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From:   Trond Myklebust <trondmy@gmail.com>
To:     Steve Dickson <SteveD@redhat.com>
Cc:     "J. Bruce Fields" <bfields@redhat.com>, linux-nfs@vger.kernel.org
Subject: [PATCH 3/3] mountd: Canonicalise the rootdir in exportent_mkrealpath()
Date:   Mon,  3 Jun 2019 13:12:27 -0400
Message-Id: <20190603171227.29148-4-trond.myklebust@hammerspace.com>
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 <20190603171227.29148-3-trond.myklebust@hammerspace.com>
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Ensure that we canonicalise the export path when generating the
real path.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 support/export/export.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/support/export/export.c b/support/export/export.c
index 82bbb54c5e9e..c753f68e4d63 100644
--- a/support/export/export.c
+++ b/support/export/export.c
@@ -14,6 +14,7 @@
 #include <sys/types.h>
 #include <sys/param.h>
 #include <netinet/in.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <dirent.h>
 #include <errno.h>
@@ -21,6 +22,7 @@
 #include "nfslib.h"
 #include "exportfs.h"
 #include "nfsd_path.h"
+#include "xlog.h"
 
 exp_hash_table exportlist[MCL_MAXTYPES] = {{NULL, {{NULL,NULL}, }}, }; 
 static int export_hash(char *);
@@ -38,8 +40,14 @@ exportent_mkrealpath(struct exportent *eep)
 	const char *chroot = nfsd_path_nfsd_rootdir();
 	char *ret = NULL;
 
-	if (chroot)
-		ret = nfsd_path_prepend_dir(chroot, eep->e_path);
+	if (chroot) {
+		char buffer[PATH_MAX];
+		if (realpath(chroot, buffer))
+			ret = nfsd_path_prepend_dir(buffer, eep->e_path);
+		else
+			xlog(D_GENERAL, "%s: failed to resolve path %s: %m",
+					__func__, chroot);
+	}
 	if (!ret)
 		ret = xstrdup(eep->e_path);
 	eep->e_realpath = ret;
-- 
2.21.0