From 8dde90bca6fca3736ea20109654bcf6dcf2ecf1d Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 30 Oct 2018 10:41:41 +1100 Subject: vfs: remap helper should update destination inode metadata Extend generic_remap_file_range_prep to handle inode metadata updates when remapping into a file. If the operation can possibly alter the file contents, we must update the ctime and mtime and remove security privileges, just like we do for regular file writes. Signed-off-by: Darrick J. Wong Reviewed-by: Amir Goldstein Signed-off-by: Dave Chinner --- fs/read_write.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'fs/read_write.c') diff --git a/fs/read_write.c b/fs/read_write.c index ebcbfc4f2907..b61bd3fc7154 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1820,6 +1820,25 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, if (ret) return ret; + /* If can't alter the file contents, we're done. */ + if (!(remap_flags & REMAP_FILE_DEDUP)) { + /* Update the timestamps, since we can alter file contents. */ + if (!(file_out->f_mode & FMODE_NOCMTIME)) { + ret = file_update_time(file_out); + if (ret) + return ret; + } + + /* + * Clear the security bits if the process is not being run by + * root. This keeps people from modifying setuid and setgid + * binaries. + */ + ret = file_remove_privs(file_out); + if (ret) + return ret; + } + return 1; } EXPORT_SYMBOL(generic_remap_file_range_prep); -- cgit