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Thu, 01 Oct 2026 14:39:28 -0700 (PDT) Received: from adriano.lan ([2803:9810:3d22:1608:1620:60f3:83ff:8ca9]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-34f14f660f1sm951950eec.13.2026.10.01.14.39.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Oct 2026 14:39:27 -0700 (PDT) From: Adriano Cordova To: Tyler Hicks Cc: ecryptfs@vger.kernel.org, linux-kernel@vger.kernel.org, Adriano Cordova , stable@vger.kernel.org, syzbot+03c68e42ce4b33f7ce9b@syzkaller.appspotmail.com Subject: [PATCH] ecryptfs: validate auth tok payload size Date: Thu, 1 Oct 2026 18:39:15 -0300 Message-ID: <20261001213915.1326602-1-adrianox@gmail.com> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Validate that a key payload is large enough to hold a struct ecryptfs_auth_tok, and that the password token's session_key_encryption_key_bytes fits within session_key_encryption_key[], before the payload is dereferenced. Cc: Reported-by: syzbot+03c68e42ce4b33f7ce9b@syzkaller.appspotmail.com Tested-by: syzbot+03c68e42ce4b33f7ce9b@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=03c68e42ce4b33f7ce9b Signed-off-by: Adriano Cordova --- fs/ecryptfs/ecryptfs_kernel.h | 6 ++++++ fs/ecryptfs/keystore.c | 7 +++++++ 2 files changed, 13 insertions(+) diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index 58165928ed1e..4315c18ba1cd 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -88,6 +88,9 @@ ecryptfs_get_encrypted_key_payload_data(struct key *key) if (!payload) return ERR_PTR(-EKEYREVOKED); + if (payload->payload_datalen < sizeof(struct ecryptfs_auth_tok)) + return ERR_PTR(-EINVAL); + return (struct ecryptfs_auth_tok *)payload->payload_data; } @@ -124,6 +127,9 @@ ecryptfs_get_key_payload_data(struct key *key) if (!ukp) return ERR_PTR(-EKEYREVOKED); + if (ukp->datalen < sizeof(struct ecryptfs_auth_tok)) + return ERR_PTR(-EINVAL); + return (struct ecryptfs_auth_tok *)ukp->data; } diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c index 51651314b7a6..7f2dbc81fcbc 100644 --- a/fs/ecryptfs/keystore.c +++ b/fs/ecryptfs/keystore.c @@ -477,6 +477,13 @@ ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, rc = -EINVAL; goto out; } + if ((*auth_tok)->token_type == ECRYPTFS_PASSWORD + && (*auth_tok)->token.password.session_key_encryption_key_bytes + > ECRYPTFS_MAX_KEY_BYTES) { + printk(KERN_ERR "Invalid password auth_tok sKEK size\n"); + rc = -EINVAL; + goto out; + } out: return rc; } -- 2.51.0