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| author | Michael Adam <obnox@samba.org> | 2008-08-05 22:38:44 +0200 |
|---|---|---|
| committer | Michael Adam <obnox@samba.org> | 2008-08-05 23:43:53 +0200 |
| commit | b59ed9c05f5d5831e6abf5db6f58a75ec98902f8 (patch) | |
| tree | 3d1b2193b336c443072a87785b08317483ec3f84 | |
| parent | 6e16022d625217bccc273f647c34f55030f78334 (diff) | |
| download | samba-b59ed9c05f5d5831e6abf5db6f58a75ec98902f8.tar.gz samba-b59ed9c05f5d5831e6abf5db6f58a75ec98902f8.tar.bz2 samba-b59ed9c05f5d5831e6abf5db6f58a75ec98902f8.zip | |
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)
| -rw-r--r-- | source3/lib/dbwrap_util.c | 8 |
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; |