From c0bf5895173972a0b86633c7d61d0de46798bbe1 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Wed, 5 Apr 2023 12:16:24 -0400 Subject: export: Fix rootdir corner case in next_mnt() Currently the following setup causes failure: 1. /etc/exports: / *(rw,crossmnt,no_subtree_check,fsid=root) 2. /etc/nfs.conf: [exports] rootdir=/nfs_srv 3. Mounts: /root/fs1.ext4 on /nfs_srv type ext4 (rw,relatime) /root/fs2.ext4 on /nfs_srv/fs2 type ext4 (rw,relatime) 4. On the client: $ ls /nfs_client/fs2 ls: cannot open directory '/nfs_client/fs2': Stale file handle The problem is that next_mnt() misses the corner case that every mount is a sub-mount of "/". So it fails to see that /nfs_srv/fs2 is a mountpoint when the client asks for fs2 it and as consequence the crossmnt mechanism fails. Signed-off-by: Richard Weinberger Signed-off-by: Steve Dickson --- support/export/cache.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/support/export/cache.c b/support/export/cache.c index 2497d4f..1c52627 100644 --- a/support/export/cache.c +++ b/support/export/cache.c @@ -410,12 +410,16 @@ static char *next_mnt(void **v, char *p) *v = f; } else f = *v; - while ((me = getmntent(f)) != NULL && l > 1) { + while ((me = getmntent(f)) != NULL && l >= 1) { char *mnt_dir = nfsd_path_strip_root(me->mnt_dir); if (!mnt_dir) continue; + /* Everything below "/" is a proper sub-mount */ + if (strcmp(p, "/") == 0) + return mnt_dir; + if (strncmp(mnt_dir, p, l) == 0 && mnt_dir[l] == '/') return mnt_dir; } -- cgit v1.2.1