx->res->count > 1) {
>+                DEBUG(SSSDBG_FATAL_FAILURE,
>+                      "getnetgr call returned more than one result !?!\n");
>+                ret = EMSGSIZE;
>+                goto done;
>+            }
>+        } else {
>+            if (ret == ENOENT) {
>+                /* This netgroup was not found in this domain */
>+                if (!step_ctx->dctx->check_provider) {
>+                    if (step_ctx->check_next) {
>+                        dom = get_next_domain(dom, false);
>+                        continue;
>+                    } else {
>+                        break;
>+                    }
>                 }
>-                else break;
>+                ret = EOK;
                  warning: Value stored to 'ret' is never read
I think conditionc could be more flatten
if (ret == EOK) {
...
} else if (ret == ENOENT) {
...
} else {
...
}

Or switch/case/default.

LS



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