Date: Wed, 10 May 2023 19:07:10 +0200 From: Solar Designer <solar@...nwall.com> To: oss-security@...ts.openwall.com Cc: Tobias Holl <tobias@...ll.xyz> Subject: Re: Linux kernel io_uring out-of-bounds access to physical memory On Mon, May 08, 2023 at 04:01:59PM +0200, Tobias Holl wrote: > TL;DR bug reproduction steps: > 1. Create a memfd > 2. fallocate a single page in that file descriptor > 3. Use MAP_FIXED to map this page repeatedly, in consecutive locations > 4. Register the entire region that you just filled up with that page as > a fixed buffer with IORING_REGISTER_BUFFERS > 5. Use IORING_OP_WRITE_FIXED to write the buffer to some other file > (OOB read) or IORING_OP_READ_FIXED to read data into the buffer (OOB > write). > > Of course, from there, we can simply find any interesting object in > physical memory and start overwriting function pointers to get code > execution and escalate privileges. A full proof-of-concept exploit with > a bit more robustness can be found at > https://tholl.xyz/static/bugs/2023-io_uring-fixed-buffers/exploit.c I initially overlooked that the exploit was only shared by reference. Let's have it right in here for archival. Attached. Alexander View attachment "exploit.c" of type "text/x-c" (25512 bytes)
Powered by blists - more mailing lists
Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.