linux/arch/powerpc
Nicholas Piggin f62f3c2064 KVM: PPC: Book3S: Fix H_RTAS rets buffer overflow
The kvmppc_rtas_hcall() sets the host rtas_args.rets pointer based on
the rtas_args.nargs that was provided by the guest. That guest nargs
value is not range checked, so the guest can cause the host rets pointer
to be pointed outside the args array. The individual rtas function
handlers check the nargs and nrets values to ensure they are correct,
but if they are not, the handlers store a -3 (0xfffffffd) failure
indication in rets[0] which corrupts host memory.

Fix this by testing up front whether the guest supplied nargs and nret
would exceed the array size, and fail the hcall directly without storing
a failure indication to rets[0].

Also expand on a comment about why we kill the guest and try not to
return errors directly if we have a valid rets[0] pointer.

Fixes: 8e591cb720 ("KVM: PPC: Book3S: Add infrastructure to implement kernel-side RTAS calls")
Cc: stable@vger.kernel.org # v3.10+
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2021-07-23 16:14:31 +10:00
..
boot powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
configs TTY / Serial patches for 5.14-rc1 2021-07-05 14:08:24 -07:00
crypto
include powerpc/book3s64/mm: update flush_tlb_range to flush page walk cache 2021-07-08 11:48:23 -07:00
kernel powerpc fixes for 5.14 #2 2021-07-09 10:26:52 -07:00
kexec powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
kvm KVM: PPC: Book3S: Fix H_RTAS rets buffer overflow 2021-07-23 16:14:31 +10:00
lib powerpc: Only build restart_table.c for 64s 2021-07-01 22:50:54 +10:00
math-emu powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
mm powerpc fixes for 5.14 #2 2021-07-09 10:26:52 -07:00
net powerpc/bpf: Reject atomic ops in ppc32 JIT 2021-07-05 22:23:25 +10:00
perf powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
platforms powerpc fixes for 5.14 #2 2021-07-09 10:26:52 -07:00
purgatory
sysdev powerpc/xive: Fix error handling when allocating an IPI 2021-07-05 22:23:25 +10:00
tools
xmon powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
Kbuild
Kconfig powerpc updates for 5.14 2021-07-02 12:54:34 -07:00
Kconfig.debug powerpc: Make PPC_IRQ_SOFT_MASK_DEBUG depend on PPC64 2021-06-25 00:07:09 +10:00
Makefile Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
Makefile.postlink