On 5/24/2024 12:17 PM, David Howells wrote:
Hi Christian,
Can you pick this up, please?
Thanks,
David
---
From: Marc Dionne<marc.dionne@xxxxxxxxxxxx>
afs: Don't cross .backup mountpoint from backup volume
Don't cross a mountpoint that explicitly specifies a backup volume
(target is <vol>.backup) when starting from a backup volume.
It it not uncommon to mount a volume's backup directly in the volume
itself. This can cause tools that are not paying attention to get
into a loop mounting the volume onto itself as they attempt to
traverse the tree, leading to a variety of problems.
This doesn't prevent the general case of loops in a sequence of
mountpoints, but addresses a common special case in the same way
as other afs clients.
Reported-by: Jan Henrik Sylvester<jan.henrik.sylvester@xxxxxxxxxxxxxx>
Link:http://lists.infradead.org/pipermail/linux-afs/2024-May/008454.html
Reported-by: Markus Suvanto<markus.suvanto@xxxxxxxxx>
Link:http://lists.infradead.org/pipermail/linux-afs/2024-February/008074.html
Signed-off-by: Marc Dionne<marc.dionne@xxxxxxxxxxxx>
Signed-off-by: David Howells<dhowells@xxxxxxxxxx>
Reviewed-by: Jeffrey Altman<jaltman@xxxxxxxxxxxx>
cc:linux-afs@xxxxxxxxxxxxxxxxxxx
---
fs/afs/mntpt.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c
index 97f50e9fd9eb..297487ee8323 100644
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -140,6 +140,11 @@ static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt)
put_page(page);
if (ret < 0)
return ret;
+
+ /* Don't cross a backup volume mountpoint from a backup volume */
+ if (src_as->volume && src_as->volume->type == AFSVL_BACKVOL &&
+ ctx->type == AFSVL_BACKVOL)
+ return -ENODEV;
}
return 0;
Please add
cc: stable@xxxxxxxxxxxxxxx
when it is applied to vfs-fixes.
Thank you.
Jeffrey Altman
