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

mpls, nospec: Sanitize array index in mpls_label_ok()

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: mpls-nospec-sanitize-array-index-in-mpls_label_ok.patch and it can be found in the queue-4.14 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 3968523f855050b8195134da951b87c20bd66130 Mon Sep 17 00:00:00 2001

From: Dan Williams dan.j.williams@intel.com Date: Wed, 7 Feb 2018 22:34:24 -0800 Subject: mpls, nospec: Sanitize array index in mpls_label_ok()

From: Dan Williams dan.j.williams@intel.com

commit 3968523f855050b8195134da951b87c20bd66130 upstream.

mpls_label_ok() validates that the 'platform_label' array index from a userspace netlink message payload is valid. Under speculation the mpls_label_ok() result may not resolve in the CPU pipeline until after the index is used to access an array element. Sanitize the index to zero to prevent userspace-controlled arbitrary out-of-bounds speculation, a precursor for a speculative execution side channel vulnerability.

Cc: stable@vger.kernel.org Cc: "David S. Miller" davem@davemloft.net Cc: Eric W. Biederman ebiederm@xmission.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- net/mpls/af_mpls.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)

--- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -8,6 +8,7 @@ #include <linux/ipv6.h> #include <linux/mpls.h> #include <linux/netconf.h> +#include <linux/nospec.h> #include <linux/vmalloc.h> #include <linux/percpu.h> #include <net/ip.h> @@ -904,24 +905,27 @@ errout: return err; }

-static bool mpls_label_ok(struct net *net, unsigned int index, +static bool mpls_label_ok(struct net *net, unsigned int *index, struct netlink_ext_ack *extack) { + bool is_ok = true; + /* Reserved labels may not be set */ - if (index < MPLS_LABEL_FIRST_UNRESERVED) { + if (*index < MPLS_LABEL_FIRST_UNRESERVED) { NL_SET_ERR_MSG(extack, "Invalid label - must be MPLS_LABEL_FIRST_UNRESERVED or higher"); - return false; + is_ok = false; }

/* The full 20 bit range may not be supported. */ - if (index >= net->mpls.platform_labels) { + if (is_ok && *index >= net->mpls.platform_labels) { NL_SET_ERR_MSG(extack, "Label >= configured maximum in platform_labels"); - return false; + is_ok = false; }

- return true; + *index = array_index_nospec(*index, net->mpls.platform_labels); + return is_ok; }

static int mpls_route_add(struct mpls_route_config *cfg, @@ -944,7 +948,7 @@ static int mpls_route_add(struct mpls_ro index = find_free_label(net); }

- if (!mpls_label_ok(net, index, extack)) + if (!mpls_label_ok(net, &index, extack)) goto errout;

/* Append makes no sense with mpls */ @@ -1021,7 +1025,7 @@ static int mpls_route_del(struct mpls_ro

index = cfg->rc_label;

- if (!mpls_label_ok(net, index, extack)) + if (!mpls_label_ok(net, &index, extack)) goto errout;

mpls_route_update(net, index, NULL, &cfg->rc_nlinfo); @@ -1779,7 +1783,7 @@ static int rtm_to_route_config(struct sk goto errout;

if (!mpls_label_ok(cfg->rc_nlinfo.nl_net, - cfg->rc_label, extack)) + &cfg->rc_label, extack)) goto errout; break; } @@ -2106,7 +2110,7 @@ static int mpls_getroute(struct sk_buff goto errout; }

- if (!mpls_label_ok(net, in_label, extack)) { + if (!mpls_label_ok(net, &in_label, extack)) { err = -EINVAL; goto errout; }

Patches currently in stable-queue which might be from dan.j.williams@intel.com are

queue-4.14/x86-entry-64-interleave-xor-register-clearing-with-push-instructions.patch queue-4.14/nospec-move-array_index_nospec-parameter-checking-into-separate-macro.patch queue-4.14/x86-entry-64-merge-the-pop_c_regs-and-pop_extra_regs-macros-into-a-single-pop_regs-macro.patch queue-4.14/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.14/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.14/x86-speculation-add-asm-msr-index.h-dependency.patch queue-4.14/mm-fix-memory-size-alignment-in-devm_memremap_pages_release.patch queue-4.14/x86-entry-64-use-push_and_clean_regs-in-more-cases.patch queue-4.14/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.14/x86-entry-64-clear-registers-for-exceptions-interrupts-to-reduce-speculation-attack-surface.patch queue-4.14/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch queue-4.14/x86-entry-64-merge-save_c_regs-and-save_extra_regs-remove-unused-extensions.patch queue-4.14/x86-entry-64-indent-push_and_clear_regs-and-pop_regs-properly.patch queue-4.14/x86-speculation-fix-up-array_index_nospec_mask-asm-constraint.patch queue-4.14/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch queue-4.14/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.14/x86-mm-pti-fix-pti-comment-in-entry_syscall_64.patch queue-4.14/x86-entry-64-get-rid-of-the-alloc_pt_gpregs_on_stack-and-save_and_clear_regs-macros.patch queue-4.14/mpls-nospec-sanitize-array-index-in-mpls_label_ok.patch queue-4.14/x86-speculation-clean-up-various-spectre-related-details.patch queue-4.14/x86-entry-64-introduce-the-push_and_clean_regs-macro.patch queue-4.14/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch queue-4.14/x86-entry-64-compat-clear-registers-for-compat-syscalls-to-reduce-speculation-attack-surface.patch queue-4.14/x86-entry-64-fix-cr3-restore-in-paranoid_exit.patch