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authorMichael Adam <obnox@samba.org>2008-08-05 22:38:44 +0200
committerMichael Adam <obnox@samba.org>2008-08-05 23:43:53 +0200
commitb59ed9c05f5d5831e6abf5db6f58a75ec98902f8 (patch)
tree3d1b2193b336c443072a87785b08317483ec3f84 /source3/lib
parent6e16022d625217bccc273f647c34f55030f78334 (diff)
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idmap_tdb2: fix a race condition in idmap_tdb2_allocate_id().
The race is a regression introduced by the change to dbwrap. It might have led to two concurrent processes returning the same id. This fix is achieved by changing dbwrap_change_uint32_atomic() to match the original behaviour of tdb_change_uint32_atomic(), which is the following: *oldval is used as initial value when the value does not yet exist and that the old value should be returned in *oldval. dbwrap_change_uint32_atomic() is used (only) in idmap_tdb2.c, to get new ids. Michael (This used to be commit 72bd83fea7572a6202027b200d192c05023aa633)
Diffstat (limited to 'source3/lib')
-rw-r--r--source3/lib/dbwrap_util.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/source3/lib/dbwrap_util.c b/source3/lib/dbwrap_util.c
index 07e50827d4..14baec11a3 100644
--- a/source3/lib/dbwrap_util.c
+++ b/source3/lib/dbwrap_util.c
@@ -110,9 +110,13 @@ uint32_t dbwrap_change_uint32_atomic(struct db_context *db, const char *keystr,
return -1;
}
- if ((rec->value.dptr != NULL)
- && (rec->value.dsize == sizeof(val))) {
+ if (rec->value.dptr == NULL) {
+ val = *oldval;
+ } else if (rec->value.dsize == sizeof(val)) {
val = IVAL(rec->value.dptr, 0);
+ *oldval = val;
+ } else {
+ return -1;
}
val += change_val;