diff options
| author | Fan Wu <wufan@kernel.org> | 2026-09-22 20:13:49 -0700 |
|---|---|---|
| committer | Fan Wu <wufan@kernel.org> | 2026-09-25 13:30:27 -0700 |
| commit | 2776e9c28513a1c855a94792b292cbcc533418c8 (patch) | |
| tree | 4e397474f21da51145f5e2cf2ce7d62366348fe2 | |
| parent | 9814077275eca36ebf8d510d2f076d235ff9f51a (diff) | |
| download | linux-2776e9c28513a1c855a94792b292cbcc533418c8.tar.gz linux-2776e9c28513a1c855a94792b292cbcc533418c8.zip | |
ipe: protect the dm-verity root hash with RCU
ipe_bdev_setintegrity() frees the old root hash when dm-verity publishes
a new one on ->preresume, while policy evaluation can still be
dereferencing it.
Protect the root hash with RCU. The evaluation path already runs under
rcu_read_lock().
Fixes: e155858dd995 ("ipe: add support for dm-verity as a trust provider")
Cc: stable@vger.kernel.org
Assisted-by: LLM
[FW: remove model name according to latest guideline]
Signed-off-by: Fan Wu <wufan@kernel.org>
| -rw-r--r-- | security/ipe/eval.c | 12 | ||||
| -rw-r--r-- | security/ipe/eval.h | 2 | ||||
| -rw-r--r-- | security/ipe/hooks.c | 22 |
3 files changed, 26 insertions, 10 deletions
diff --git a/security/ipe/eval.c b/security/ipe/eval.c index 21439c5be336..4a7be96c84f0 100644 --- a/security/ipe/eval.c +++ b/security/ipe/eval.c @@ -134,10 +134,14 @@ static bool evaluate_boot_verified(const struct ipe_eval_ctx *const ctx) static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx, struct ipe_prop *p) { - return !!ctx->ipe_bdev && - !!ctx->ipe_bdev->root_hash && - ipe_digest_eval(p->value, - ctx->ipe_bdev->root_hash); + const struct digest_info *root_hash; + + if (!ctx->ipe_bdev) + return false; + + root_hash = rcu_dereference(ctx->ipe_bdev->root_hash); + + return root_hash && ipe_digest_eval(p->value, root_hash); } #else static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx, diff --git a/security/ipe/eval.h b/security/ipe/eval.h index fef65a36468c..b26d1147d070 100644 --- a/security/ipe/eval.h +++ b/security/ipe/eval.h @@ -27,7 +27,7 @@ struct ipe_bdev { #ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE bool dm_verity_signed; #endif /* CONFIG_IPE_PROP_DM_VERITY_SIGNATURE */ - struct digest_info *root_hash; + struct digest_info __rcu *root_hash; }; #endif /* CONFIG_IPE_PROP_DM_VERITY */ diff --git a/security/ipe/hooks.c b/security/ipe/hooks.c index 0ae54a880405..d878b52ceec8 100644 --- a/security/ipe/hooks.c +++ b/security/ipe/hooks.c @@ -9,6 +9,7 @@ #include <linux/binfmts.h> #include <linux/mman.h> #include <linux/blk_types.h> +#include <linux/rcupdate.h> #include "ipe.h" #include "hooks.h" @@ -232,7 +233,20 @@ void ipe_bdev_free_security(struct block_device *bdev) { struct ipe_bdev *blob = ipe_bdev(bdev); - ipe_digest_free(blob->root_hash); + ipe_digest_free(rcu_access_pointer(blob->root_hash)); +} + +static void ipe_set_dmverity_roothash(struct ipe_bdev *blob, + struct digest_info *info) +{ + struct digest_info *old; + + /* Protected by device-mapper's md->suspend_lock */ + old = rcu_replace_pointer(blob->root_hash, info, true); + if (old) { + synchronize_rcu(); + ipe_digest_free(old); + } } #ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE @@ -280,8 +294,7 @@ int ipe_bdev_setintegrity(struct block_device *bdev, enum lsm_integrity_type typ return -EINVAL; if (!value) { - ipe_digest_free(blob->root_hash); - blob->root_hash = NULL; + ipe_set_dmverity_roothash(blob, NULL); return 0; } @@ -301,8 +314,7 @@ int ipe_bdev_setintegrity(struct block_device *bdev, enum lsm_integrity_type typ info->digest_len = digest->digest_len; - ipe_digest_free(blob->root_hash); - blob->root_hash = info; + ipe_set_dmverity_roothash(blob, info); return 0; err: |