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| author | Rusty Russell <rusty@rustcorp.com.au> | 2010-02-04 23:59:54 +1030 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2010-02-10 16:56:14 +1030 |
| commit | b37b452cb8c1f56b37b04abe7bffdede371ca361 (patch) | |
| tree | 337e63a2be310ca1107aa37ec5bd18b5aa705fd8 /lib/tdb | |
| parent | 6269cdcd1538e2e3cead9e0f3c156b0363d607a0 (diff) | |
| download | samba-b37b452cb8c1f56b37b04abe7bffdede371ca361.tar.gz samba-b37b452cb8c1f56b37b04abe7bffdede371ca361.tar.bz2 samba-b37b452cb8c1f56b37b04abe7bffdede371ca361.zip | |
tdb: fix recovery reuse after crash
If a process (or the machine) dies after just after writing the
recovery head (pointing at the end of file), the recovery record will filled
with 0x42. This will not invoke a recovery on open, since rec.magic
!= TDB_RECOVERY_MAGIC.
Unfortunately, the first transaction commit will happily reuse that
area: tdb_recovery_allocate() doesn't check the magic. The recovery
record has length 0x42424242, and it writes that back into the
now-valid-looking transaction header) for the next comer (which
happens to be tdb_wipe_all in my tests).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'lib/tdb')
| -rw-r--r-- | lib/tdb/common/transaction.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/lib/tdb/common/transaction.c b/lib/tdb/common/transaction.c index ed7e298a6e..67104eff7f 100644 --- a/lib/tdb/common/transaction.c +++ b/lib/tdb/common/transaction.c @@ -695,10 +695,16 @@ static int tdb_recovery_allocate(struct tdb_context *tdb, rec.rec_len = 0; - if (recovery_head != 0 && - methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) { - TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery record\n")); - return -1; + if (recovery_head != 0) { + if (methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_recovery_allocate: failed to read recovery record\n")); + return -1; + } + /* ignore invalid recovery regions: can happen in crash */ + if (rec.magic != TDB_RECOVERY_MAGIC && + rec.magic != TDB_RECOVERY_INVALID_MAGIC) { + recovery_head = 0; + } } *recovery_size = tdb_recovery_size(tdb); |