linux/arch
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
..
alpha Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
arc Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
arm Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
arm64 Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
csky Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
h8300 Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
hexagon Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
ia64 Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
m68k Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
microblaze Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
mips Two fixes: 2021-07-11 11:17:57 -07:00
nds32 Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
nios2 Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
openrisc Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
parisc Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
powerpc KVM: PPC: Book3S: Fix H_RTAS rets buffer overflow 2021-07-23 16:14:31 +10:00
riscv Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
s390 Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
sh Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
sparc Locking fixes: 2021-07-11 11:06:09 -07:00
um Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
x86 A fix and a hardware-enablement addition: 2021-07-11 11:10:48 -07:00
xtensa Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
.gitignore
Kconfig Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR 2021-06-22 11:07:18 -07:00