Account: Race conditions fixes (like: bz#1061150)

This patch solves:
    * Avoid race conditions with shadow-utils.
    * Avoid race condition with libuser: uid/gid "sharing" amoung users/groups.
    * Fix deadlock in lock.c code.

This patch introduces giant lock which is held for all write operations.

1 files changed, 30 insertions, 5 deletions

diff --git a/src/account/LMI_AccountManagementServiceProvider.c b/src/account/LMI_AccountManagementServiceProvider.c
index d4e51d5..21473ea 100644
--- a/src/account/LMI_AccountManagementServiceProvider.c
+++ b/src/account/LMI_AccountManagementServiceProvider.c
@@ -38,6 +38,8 @@
 #include <unistd.h>
 #include <shadow.h>
 
+#include "lock.h"
+
 // Return values of functions
 // common
 #define RET_OK          0
@@ -54,6 +56,10 @@ static const CMPIBroker* _cb = NULL;
 static void LMI_AccountManagementServiceInitialize(const CMPIContext *ctx)
 {
     lmi_init(provider_name, _cb, ctx, provider_config_defaults);
+    if (init_lock_pools() == 0) {
+        error("Unable to initialize lock pool.");
+        exit (1);
+    }
 }
 
 static CMPIStatus LMI_AccountManagementServiceCleanup(
@@ -271,6 +277,12 @@ KUint32 LMI_AccountManagementService_CreateGroup(
         goto clean;
       }
 
+    char userlock[USERNAME_LEN_MAX] = {0};
+    /* -1 for NULL char */
+    strncpy(userlock, Name->chars, sizeof(userlock) - 1);
+    lmi_debug("Getting giant lock for user: %s", userlock);
+    get_giant_lock();
+
     pwdlockres = lckpwdf();
     if (pwdlockres != 0)
         warn("Cannot acquire passwd file lock\n");
@@ -337,10 +349,14 @@ KUint32 LMI_AccountManagementService_CreateGroup(
 
 clean:
 #undef FAIL
-    if (lue) lu_ent_free(lue);
-    if (luc) lu_end(luc);
     if (pwdlockres == 0)
         ulckpwdf();
+    lmi_debug("Releasing giant lock for user: %s", userlock);
+    release_giant_lock();
+    lmi_debug("Giant lock released for user %s", userlock);
+
+    if (lue) lu_ent_free(lue);
+    if (luc) lu_end(luc);
     return result;
 }
 
@@ -405,6 +421,12 @@ KUint32 LMI_AccountManagementService_CreateAccount(
         goto clean;
       }
 
+    char userlock[USERNAME_LEN_MAX] = {0};
+    /* -1 for NULL char */
+    strncpy(userlock, Name->chars, sizeof(userlock) - 1);
+    lmi_debug("Getting giant lock for user: %s", userlock);
+    get_giant_lock();
+
     pwdlockres = lckpwdf();
     if (pwdlockres != 0)
         warn("Cannot acquire passwd file lock\n");
@@ -586,13 +608,16 @@ output:
 
 clean:
 #undef FAIL
+    if (pwdlockres == 0)
+        ulckpwdf();
+    lmi_debug("Releasing giant lock for user: %s", userlock);
+    release_giant_lock();
+    lmi_debug("Giant lock released for user %s", userlock);
+
     free(group_name);
     if (lue) lu_ent_free(lue);
     if (lue_group) lu_ent_free(lue_group);
     if (luc) lu_end(luc);
-    if (pwdlockres == 0)
-        ulckpwdf();
-
     return result;
 }