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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id 19sm5414686pgg.36.2021.07.27.14.06.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jul 2021 14:07:01 -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 50/64] KVM: x86: Use struct_group() to zero decode cache Date: Tue, 27 Jul 2021 13:58:41 -0700 Message-Id: <20210727205855.411487-51-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> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1896; h=from:subject; bh=Yy2yFM1urtqhL7n0r4aqd2cxgBZVMAyveJbcFvHLMlI=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBhAHOLO3D9COdGLWOeR85zbaklAzObwkj15dNUWB7V d7VJAUWJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYQBziwAKCRCJcvTf3G3AJlCqD/ 9cyHvgurMj0+H5UBZbi3PT0Pbs8SRpr/t0XADG40BpZ+yVAAnrqFDSkxMwCaBqoxRSLdmcDqy3b5SU c20S1Aw1siyqHiVEI4mnsKY6Jgrwx/SMBp2bYIVeZru9HNSXKKx57kdf2tIrViE9LYxYJFaHrBwPb9 o5tiJQmaA6MIjjExAe20o1QhTaI/E8sNfmlXtKaS0+XA7Rm8s+Qw65FVDyLqzv2BWb50Hdr4cMYh1X MTXkpiMZrMaPEQ3Wa2TwW0eAlAoWXXUXCLZ9VWJ5QlWKljXrylcdoLAikqEE7v2J5Rlr6FXOAMs3tZ d2CLoMo36Px3zBdTlu90/UlVPgO3P/Uk2ZhkN4uzHd4n/DIvanRvGewXH4liErXPixMmOgnLGLl+5d dVxT4PdjmU6shd83BEuZ8GZH4T6M9tygTNcERhWYIFMPXxYO5sgBrAlOJPmGkJC7hJD/RcfcYrBrpN UanrlQrhn6AYQGnmxcAQjc9dQQiRJO+jcDS4dRElaZb2OkRAD8J6+dNCu3El0L2RSWF1CiAbnwjwZi vxQaozruf1DsPdfg+Bv8JNonOrCpc7rnWMUbZIM6n0KMZJB+puj15D3L2N22fwOUi7MkF9cUWlAzlk H8X7oTv0jAj5RR0KuG/re2JSTLAEqtF1EBsbI72rE8m6mO5OjrH8edIe/qDg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Add struct_group() to mark region of struct x86_emulate_ctxt that should be initialized to zero. Signed-off-by: Kees Cook --- arch/x86/kvm/emulate.c | 3 +-- arch/x86/kvm/kvm_emulate.h | 19 +++++++++++-------- 2 files changed, 12 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 2837110e66ed..2608a047e769 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5377,8 +5377,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop) void init_decode_cache(struct x86_emulate_ctxt *ctxt) { - memset(&ctxt->rip_relative, 0, - (void *)&ctxt->modrm - (void *)&ctxt->rip_relative); + memset(&ctxt->decode_cache, 0, sizeof(ctxt->decode_cache)); ctxt->io_read.pos = 0; ctxt->io_read.end = 0; diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index 68b420289d7e..9b8afcb8ad39 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -341,14 +341,17 @@ struct x86_emulate_ctxt { * the rest are initialized unconditionally in x86_decode_insn * or elsewhere */ - bool rip_relative; - u8 rex_prefix; - u8 lock_prefix; - u8 rep_prefix; - /* bitmaps of registers in _regs[] that can be read */ - u32 regs_valid; - /* bitmaps of registers in _regs[] that have been written */ - u32 regs_dirty; + struct_group(decode_cache, + bool rip_relative; + u8 rex_prefix; + u8 lock_prefix; + u8 rep_prefix; + /* bitmaps of registers in _regs[] that can be read */ + u32 regs_valid; + /* bitmaps of registers in _regs[] that have been written */ + u32 regs_dirty; + ); + /* modrm */ u8 modrm; u8 modrm_mod; -- 2.30.2