From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- drivers/md/dm-audit.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 drivers/md/dm-audit.c (limited to 'drivers/md/dm-audit.c') diff --git a/drivers/md/dm-audit.c b/drivers/md/dm-audit.c new file mode 100644 index 000000000..2e979eeb1 --- /dev/null +++ b/drivers/md/dm-audit.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Creating audit records for mapped devices. + * + * Copyright (C) 2021 Fraunhofer AISEC. All rights reserved. + * + * Authors: Michael Weiß + */ + +#include +#include +#include +#include +#include + +#include "dm-audit.h" +#include "dm-core.h" + +static struct audit_buffer *dm_audit_log_start(int audit_type, + const char *dm_msg_prefix, + const char *op) +{ + struct audit_buffer *ab; + + if (audit_enabled == AUDIT_OFF) + return NULL; + + ab = audit_log_start(audit_context(), GFP_KERNEL, audit_type); + if (unlikely(!ab)) + return NULL; + + audit_log_format(ab, "module=%s op=%s", dm_msg_prefix, op); + return ab; +} + +void dm_audit_log_ti(int audit_type, const char *dm_msg_prefix, const char *op, + struct dm_target *ti, int result) +{ + struct audit_buffer *ab = NULL; + struct mapped_device *md = dm_table_get_md(ti->table); + int dev_major = dm_disk(md)->major; + int dev_minor = dm_disk(md)->first_minor; + + switch (audit_type) { + case AUDIT_DM_CTRL: + ab = dm_audit_log_start(audit_type, dm_msg_prefix, op); + if (unlikely(!ab)) + return; + audit_log_task_info(ab); + audit_log_format(ab, " dev=%d:%d error_msg='%s'", dev_major, + dev_minor, !result ? ti->error : "success"); + break; + case AUDIT_DM_EVENT: + ab = dm_audit_log_start(audit_type, dm_msg_prefix, op); + if (unlikely(!ab)) + return; + audit_log_format(ab, " dev=%d:%d sector=?", dev_major, + dev_minor); + break; + default: /* unintended use */ + return; + } + + audit_log_format(ab, " res=%d", result); + audit_log_end(ab); +} +EXPORT_SYMBOL_GPL(dm_audit_log_ti); + +void dm_audit_log_bio(const char *dm_msg_prefix, const char *op, + struct bio *bio, sector_t sector, int result) +{ + struct audit_buffer *ab; + int dev_major = MAJOR(bio->bi_bdev->bd_dev); + int dev_minor = MINOR(bio->bi_bdev->bd_dev); + + ab = dm_audit_log_start(AUDIT_DM_EVENT, dm_msg_prefix, op); + if (unlikely(!ab)) + return; + + audit_log_format(ab, " dev=%d:%d sector=%llu res=%d", + dev_major, dev_minor, sector, result); + audit_log_end(ab); +} +EXPORT_SYMBOL_GPL(dm_audit_log_bio); -- cgit v1.3.1