Bug 13779 - Some of the samba code may start failing if the usnChanged value exceeds 32-bits
Summary: Some of the samba code may start failing if the usnChanged value exceeds 32-bits
Status: NEW
Alias: None
Product: Samba 4.1 and newer
Classification: Unclassified
Component: AD: LDB/DSDB/SAMDB (show other bugs)
Version: 4.9.0
Hardware: All All
: P5 normal (vote)
Target Milestone: ---
Assignee: Andrew Bartlett
QA Contact: Samba QA Contact
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-02-08 03:22 UTC by Tim Beale
Modified: 2019-02-08 03:22 UTC (History)
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Description Tim Beale 2019-02-08 03:22:40 UTC 
We were wondering whether usnChanged could feasibly be exhausted. Turns out it's 64-bit. However, it also turns out that some of the code treats it as a 32-bit value:

source3/libads/ldap.c:	if (!ads_pull_uint32(ads, res, "highestCommittedUSN", usn)) {
source3/libads/ldap_utils.c:					     uint32_t *first_usn,
source3/libads/ldap_utils.c:	uint32_t first_usn;
source3/libads/ldap_utils.c:				      uint32_t *first_usn,
source3/libads/ldap_utils.c:	uint32_t current_usn;
source3/libads/ldap_utils.c:		if (!ads_pull_uint32(ads, res, "usnChanged", first_usn)) {
source3/libads/ldap_utils.c:	if (!ads_pull_uint32(ads, res, "usnChanged", &current_usn)) {
source4/dsdb/kcc/kcc_drs_replica_info.c:				       uint32_t *attr_version, NTTIME *attr_change_time, uint32_t *attr_orig_usn)
source4/dsdb/kcc/kcc_drs_replica_info.c:	ntstatus = dsdb_get_extended_dn_uint32(attr_ext_dn, attr_version, "RMD_ORIGINATING_USN");
source4/dsdb/kcc/kcc_drs_replica_info.c:		uint32_t attr_originating_usn = 0;
source4/dsdb/samdb/ldb_modules/dirsync.c:				uint32_t tmp_usn = 0;
source4/dsdb/samdb/ldb_modules/dirsync.c:				uint32_t tmp_usn2 = 0;
source4/dsdb/samdb/ldb_modules/dirsync.c:				status = dsdb_get_extended_dn_uint32(dn->dn, &tmp_usn, "RMD_LOCAL_USN");
source4/dsdb/samdb/ldb_modules/dirsync.c:				status = dsdb_get_extended_dn_uint32(dn->dn, &tmp_usn2, "RMD_ORIGINATING_USN");

At some point we should probably look at this code more closely and fix it up. Otherwise parts of samba could start failing if the usnChanged exceeds 32-bits.