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From:   bfields@fieldses.org
To:     Steve Dickson <steved@redhat.com>
Cc:     linux-nfs@vger.kernel.org,
        Trond Myklebust <trondmy@hammerspace.com>,
        "J. Bruce Fields" <bfields@redhat.com>
Subject: [PATCH 1/2] mountd: allow high ports on all pseudofs exports
Date:   Wed,  2 Dec 2020 20:14:56 -0500
Message-Id: <1606958097-9041-1-git-send-email-bfields@fieldses.org>
In-Reply-To: <20201203010546.GB348347@pick.fieldses.org>
References: <20201203010546.GB348347@pick.fieldses.org>
Precedence: bulk

From: "J. Bruce Fields" <bfields@redhat.com>

We originally tried to grant permissions on the v4 pseudoroot filesystem
that were the absolute minimum required for a client to reach a given
export.  This turns out to be complicated, and we've never gotten it
quite right.  Also, the tradition from the MNT protocol was to allow
anyone to browse the list of exports.

So, do as we already did with security flavors and just allow clients
from high ports to access the whole pseudofilesystem.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
 utils/mountd/v4root.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/utils/mountd/v4root.c b/utils/mountd/v4root.c
index a9ea167a07e0..39dd87a94e59 100644
--- a/utils/mountd/v4root.c
+++ b/utils/mountd/v4root.c
@@ -36,7 +36,7 @@ static nfs_export pseudo_root = {
 		.e_path = "/",
 		.e_flags = NFSEXP_READONLY | NFSEXP_ROOTSQUASH
 				| NFSEXP_NOSUBTREECHECK | NFSEXP_FSID
-				| NFSEXP_V4ROOT,
+				| NFSEXP_V4ROOT | NFSEXP_INSECURE_PORT,
 		.e_anonuid = 65534,
 		.e_anongid = 65534,
 		.e_squids = NULL,
@@ -55,13 +55,11 @@ static nfs_export pseudo_root = {
 };
 
 static void
-set_pseudofs_security(struct exportent *pseudo, int flags)
+set_pseudofs_security(struct exportent *pseudo)
 {
 	struct flav_info *flav;
 	int i;
 
-	if (flags & NFSEXP_INSECURE_PORT)
-		pseudo->e_flags |= NFSEXP_INSECURE_PORT;
 	if ((flags & NFSEXP_ROOTSQUASH) == 0)
 		pseudo->e_flags &= ~NFSEXP_ROOTSQUASH;
 	for (flav = flav_map; flav < flav_map + flav_map_size; flav++) {
@@ -70,8 +68,7 @@ set_pseudofs_security(struct exportent *pseudo, int flags)
 		i = secinfo_addflavor(flav, pseudo);
 		new = &pseudo->e_secinfo[i];
 
-		if (flags & NFSEXP_INSECURE_PORT)
-			new->flags |= NFSEXP_INSECURE_PORT;
+		new->flags |= NFSEXP_INSECURE_PORT;
 	}
 }
 
@@ -90,7 +87,7 @@ v4root_create(char *path, nfs_export *export)
 	strncpy(eep.e_path, path, sizeof(eep.e_path)-1);
 	if (strcmp(path, "/") != 0)
 		eep.e_flags &= ~NFSEXP_FSID;
-	set_pseudofs_security(&eep, curexp->e_flags);
+	set_pseudofs_security(&eep);
 	exp = export_create(&eep, 0);
 	if (exp == NULL)
 		return NULL;
@@ -138,7 +135,7 @@ pseudofs_update(char *hostname, char *path, nfs_export *source)
 		return 0;
 	}
 	/* Update an existing V4ROOT export: */
-	set_pseudofs_security(&exp->m_export, source->m_export.e_flags);
+	set_pseudofs_security(&exp->m_export);
 	return 0;
 }
 
-- 
2.28.0