Re: [PATCH v3 0/7] File Sealing & memfd_create()
From: Andy Lutomirski <luto@amacapital.net>
Date: 2014-06-13 15:10:57
Also in:
linux-fsdevel, linux-mm, lkml
On Fri, Jun 13, 2014 at 3:36 AM, David Herrmann [off-list ref] wrote:
Hi This is v3 of the File-Sealing and memfd_create() patches. You can find v1 with a longer introduction at gmane: http://thread.gmane.org/gmane.comp.video.dri.devel/102241 An LWN article about memfd+sealing is available, too: https://lwn.net/Articles/593918/ v2 with some more discussions can be found here: http://thread.gmane.org/gmane.linux.kernel.mm/115713 This series introduces two new APIs: memfd_create(): Think of this syscall as malloc() but it returns a file-descriptor instead of a pointer. That file-descriptor is backed by anon-memory and can be memory-mapped for access. sealing: The sealing API can be used to prevent a specific set of operations on a file-descriptor. You 'seal' the file and give thus the guarantee, that it cannot be modified in the specific ways. A short high-level introduction is also available here: http://dvdhrm.wordpress.com/2014/06/10/memfd_create2/
Potentially silly question: is it guaranteed that mmapping and reading a SEAL_SHRINKed fd within size bounds will not SIGBUS? If so, should this be documented? (The particular issue here would be reading holes. It should work by using the zero page, but, if so, we should probably make it a real documented guarantee.) --Andy -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>