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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id i1sm4395555pfo.37.2021.07.27.14.06.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jul 2021 14:06:55 -0700 (PDT) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , "Gustavo A. R. Silva" , Keith Packard , Greg Kroah-Hartman , Andrew Morton , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-staging@lists.linux.dev, linux-block@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com Subject: [PATCH 38/64] xfrm: Use memset_after() to clear padding Date: Tue, 27 Jul 2021 13:58:29 -0700 Message-Id: <20210727205855.411487-39-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210727205855.411487-1-keescook@chromium.org> References: <20210727205855.411487-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1608; h=from:subject; bh=g0VWO37QK3XIcvkgv5p13lDa7YD+Jvxsuneh5al+DKo=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBhAHOIQmnrWwAaxPVdj8lblXkb8ZdEI/mjJwkI9weg Jb9tdxuJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYQBziAAKCRCJcvTf3G3AJkUiD/ 9GVAFoJywTVZLGJMfv82icJWJQRMDO1fnyc7Vo6lQ1D7/W+Dagrov588jsfphYxw9bCcMrBW5+ML39 Nlw0d86SRJKsp9W1D/uWpxT7B+ZifwMCrBQiW/QQdugvpBK16DiM/nuIxmvvNngfCD7TZeYhnxyJCN Q8sbUMZx2T8aExzVPglAhsAqyZAACXNIyRAkJJKyEFCtk5DV7xNyz4H7EIco1PaNQ6CPSvz3qtegIn nv2P2319IG2VLE3I2NZVINSDUfhFT63odWJElKoysAbPDvrq3781fUtYESiohGHqBR8FD3BGT+O8y5 9KD6fIZ0TSLsD63axSBtgp5OUer7kr086Bp7sU1ndEXv436bquzOxnCxGOOZ82tsCGeW/VxkIdKzGd IqrtSepbn6JZoMYp10wQJpM6ZcvscK8K2zcp2RMRpDMku/9dFd2GQ45TO3uUh94594qJDdQG0ecNlA NIP+5MnO4vD6X6sONnGwoom7JbHdfvLOAg4vRaXZ2jfmckTzxmeUil4NB16b45RGMUUNbmfDrGgLJc 0oHx1OYHLUpyYpWBvqH49SivknOgZOZzXIyabXPipERmCdfnqRmLJeBYq67aP5IvRZgUVF848zQS1a wYduCIDFnUzR+Pq8e8OGT0DcZ9ZGKEr3Av8YeNoVe5GpEviziiQ3/Fj3WyIg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Clear trailing padding bytes using the new helper so that memset() doesn't get confused about writing "past the end" of the last struct member. There is no change to the resulting machine code. Signed-off-by: Kees Cook --- net/xfrm/xfrm_policy.c | 4 +--- net/xfrm/xfrm_user.c | 2 +- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 37d17a79617c..1a06585022ab 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -2486,9 +2486,7 @@ static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family) xdst = dst_alloc(dst_ops, NULL, 1, DST_OBSOLETE_NONE, 0); if (likely(xdst)) { - struct dst_entry *dst = &xdst->u.dst; - - memset(dst + 1, 0, sizeof(*xdst) - sizeof(*dst)); + memset_after(xdst, 0, u.dst); } else xdst = ERR_PTR(-ENOBUFS); diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index acc3a0dab331..0bf8fec3fd97 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -2907,7 +2907,7 @@ static int build_expire(struct sk_buff *skb, struct xfrm_state *x, const struct copy_to_user_state(x, &ue->state); ue->hard = (c->data.hard != 0) ? 1 : 0; /* clear the padding bytes */ - memset(&ue->hard + 1, 0, sizeof(*ue) - offsetofend(typeof(*ue), hard)); + memset_after(ue, 0, hard); err = xfrm_mark_put(skb, &x->mark); if (err)