From: Chao Yu yuchao0@huawei.com
commit e0fcd01510ad025c9bbce704c5c2579294056141 upstream.
This patch ports commit 02b016ca7f99 ("ext4: enforce the immutable flag on open files") to f2fs.
According to the chattr man page, "a file with the 'i' attribute cannot be modified..." Historically, this was only enforced when the file was opened, per the rest of the description, "... and the file can not be opened in write mode".
There is general agreement that we should standardize all file systems to prevent modifications even for files that were opened at the time the immutable flag is set. Eventually, a change to enforce this at the VFS layer should be landing in mainline.
Cc: stable@kernel.org Signed-off-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/f2fs/file.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
--- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -60,6 +60,9 @@ static vm_fault_t f2fs_vm_page_mkwrite(s bool need_alloc = true; int err = 0;
+ if (unlikely(IS_IMMUTABLE(inode))) + return VM_FAULT_SIGBUS; + if (unlikely(f2fs_cp_error(sbi))) { err = -EIO; goto err; @@ -870,6 +873,14 @@ int f2fs_setattr(struct dentry *dentry, if (unlikely(f2fs_cp_error(F2FS_I_SB(inode)))) return -EIO;
+ if (unlikely(IS_IMMUTABLE(inode))) + return -EPERM; + + if (unlikely(IS_APPEND(inode) && + (attr->ia_valid & (ATTR_MODE | ATTR_UID | + ATTR_GID | ATTR_TIMES_SET)))) + return -EPERM; + if ((attr->ia_valid & ATTR_SIZE) && !f2fs_is_compress_backend_ready(inode)) return -EOPNOTSUPP; @@ -4356,6 +4367,11 @@ static ssize_t f2fs_file_write_iter(stru inode_lock(inode); }
+ if (unlikely(IS_IMMUTABLE(inode))) { + ret = -EPERM; + goto unlock; + } + ret = generic_write_checks(iocb, from); if (ret > 0) { bool preallocated = false; @@ -4420,6 +4436,7 @@ write: if (ret > 0) f2fs_update_iostat(F2FS_I_SB(inode), APP_WRITE_IO, ret); } +unlock: inode_unlock(inode); out: trace_f2fs_file_write_iter(inode, iocb->ki_pos,