git: 155987e20190 - stable/14 - tarfs: Fix the size of struct tarfs_fid and add a static assert

[Olivier Certner]

The branch stable/14 has been updated by olce:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=155987e2019089a5bd2eef77ed7bcc5cc26c362e

commit 155987e2019089a5bd2eef77ed7bcc5cc26c362e
Author:     Rick Macklem <rmack...@freebsd.org>
AuthorDate: 2024-12-06 02:09:27 +0000
Commit:     Olivier Certner <o...@freebsd.org>
CommitDate: 2025-01-17 13:50:46 +0000

    tarfs: Fix the size of struct tarfs_fid and add a static assert
    
    File system specific *fid structures are copied into the generic
    struct fid defined in sys/mount.h.
    As such, they cannot be larger than struct fid.
    
    This patch packs the structure and checks via a __Static_assert().
    
    Reviewed by:    markj
    MFC after:      2 weeks
    
    (cherry picked from commit 4db1b113b15158c7d134df83e7a7201cf46d459b)
---
 sys/fs/tarfs/tarfs.h       | 2 +-
 sys/fs/tarfs/tarfs_vnops.c | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/sys/fs/tarfs/tarfs.h b/sys/fs/tarfs/tarfs.h
index ff1985e488cd..ffb95d2c0ac5 100644
--- a/sys/fs/tarfs/tarfs.h
+++ b/sys/fs/tarfs/tarfs.h
@@ -165,7 +165,7 @@ struct tarfs_fid {
        u_short                  data0; /* force alignment */
        ino_t                    ino;
        unsigned long            gen;
-};
+} __packed;
 
 #define        TARFS_NODE_LOCK(tnp) \
        mtx_lock(&(tnp)->lock)
diff --git a/sys/fs/tarfs/tarfs_vnops.c b/sys/fs/tarfs/tarfs_vnops.c
index 8c97fab185fc..afb8e05f5929 100644
--- a/sys/fs/tarfs/tarfs_vnops.c
+++ b/sys/fs/tarfs/tarfs_vnops.c
@@ -668,6 +668,8 @@ tarfs_vptofh(struct vop_vptofh_args *ap)
 {
        struct tarfs_fid *tfp;
        struct tarfs_node *tnp;
+       _Static_assert(sizeof(struct tarfs_fid) <= sizeof(struct fid),
+           "struct tarfs_fid cannot be larger than struct fid");
 
        tfp = (struct tarfs_fid *)ap->a_fhp;
        tnp = VP_TO_TARFS_NODE(ap->a_vp);