git: 4b737a9c58ca - releng/13.0 - pgcache read: protect against reads past end of the vm object size

[Konstantin Belousov]

The branch releng/13.0 has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=4b737a9c58cac69008f189cc44e7d1a81a0b601c

commit 4b737a9c58cac69008f189cc44e7d1a81a0b601c
Author:     Konstantin Belousov <kib at FreeBSD.org>
AuthorDate: 2021-02-15 03:34:06 +0000
Commit:     Konstantin Belousov <kib at FreeBSD.org>
CommitDate: 2021-02-23 11:21:00 +0000

    pgcache read: protect against reads past end of the vm object size
    
    PR:     253158
    Approved by:    re (gjb)
    
    (cherry picked from commit c61fae1475f1864dc4bba667b642f279afd44855)
---
 sys/kern/vfs_vnops.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index 6c6727c7f372..1e52a797a1f7 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -951,6 +951,10 @@ vn_read_from_obj(struct vnode *vp, struct uio *uio)
 #else
 	vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size);
 #endif
+	if (uio->uio_offset >= vsz) {
+		error = EJUSTRETURN;
+		goto out;
+	}
 	if (uio->uio_offset + resid > vsz)
 		resid = vsz - uio->uio_offset;