git: b525eaaa4aaf - stable/13 - ufs: Update *eofflag upon a read of an unlinked directory

[Mark Johnston]

The branch stable/13 has been updated by markj:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=b525eaaa4aafeee857d1abef27d7ddf1af76846f

commit b525eaaa4aafeee857d1abef27d7ddf1af76846f
Author:     Mark Johnston <ma...@freebsd.org>
AuthorDate: 2023-12-21 18:26:13 +0000
Commit:     Mark Johnston <ma...@freebsd.org>
CommitDate: 2023-12-28 03:04:22 +0000

    ufs: Update *eofflag upon a read of an unlinked directory
    
    If the directory is unlinked, no further entries will be returned, but
    we return no error.  At least one caller (vn_dir_next_dirent()) asserts
    that a VOP_READDIR call which returns no error and no entries will set
    *eofflag != 0, so the current behaviour of UFS can trigger an assertion
    failure.
    
    Simply set *eofflag in this scenario.
    
    Reviewed by:    olce, kib
    Reported by:    syzkaller
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D43089
    
    (cherry picked from commit 3ff574c5e1d1d5d07763a14f22d6f9d7291550c6)
---
 sys/ufs/ufs/ufs_vnops.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sys/ufs/ufs/ufs_vnops.c b/sys/ufs/ufs/ufs_vnops.c
index 949e7bcc1bec..954f85e17a9f 100644
--- a/sys/ufs/ufs/ufs_vnops.c
+++ b/sys/ufs/ufs/ufs_vnops.c
@@ -2434,8 +2434,10 @@ ufs_readdir(
        if (uio->uio_offset < 0)
                return (EINVAL);
        ip = VTOI(vp);
-       if (ip->i_effnlink == 0)
+       if (ip->i_effnlink == 0) {
+               *ap->a_eofflag = 1;
                return (0);
+       }
        if (ap->a_ncookies != NULL) {
                if (uio->uio_resid < 0)
                        ncookies = 0;