From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 451773B0AF0; Tue, 19 May 2026 20:09:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779221380; cv=none; b=Vx5v5nS23AZJFRuXRmqTa2LbcsCBzc85Xj+7TOFFtrQChAKin9GPbE9o5gkOdQgxBii1++50FHg8Lt3rWCiGiiClWiHeosYwuqOUnQOfw00L7kllw8kcs0b3igk8UTiIRhbBewxy67GIu5YXJaQK6J4fba7nrzBhmlUM3X0cHvQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779221380; c=relaxed/simple; bh=DK/2lsORPLzwBN2/kK76cxy++/gAwmQ/2uidG2vMd9g=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Y1B6ftQCum7GkQ7ls8rWnT73vd8zv30C1KTBfB2BwsgnD4LB3FNSIT4j3oPveSBJZayDOXGPZiVo0THh6XZmdveC/8Tr5yFc500IK4ei8bFT492Jj0NRiW95fCZiiMdW3ihpVTilayuvxdfe8LwCS+a1soY4QRJsXNtBwhdORn8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mMTJbi4n; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mMTJbi4n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B05541F000E9; Tue, 19 May 2026 20:09:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779221378; bh=YI2mdONzYKZOxRqC1fr+F+7SB5OH+cuh+BqlVGdL64g=; h=From:To:Cc:Subject:Date; b=mMTJbi4n/BAH0ZWUWnrjfE3VmcZTHIwyGPdXhKytYwsRit0/Q0DyRvFebd9INLyvk 6341xscp2jLbx2UxUDPU8Z78DMES+cCTDM5U1raITzq6qED4NXKIuxzwIwHE+DFzmg 3X1lqLq6aRv2twu/bF7FskElQUCbuUCkjfMj9leQsow8jPLHIcEHXxa9k4Z8MbfXRj HSn5p+bX5xdn7p6zRaRbcicyxCTPOPcKTTFxKsj5JlHacmcZ7zaa1qqeHuAwT4O79f FIgJiyqvzmCCESB7jUQaHIIenFXOvY6W9uM9Hvev4LV87LG5J9AGsPY8acK50khtzl uq+VKFOKojwHQ== From: KP Singh To: bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, Xianrui Dong , KP Singh Subject: [PATCH] bpf: reject NULL data/sig in bpf_verify_pkcs7_signature Date: Tue, 19 May 2026 22:09:33 +0200 Message-ID: <20260519200933.30752-1-kpsingh@kernel.org> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit __bpf_dynptr_data() can return NULL (FILE dynptrs, any non-contiguous backing). bpf_verify_pkcs7_signature() forwards the pointer to verify_pkcs7_signature() unchecked, causing a NULL deref in asn1_ber_decoder() reachable from a sleepable BPF LSM at lsm.s/bpf. NULL-check both pointers and reject with -EINVAL. Mirrors the guards already in kernel/bpf/crypto.c. Fixes: 865b0566d8f1 ("bpf: Add bpf_verify_pkcs7_signature() kfunc") Reported-by: Xianrui Dong Signed-off-by: KP Singh --- kernel/bpf/helpers.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 2bb60200c266..b5314c9fed3c 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -4241,8 +4241,13 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_p, data_len = __bpf_dynptr_size(data_ptr); data = __bpf_dynptr_data(data_ptr, data_len); + if (!data) + return -EINVAL; + sig_len = __bpf_dynptr_size(sig_ptr); sig = __bpf_dynptr_data(sig_ptr, sig_len); + if (!sig) + return -EINVAL; return verify_pkcs7_signature(data, data_len, sig, sig_len, trusted_keyring->key, -- 2.53.0