Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1740177

[PATCH v2 4/6] KEYS: load key flags and expiry time atomically in keyring_search_iterator()

Show all headers | View raw

From: Eric Biggers <ebiggers@google.com>

Similar to the case for key_validate(), we should load the key ->flags
and ->expiry once atomically in keyring_search_iterator(), since they
can be changed concurrently whenever the key semaphore isn't held.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 security/keys/keyring.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 7fc661f492d3..1dfff0eac474 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -553,7 +553,7 @@ static int keyring_search_iterator(const void *object, void *iterator_data)
 {
 	struct keyring_search_context *ctx = iterator_data;
 	const struct key *key = keyring_ptr_to_key(object);
-	unsigned long kflags = key->flags;
+	unsigned long kflags = READ_ONCE(key->flags);
 
 	kenter("{%d}", key->serial);
 
@@ -565,6 +565,8 @@ static int keyring_search_iterator(const void *object, void *iterator_data)
 
 	/* skip invalidated, revoked and expired keys */
 	if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
+		time_t expiry = READ_ONCE(key->expiry);
+
 		if (kflags & ((1 << KEY_FLAG_INVALIDATED) |
 			      (1 << KEY_FLAG_REVOKED))) {
 			ctx->result = ERR_PTR(-EKEYREVOKED);
@@ -572,7 +574,7 @@ static int keyring_search_iterator(const void *object, void *iterator_data)
 			goto skipped;
 		}
 
-		if (key->expiry && ctx->now.tv_sec >= key->expiry) {
+		if (expiry && ctx->now.tv_sec >= expiry) {
 			if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED))
 				ctx->result = ERR_PTR(-EKEYEXPIRED);
 			kleave(" = %d [expire]", ctx->skipped_ret);
-- 
2.14.1.992.g2c7b836f3a-goog

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

[PATCH v2 4/6] KEYS: load key flags and expiry time atomically in keyring_search_iterator() Eric Biggers <ebiggers3@gmail.com> - 2017-09-26 22:20 +0200

csiph-web