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From: Scott Mayhew <smayhew@redhat.com>
To: selinux@vger.kernel.org, linux-nfs@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH RFC v2 2/2] selinux: try to use preparsed sid before calling parse_sid()
Date: Thu, 20 Jan 2022 16:49:48 -0500	[thread overview]
Message-ID: <20220120214948.3637895-3-smayhew@redhat.com> (raw)
In-Reply-To: <20220120214948.3637895-1-smayhew@redhat.com>

Avoid unnecessary parsing of sids that have already been parsed via
selinux_sb_eat_lsm_opts().

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
 security/selinux/hooks.c | 85 ++++++++++++++++++++++++++++------------
 1 file changed, 61 insertions(+), 24 deletions(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index f27ca9e870c0..28ba5c8529fa 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -677,36 +677,52 @@ static int selinux_set_mnt_opts(struct super_block *sb,
 	 */
 	if (opts) {
 		if (opts->fscontext) {
-			rc = parse_sid(sb, opts->fscontext, &fscontext_sid);
-			if (rc)
-				goto out;
+			if (opts->preparsed & FSCONTEXT_MNT)
+				fscontext_sid = opts->fscontext_sid;
+			else {
+				rc = parse_sid(sb, opts->fscontext, &fscontext_sid);
+				if (rc)
+					goto out;
+			}
 			if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
 					fscontext_sid))
 				goto out_double_mount;
 			sbsec->flags |= FSCONTEXT_MNT;
 		}
 		if (opts->context) {
-			rc = parse_sid(sb, opts->context, &context_sid);
-			if (rc)
-				goto out;
+			if (opts->preparsed & CONTEXT_MNT)
+				context_sid = opts->context_sid;
+			else {
+				rc = parse_sid(sb, opts->context, &context_sid);
+				if (rc)
+					goto out;
+			}
 			if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
 					context_sid))
 				goto out_double_mount;
 			sbsec->flags |= CONTEXT_MNT;
 		}
 		if (opts->rootcontext) {
-			rc = parse_sid(sb, opts->rootcontext, &rootcontext_sid);
-			if (rc)
-				goto out;
+			if (opts->preparsed & ROOTCONTEXT_MNT)
+				rootcontext_sid = opts->rootcontext_sid;
+			else {
+				rc = parse_sid(sb, opts->rootcontext, &rootcontext_sid);
+				if (rc)
+					goto out;
+			}
 			if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
 					rootcontext_sid))
 				goto out_double_mount;
 			sbsec->flags |= ROOTCONTEXT_MNT;
 		}
 		if (opts->defcontext) {
-			rc = parse_sid(sb, opts->defcontext, &defcontext_sid);
-			if (rc)
-				goto out;
+			if (opts->preparsed & DEFCONTEXT_MNT)
+				defcontext_sid = opts->defcontext_sid;
+			else {
+				rc = parse_sid(sb, opts->defcontext, &defcontext_sid);
+				if (rc)
+					goto out;
+			}
 			if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
 					defcontext_sid))
 				goto out_double_mount;
@@ -2753,32 +2769,48 @@ static int selinux_sb_remount(struct super_block *sb, void *mnt_opts)
 		return 0;
 
 	if (opts->fscontext) {
-		rc = parse_sid(sb, opts->fscontext, &sid);
-		if (rc)
-			return rc;
+		if (opts->preparsed & FSCONTEXT_MNT)
+			sid = opts->fscontext_sid;
+		else {
+			rc = parse_sid(sb, opts->fscontext, &sid);
+			if (rc)
+				return rc;
+		}
 		if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
 			goto out_bad_option;
 	}
 	if (opts->context) {
-		rc = parse_sid(sb, opts->context, &sid);
-		if (rc)
-			return rc;
+		if (opts->preparsed & CONTEXT_MNT)
+			sid = opts->context_sid;
+		else {
+			rc = parse_sid(sb, opts->context, &sid);
+			if (rc)
+				return rc;
+		}
 		if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
 			goto out_bad_option;
 	}
 	if (opts->rootcontext) {
 		struct inode_security_struct *root_isec;
 		root_isec = backing_inode_security(sb->s_root);
-		rc = parse_sid(sb, opts->rootcontext, &sid);
-		if (rc)
-			return rc;
+		if (opts->preparsed & ROOTCONTEXT_MNT)
+			sid = opts->rootcontext_sid;
+		else {
+			rc = parse_sid(sb, opts->rootcontext, &sid);
+			if (rc)
+				return rc;
+		}
 		if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
 			goto out_bad_option;
 	}
 	if (opts->defcontext) {
-		rc = parse_sid(sb, opts->defcontext, &sid);
-		if (rc)
-			return rc;
+		if (opts->preparsed & DEFCONTEXT_MNT)
+			sid = opts->defcontext_sid;
+		else {
+			rc = parse_sid(sb, opts->defcontext, &sid);
+			if (rc)
+				return rc;
+		}
 		if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
 			goto out_bad_option;
 	}
@@ -2877,6 +2909,11 @@ static int selinux_fs_context_dup(struct fs_context *fc,
 		if (!opts->defcontext)
 			return -ENOMEM;
 	}
+	opts->fscontext_sid = src->fscontext_sid;
+	opts->context_sid = src->context_sid;
+	opts->rootcontext_sid = src->rootcontext_sid;
+	opts->defcontext_sid = src->defcontext_sid;
+	opts->preparsed = src->preparsed;
 	return 0;
 }
 
-- 
2.31.1


      parent reply	other threads:[~2022-01-20 21:50 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-20 21:49 [PATCH RFC v2 0/2] selinux: parse sids earlier to avoid doing memory allocations under spinlock Scott Mayhew
2022-01-20 21:49 ` [PATCH RFC v2 1/2] selinux: Fix selinux_sb_mnt_opts_compat() Scott Mayhew
2022-01-24 21:27   ` Paul Moore
2022-01-25 17:30     ` Scott Mayhew
2022-01-25 17:45       ` Paul Moore
2022-01-25 18:51         ` Scott Mayhew
2022-01-25 22:32           ` Paul Moore
2022-01-26 20:41             ` Scott Mayhew
2022-01-28  1:53               ` Paul Moore
2022-01-27  9:54   ` Ondrej Mosnacek
2022-01-28  2:25     ` Paul Moore
2022-01-31 12:46       ` Ondrej Mosnacek
2022-01-31 16:16         ` Paul Moore
2022-02-01 14:38           ` Ondrej Mosnacek
2022-02-01 16:19             ` Paul Moore
2022-01-20 21:49 ` Scott Mayhew [this message]

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