Patch "bpf, ppc64: fix out of bounds access in tail call" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    bpf, ppc64: fix out of bounds access in tail call

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Fri Mar  9 14:20:51 PST 2018
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu,  8 Mar 2018 16:17:37 +0100
Subject: bpf, ppc64: fix out of bounds access in tail call
To: gregkh@linuxfoundation.org
Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org
Message-ID: <08bc9e5902de0e9e9b26194ba4ea219f053b7206.1520521792.git.daniel@iogearbox.net>

From: Daniel Borkmann <daniel@iogearbox.net>

[ upstream commit d269176e766c71c998cb75b4ea8cbc321cc0019d ]

While working on 16338a9b3ac3 ("bpf, arm64: fix out of bounds access in
tail call") I noticed that ppc64 JIT is partially affected as well. While
the bound checking is correctly performed as unsigned comparison, the
register with the index value however, is never truncated into 32 bit
space, so e.g. a index value of 0x100000000ULL with a map of 1 element
would pass with PPC_CMPLW() whereas we later on continue with the full
64 bit register value. Therefore, as we do in interpreter and other JITs
truncate the value to 32 bit initially in order to fix access.

Fixes: ce0761419fae ("powerpc/bpf: Implement support for tail calls")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/powerpc/net/bpf_jit_comp64.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -245,6 +245,7 @@ static void bpf_jit_emit_tail_call(u32 *
 	 *   goto out;
 	 */
 	PPC_LWZ(b2p[TMP_REG_1], b2p_bpf_array, offsetof(struct bpf_array, map.max_entries));
+	PPC_RLWINM(b2p_index, b2p_index, 0, 0, 31);
 	PPC_CMPLW(b2p_index, b2p[TMP_REG_1]);
 	PPC_BCC(COND_GE, out);
 


Patches currently in stable-queue which might be from daniel@iogearbox.net are

queue-4.9/bpf-fix-mlock-precharge-on-arraymaps.patch
queue-4.9/bpf-x64-implement-retpoline-for-tail-call.patch
queue-4.9/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.9/bpf-fix-wrong-exposure-of-map_flags-into-fdinfo-for-lpm.patch
queue-4.9/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch
queue-4.9/bpf-add-schedule-points-in-percpu-arrays-management.patch