https://bugs.openldap.org/show_bug.cgi?id=10302

Issue ID: 10302 Summary: Double free of idcursor Product: OpenLDAP Version: 2.6.6 Hardware: x86_64 OS: Linux Status: UNCONFIRMED Keywords: needs_review Severity: normal Priority: --- Component: backends Assignee: bugs@openldap.org Reporter: simon.rupf@lzlabs.com Target Milestone: ---

Created attachment 1050 --> https://bugs.openldap.org/attachment.cgi?id=1050&action=edit proposed patch, which was created from current master, but also applies to 2.6.6

While switching from Oracle Linux (a RHEL clone) 8 to 9 one of our larger LDAP samples started causing a double free error at the end of the slapadd run. While I can't share the LDIF in question and it didn't consistently cause the issue, only every 5-6 times it ran, I could ran gdb and valgrind on it and suggest the attached patch that resolves that error to re-occur. I validated the patch still applies to the current master branch of openldap, as well as to 2.6.6 on EL9 where we encountered this.

The error originally observed was this (commands being run as ldap user):

[...] rm -r /var/lib/ldap mkdir /var/lib/ldap slapadd -l /tmp/lz_vault_convert_add.ldif -q -w -n 2 PROXIED attributeDescription "LZVAULTPROFILECOUNT" inserted. PROXIED attributeDescription "LZVAULTGLOBALPROFILECOUNT" inserted. -#################### 100.00% eta none elapsed 03s spd 4.2 M/s Closing DB...double free or corruption (!prev)

Under valgrind, the following trace could be observed:

valgrind --vgdb=full --leak-check=full --show-leak-kinds=all --track-origins=yes slapadd -l /tmp/lz_vault_convert_add.ldif -q -w -n 2 ==502== Memcheck, a memory error detector ==502== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al. ==502== Using Valgrind-3.23.0 and LibVEX; rerun with -h for copyright info ==502== Command: slapadd -l /tmp/lz_vault_convert_add.ldif -q -w -n 2 ==502== PROXIED attributeDescription "LZVAULTPROFILECOUNT" inserted. PROXIED attributeDescription "LZVAULTGLOBALPROFILECOUNT" inserted. ==502== Invalid read of size 8 ==502== at 0x1E65A9: mdb_cursor_close (mdb.c:7764) ==502== by 0x1F71B8: UnknownInlinedFun (tools.c:202) ==502== by 0x1F71B8: mdb_tool_entry_close (tools.c:152) ==502== by 0x1D8291: slapadd (slapadd.c:511) ==502== by 0x1348C6: main (main.c:540) ==502== Address 0x188c8af8 is 8 bytes inside a block of size 392 free'd ==502== at 0x4847B4C: free (vg_replace_malloc.c:989) ==502== by 0x22CEFE: mdb_cursors_close.isra.0 (mdb.c:2638) ==502== by 0x1EBAAE: mdb_txn_commit (mdb.c:3640) ==502== by 0x1F75E2: mdb_tool_entry_modify (tools.c:1066) ==502== by 0x1D9AF9: slap_tool_update_ctxcsn.part.0 (slapcommon.c:1069) ==502== by 0x1D8440: UnknownInlinedFun (slapcommon.c:962) ==502== by 0x1D8440: slapadd (slapadd.c:502) ==502== by 0x1348C6: main (main.c:540) ==502== Block was alloc'd at ==502== at 0x484482F: malloc (vg_replace_malloc.c:446) ==502== by 0x1E8699: mdb_cursor_open (mdb.c:7690) ==502== by 0x1F8C45: mdb_tool_entry_put (tools.c:707) ==502== by 0x1D8150: slapadd (slapadd.c:453) ==502== by 0x1348C6: main (main.c:540) [...]

Please advise if I can provide any further diagnostics, while I can still relatively easily reproduce the issue.