From mboxrd@z Thu Jan 1 00:00:00 1970 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 4724C32E747; Wed, 17 Sep 2025 12:54:49 +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=1758113689; cv=none; b=RY6MRSsd0KF3MgZQQ1q15wE/sLgCQSF63tIWsUoEGEhNccj+nY2xql+DX27qbYEtF7bUyOUsrEbbIPEzxlCG5lKZjW8lyN3yLGazWUoieis1bJUwMXaG8pbLaOYN4R7BCBK7UsoHFwjVURftG3LLInoacVzho84ZZAZwwjyhikk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758113689; c=relaxed/simple; bh=8j6OeRO5DJrAT42+X34Ma1EhdZBAb8KkPc00lROBXbo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=U8fy+Oeu0liX1lDq3eiaWlgblAlzMAlYLWM36YIg5T6x7o3nGO+MTBRc7cQKLIQLD+pslpK9zN5324X8RX6cOnACOf/T14cyNYjBF+LOpsDhctfSqTk5clK6qCneEZcSbTkDipfWOyCXGa7k8IwUX8U9XzptXXR/HzH1ZMA4XM4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IAgU80jB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="IAgU80jB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEC67C4CEF5; Wed, 17 Sep 2025 12:54:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1758113689; bh=8j6OeRO5DJrAT42+X34Ma1EhdZBAb8KkPc00lROBXbo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IAgU80jBT8zTJqelkf+sW9H0ketRchuRFO2UsAAHA7ScXnlY1uQcIwxtL5S6/4iyv xzi+Ro24z6HPYwYNyk7WHoRcQSADejYZsn8X4GSmwcKZ7APFoSkiuhybIDLk1OW9nT 6oxuUzwvccIJbrX/xncl+l55wcXzWiHF8MW5uWbw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Stefan Berger , Petr Vorel , Roberto Sassu , Mimi Zohar , Sasha Levin Subject: [PATCH 6.6 008/101] ima: limit the number of ToMToU integrity violations Date: Wed, 17 Sep 2025 14:33:51 +0200 Message-ID: <20250917123337.070995002@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250917123336.863698492@linuxfoundation.org> References: <20250917123336.863698492@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mimi Zohar [ Upstream commit a414016218ca97140171aa3bb926b02e1f68c2cc ] Each time a file in policy, that is already opened for read, is opened for write, a Time-of-Measure-Time-of-Use (ToMToU) integrity violation audit message is emitted and a violation record is added to the IMA measurement list. This occurs even if a ToMToU violation has already been recorded. Limit the number of ToMToU integrity violations per file open for read. Note: The IMA_MAY_EMIT_TOMTOU atomic flag must be set from the reader side based on policy. This may result in a per file open for read ToMToU violation. Since IMA_MUST_MEASURE is only used for violations, rename the atomic IMA_MUST_MEASURE flag to IMA_MAY_EMIT_TOMTOU. Cc: stable@vger.kernel.org # applies cleanly up to linux-6.6 Tested-by: Stefan Berger Reviewed-by: Petr Vorel Tested-by: Petr Vorel Reviewed-by: Roberto Sassu Signed-off-by: Mimi Zohar [ adapted IMA flag definitions location from ima.h to integrity.h ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- security/integrity/ima/ima_main.c | 16 +++++++++++----- security/integrity/integrity.h | 3 ++- 2 files changed, 13 insertions(+), 6 deletions(-) --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -128,16 +128,22 @@ static void ima_rdwr_violation_check(str if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) { if (!iint) iint = integrity_iint_find(inode); + /* IMA_MEASURE is set from reader side */ - if (iint && test_bit(IMA_MUST_MEASURE, - &iint->atomic_flags)) + if (iint && test_and_clear_bit(IMA_MAY_EMIT_TOMTOU, + &iint->atomic_flags)) send_tomtou = true; } } else { if (must_measure) - set_bit(IMA_MUST_MEASURE, &iint->atomic_flags); - if (inode_is_open_for_write(inode) && must_measure) - send_writers = true; + set_bit(IMA_MAY_EMIT_TOMTOU, &iint->atomic_flags); + + /* Limit number of open_writers violations */ + if (inode_is_open_for_write(inode) && must_measure) { + if (!test_and_set_bit(IMA_EMITTED_OPENWRITERS, + &iint->atomic_flags)) + send_writers = true; + } } if (!send_tomtou && !send_writers) --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -74,7 +74,8 @@ #define IMA_UPDATE_XATTR 1 #define IMA_CHANGE_ATTR 2 #define IMA_DIGSIG 3 -#define IMA_MUST_MEASURE 4 +#define IMA_MAY_EMIT_TOMTOU 4 +#define IMA_EMITTED_OPENWRITERS 5 enum evm_ima_xattr_type { IMA_XATTR_DIGEST = 0x01,