https://github.com/torvalds/linux
Revision c995f12ad8842dbf5cfed113fb52cdd083f5afd1 authored by Alexey Dobriyan on 14 March 2021, 20:51:14 UTC, committed by Linus Torvalds on 14 March 2021, 21:33:27 UTC
Doing a

	prctl(PR_SET_MM, PR_SET_MM_AUXV, addr, 1);

will copy 1 byte from userspace to (quite big) on-stack array
and then stash everything to mm->saved_auxv.
AT_NULL terminator will be inserted at the very end.

/proc/*/auxv handler will find that AT_NULL terminator
and copy original stack contents to userspace.

This devious scheme requires CAP_SYS_RESOURCE.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 70404fe
History
Tip revision: c995f12ad8842dbf5cfed113fb52cdd083f5afd1 authored by Alexey Dobriyan on 14 March 2021, 20:51:14 UTC
prctl: fix PR_SET_MM_AUXV kernel stack leak
Tip revision: c995f12
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