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 CF3B034189; Fri, 24 Nov 2023 19:07:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="nKc6ByBW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D91BC433C8; Fri, 24 Nov 2023 19:07:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700852844; bh=tNtjrNknEjLjBwuKi/DuSUy5xckuovAZQSa1WZDw/YI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nKc6ByBWEKl6I30eiSL8RCdLCqhdXtJZTotTvFwGNn8uA+94n0MVUwUXcJIacbB7p g4CjzbfBkyNU3VYOTlcPabeh+DabVaP4ANEgV1g6AcHhlszrVS74zA2l5DYRaPc4Kb 8Ph4epbLKgoxamo//eMpENIafzQ9g8WtQlRC6NGM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Amir Goldstein , Eric Snowberg , Raul E Rangel , Mimi Zohar Subject: [PATCH 5.10 121/193] ima: detect changes to the backing overlay file Date: Fri, 24 Nov 2023 17:54:08 +0000 Message-ID: <20231124171952.068626895@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231124171947.127438872@linuxfoundation.org> References: <20231124171947.127438872@linuxfoundation.org> User-Agent: quilt/0.67 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 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mimi Zohar commit b836c4d29f2744200b2af41e14bf50758dddc818 upstream. Commit 18b44bc5a672 ("ovl: Always reevaluate the file signature for IMA") forced signature re-evaulation on every file access. Instead of always re-evaluating the file's integrity, detect a change to the backing file, by comparing the cached file metadata with the backing file's metadata. Verifying just the i_version has not changed is insufficient. In addition save and compare the i_ino and s_dev as well. Reviewed-by: Amir Goldstein Tested-by: Eric Snowberg Tested-by: Raul E Rangel Cc: stable@vger.kernel.org Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/super.c | 2 +- security/integrity/ima/ima_api.c | 5 +++++ security/integrity/ima/ima_main.c | 16 +++++++++++++++- security/integrity/integrity.h | 2 ++ 4 files changed, 23 insertions(+), 2 deletions(-) --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -2028,7 +2028,7 @@ static int ovl_fill_super(struct super_b sb->s_xattr = ovl_xattr_handlers; sb->s_fs_info = ofs; sb->s_flags |= SB_POSIXACL; - sb->s_iflags |= SB_I_SKIP_SYNC | SB_I_IMA_UNVERIFIABLE_SIGNATURE; + sb->s_iflags |= SB_I_SKIP_SYNC; err = -ENOMEM; root_dentry = ovl_get_root(sb, upperpath.dentry, oe); --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -212,6 +212,7 @@ int ima_collect_measurement(struct integ { const char *audit_cause = "failed"; struct inode *inode = file_inode(file); + struct inode *real_inode = d_real_inode(file_dentry(file)); const char *filename = file->f_path.dentry->d_name.name; int result = 0; int length; @@ -262,6 +263,10 @@ int ima_collect_measurement(struct integ iint->ima_hash = tmpbuf; memcpy(iint->ima_hash, &hash, length); iint->version = i_version; + if (real_inode != inode) { + iint->real_ino = real_inode->i_ino; + iint->real_dev = real_inode->i_sb->s_dev; + } /* Possibly temporary failure due to type of read (eg. O_DIRECT) */ if (!result) --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -26,6 +26,7 @@ #include #include #include +#include #include "ima.h" @@ -197,7 +198,7 @@ static int process_measurement(struct fi u32 secid, char *buf, loff_t size, int mask, enum ima_hooks func) { - struct inode *inode = file_inode(file); + struct inode *backing_inode, *inode = file_inode(file); struct integrity_iint_cache *iint = NULL; struct ima_template_desc *template_desc = NULL; char *pathbuf = NULL; @@ -271,6 +272,19 @@ static int process_measurement(struct fi iint->measured_pcrs = 0; } + /* Detect and re-evaluate changes made to the backing file. */ + backing_inode = d_real_inode(file_dentry(file)); + if (backing_inode != inode && + (action & IMA_DO_MASK) && (iint->flags & IMA_DONE_MASK)) { + if (!IS_I_VERSION(backing_inode) || + backing_inode->i_sb->s_dev != iint->real_dev || + backing_inode->i_ino != iint->real_ino || + !inode_eq_iversion(backing_inode, iint->version)) { + iint->flags &= ~IMA_DONE_MASK; + iint->measured_pcrs = 0; + } + } + /* Determine if already appraised/measured based on bitmask * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED, * IMA_AUDIT, IMA_AUDITED) --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -131,6 +131,8 @@ struct integrity_iint_cache { unsigned long flags; unsigned long measured_pcrs; unsigned long atomic_flags; + unsigned long real_ino; + dev_t real_dev; enum integrity_status ima_file_status:4; enum integrity_status ima_mmap_status:4; enum integrity_status ima_bprm_status:4;