From nobody Tue Dec 16 20:29:05 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C3961327201; Wed, 10 Dec 2025 17:21:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765387279; cv=none; b=Yq8i5ou7K2zfVOp/iKMBYjscBW8JhrekyuH9o4JhaxqS6J14ZasK+tjzYPErJfwzU0hl41SW3IX6QiDK3poqx3MMMvybo0nkUdGFSV/HMEZbG52wc3FxqevQTHqGnsKdvBJodPIwj+Xng4QSzg5zwDB3CeBcM/IxNVR3JXaGE7Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765387279; c=relaxed/simple; bh=ose2oB/fvx8BkW6CVHK5os3jHRlOiK5rAT97U08pq4o=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=fj+5weI7sGHEW3bIlXIV0w0sn/ML5dLPNj8foCWDat+S+yeckr9Ef+isCR2UDgnBLthz3Bz7EpgypwuaWHOsmmG6ZfX0IHCyLQjewp0XRYF5YRa+DFfj7FC6n+fwbyWroiiCZfQmRtKBOKgzX+QAXo3/AoKv6kytkEEj6c2uu88= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tpUfYW3C; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tpUfYW3C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C57BDC4CEF1; Wed, 10 Dec 2025 17:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765387279; bh=ose2oB/fvx8BkW6CVHK5os3jHRlOiK5rAT97U08pq4o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tpUfYW3CJAtqL5S3ySrAUNOfthY6VO45ff4gk18o0lkNLxPBfZmHFQMcPnae6EsLL JaTKlcPK1E+ttAmn4x0imK4gFb/wBqcz6ihhrIC37FPEu9Z/pJfuoTkl62ks28vBbg 9cWgHDAs1eTvwlqRC2he4zo0jyXPpU2Vkmaz+woclH44juIxRgd3splrFbuCgYyp1n p7h+gzDJ9S/R0ZmAznq5qfClV2Npl5VlTo/pttVuOoKrcB9DRaoYhziTZGRh8fD47P uX01UBvOrQm2If1hoRROCEmuqx+XfCDrKaT3xJqFQ4xdHNtM97jxmhUErCmH7hIMef DRx+FpaeEW6dQ== From: Jarkko Sakkinen To: linux-integrity@vger.kernel.org Cc: Jarkko Sakkinen , Peter Huewe , Jason Gunthorpe , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , linux-kernel@vger.kernel.org (open list), keyrings@vger.kernel.org (open list:KEYS/KEYRINGS), linux-security-module@vger.kernel.org (open list:SECURITY SUBSYSTEM) Subject: [PATCH v4 8/8] tpm: In tpm_get_random() replace 'retries' with a zero check Date: Wed, 10 Dec 2025 19:20:26 +0200 Message-Id: <20251210172027.109938-9-jarkko@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20251210172027.109938-1-jarkko@kernel.org> References: <20251210172027.109938-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Check for zero byte read instead of having retries counter in order to make wait flag properly enforcing. Progress is still guaranteed given the zero check and iterations are capped up to TPM_MAX_RNG_DATA iterations at most (as per theoretical limit). Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm-interface.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interf= ace.c index 5cc2bbabd57a..594ad095a90b 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -620,7 +620,6 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size= _t max, bool wait) { u32 num_bytes =3D max; u8 *out_ptr =3D out; - int retries =3D 5; int total =3D 0; int rc; =20 @@ -646,8 +645,12 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, siz= e_t max, bool wait) else rc =3D tpm1_get_random(chip, out_ptr, num_bytes); =20 - if (rc < 0) + if (rc <=3D 0) { + if (!rc) + rc =3D -EIO; + goto err; + } =20 if (!wait) { total =3D rc; @@ -657,7 +660,7 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size= _t max, bool wait) out_ptr +=3D rc; total +=3D rc; num_bytes -=3D rc; - } while (retries-- && total < max); + } while (total < max); =20 tpm_put_ops(chip); return total ? total : -EIO; --=20 2.39.5