From df7fdcfcbf394da72548f74147b3442a01914185 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Wed, 24 Mar 2021 11:57:43 +0900 Subject: [PATCH] exfat: attr: handle idmapped mounts When file attributes are changed most filesystems rely on the setattr_prepare(), setattr_copy(), and notify_change() helpers for initialization and permission checking. Let them handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Helpers that perform checks on the ia_uid and ia_gid fields in struct iattr assume that ia_uid and ia_gid are intended values and have already been mapped correctly at the userspace-kernelspace boundary as we already do today. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner Signed-off-by: Namjae Jeon --- file.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/file.c b/file.c index 37e013cff2e2..858a454d5827 100644 --- a/file.c +++ b/file.c @@ -344,7 +344,11 @@ int exfat_setattr(struct dentry *dentry, struct iattr *attr) #if ((LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)) && \ (LINUX_VERSION_CODE >= KERNEL_VERSION(4, 1, 37))) || \ (LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)) +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 12, 0) + error = setattr_prepare(&init_user_ns, dentry, attr); +#else error = setattr_prepare(dentry, attr); +#endif #else error = inode_change_ok(inode, attr); #endif @@ -382,7 +386,11 @@ int exfat_setattr(struct dentry *dentry, struct iattr *attr) up_write(&EXFAT_I(inode)->truncate_lock); } +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 12, 0) + setattr_copy(&init_user_ns, inode, attr); +#else setattr_copy(inode, attr); +#endif exfat_truncate_atime(&inode->i_atime); mark_inode_dirty(inode);