On Wed, Mar 29, 2017 at 11:44 PM, Tommi Rantala <[email protected]> wrote: > Hi, > > Running: > > $ sudo x86info -a > > On this HP ZBook 15 G3 laptop kills the x86info process with segfault and > produces the following kernel BUG. > > $ git describe > v4.11-rc4-40-gfe82203 > > It is also reproducible with the fedora kernel: 4.9.14-200.fc25.x86_64 > > Full dmesg output here: https://pastebin.com/raw/Kur2mpZq > > [ 51.418954] usercopy: kernel memory exposure attempt detected from > ffff880000090000 (dma-kmalloc-256) (4096 bytes)
This seems like a real exposure: the copy is attempting to read 4096 bytes from a 256 byte object. > [...] > [ 51.419063] Call Trace: > [ 51.419066] read_mem+0x70/0x120 > [ 51.419069] __vfs_read+0x28/0x130 > [ 51.419072] ? security_file_permission+0x9b/0xb0 > [ 51.419075] ? rw_verify_area+0x4e/0xb0 > [ 51.419077] vfs_read+0x96/0x130 > [ 51.419079] SyS_read+0x46/0xb0 > [ 51.419082] ? SyS_lseek+0x87/0xb0 > [ 51.419085] entry_SYSCALL_64_fastpath+0x1a/0xa9 I can't reproduce this myself, so I assume it's some specific /proc or /sys file that I don't have. Are you able to get a strace of x86info as it runs to see which file it is attempting to read here? Thanks! -Kees -- Kees Cook Pixel Security
