Re: [PATCH] dm-verity: clear LSM integrity state on suspend
flat view
From: sashiko-bot@kernel.org
Date: 2026-09-21 22:16:27
Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider: - [High] dm-verity: clearing LSM state on suspend breaks IPE for cached files - [High] ipe: Use-After-Free in evaluate_dmv_roothash() due to missing RCU -- commit 0a1a0f42158da1707e32f8b9739a8420e73985d1 Author: Fan Wu [off-list ref] dm-verity: clear LSM integrity state on suspend This commit updates dm-verity to clear the published root hash and signature state from the LSM security blob during verity_postsuspend(). This prevents the block device from retaining stale attributes if the verity target is replaced with a different target type.
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diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c index cb105ccc47ecb..6d589867623c0 100644 --- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c
[ ... ]
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@@ -1779,8 +1781,31 @@ static int verity_preresume(struct dm_target *ti) return r; } +static void verity_security_clear_integrity(struct dm_target *ti) +{ + struct block_device *bdev = dm_disk(dm_table_get_md(ti->table))->part0; + + security_bdev_setintegrity(bdev, LSM_INT_DMVERITY_ROOTHASH, NULL, 0);
[Severity: High]
Does passing NULL to security_bdev_setintegrity() trigger a use-after-free
in IPE?
When this is called, ipe_bdev_setintegrity() appears to free the root hash
without RCU synchronization:
security/ipe/hooks.c:ipe_bdev_setintegrity() {
if (!value) {
ipe_digest_free(blob->root_hash);
blob->root_hash = NULL;
...
If a concurrent thread is evaluating an mprotect or execve call, could it
dereference this freed memory in evaluate_dmv_roothash()?
security/ipe/eval.c:evaluate_dmv_roothash() {
...
ipe_digest_eval(p->value, ctx->ipe_bdev->root_hash);
...
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+ verity_security_clear_signature(bdev); +} + +#else + +static inline void verity_security_clear_integrity(struct dm_target *ti) +{ +} + #endif /* CONFIG_SECURITY */ +static void verity_postsuspend(struct dm_target *ti) +{ + struct dm_verity *v = ti->private; + + flush_workqueue(v->verify_wq); + dm_bufio_client_reset(v->bufio); + verity_security_clear_integrity(ti);
[Severity: High] Does unconditionally clearing the integrity state on every table suspend break IPE evaluation for already cached files? During a temporary freeze or table reload, clearing the LSM integrity state will cause concurrent VFS operations on already-cached files to see a cleared state. Will this result in spurious -EACCES failures since IPE will deny access despite the files being valid?
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+} + static struct target_type verity_target = { .name = "verity", /* Note: the LSMs depend on the singleton and immutable features */
-- Sashiko AI review · https://sashiko.dev/#/patchset/20260921220516.121589-1-wufan@kernel.org?part=1