[PATCH AUTOSEL 6.11 49/76] fuse: handle idmappings properly in ->write_iter()

Sasha Levin
2024-10-04T18:19:59Z

From: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>

[ Upstream commit 5b8ca5a54cb89ab07b0389f50e038e533cdfdd86 ]

This is needed to properly clear suid/sgid.

Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/fuse/file.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index ed76121f73f2e..536194d41b0b7 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1398,6 +1398,7 @@ static void fuse_dio_unlock(struct kiocb *iocb, bool exclusive)
static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
+ struct mnt_idmap *idmap = file_mnt_idmap(file);
struct address_space *mapping = file->f_mapping;
ssize_t written = 0;
struct inode *inode = mapping->host;
@@ -1412,7 +1413,7 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
return err;

if (fc->handle_killpriv_v2 &&
- setattr_should_drop_suidgid(&nop_mnt_idmap,
+ setattr_should_drop_suidgid(idmap,
file_inode(file))) {
goto writethrough;
}
--
2.43.0