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Mon, 19 Sep 2022 12:16:22 +0200 (CEST) Message-ID: <20220919101523.177759249@infradead.org> User-Agent: quilt/0.66 Date: Mon, 19 Sep 2022 12:00:21 +0200 From: Peter Zijlstra To: peterz@infradead.org Cc: richard.henderson@linaro.org, ink@jurassic.park.msu.ru, mattst88@gmail.com, vgupta@kernel.org, linux@armlinux.org.uk, ulli.kroll@googlemail.com, linus.walleij@linaro.org, shawnguo@kernel.org, Sascha Hauer , kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com, tony@atomide.com, khilman@kernel.org, catalin.marinas@arm.com, will@kernel.org, guoren@kernel.org, bcain@quicinc.com, chenhuacai@kernel.org, kernel@xen0n.name, geert@linux-m68k.org, sammy@sammy.net, monstr@monstr.eu, tsbogend@alpha.franken.de, dinguyen@kernel.org, jonas@southpole.se, stefan.kristiansson@saunalahti.fi, shorne@gmail.com, James.Bottomley@HansenPartnership.com, deller@gmx.de, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, ysato@users.sourceforge.jp, dalias@libc.org, davem@davemloft.net, richard@nod.at, anton.ivanov@cambridgegreys.com, johannes@sipsolutions.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, jgross@suse.com, srivatsa@csail.mit.edu, amakhalov@vmware.com, pv-drivers@vmware.com, boris.ostrovsky@oracle.com, chris@zankel.net, jcmvbkbc@gmail.com, rafael@kernel.org, lenb@kernel.org, pavel@ucw.cz, gregkh@linuxfoundation.org, mturquette@baylibre.com, sboyd@kernel.org, daniel.lezcano@linaro.org, lpieralisi@kernel.org, sudeep.holla@arm.com, agross@kernel.org, bjorn.andersson@linaro.org, konrad.dybcio@somainline.org, anup@brainfault.org, thierry.reding@gmail.com, jonathanh@nvidia.com, jacob.jun.pan@linux.intel.com, atishp@atishpatra.org, Arnd Bergmann , yury.norov@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, dennis@kernel.org, tj@kernel.org, cl@linux.com, rostedt@goodmis.org, pmladek@suse.com, senozhatsky@chromium.org, john.ogness@linutronix.de, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, fweisbec@gmail.com, ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, Andrew Morton , jpoimboe@kernel.org, linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-omap@vger.kernel.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-perf-users@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-xtensa@linux-xtensa.org, linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-tegra@vger.kernel.org, linux-arch@vger.kernel.org, kasan-dev@googlegroups.com Subject: [PATCH v2 42/44] entry,kasan,x86: Disallow overriding mem*() functions References: <20220919095939.761690562@infradead.org> MIME-Version: 1.0 X-Mailman-Approved-At: Mon, 19 Sep 2022 08:09:27 -0700 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org KASAN cannot just hijack the mem*() functions, it needs to emit __asan_mem*() variants if it wants instrumentation (other sanitizers already do this). vmlinux.o: warning: objtool: sync_regs+0x24: call to memcpy() leaves .noinstr.text section vmlinux.o: warning: objtool: vc_switch_off_ist+0xbe: call to memcpy() leaves .noinstr.text section vmlinux.o: warning: objtool: fixup_bad_iret+0x36: call to memset() leaves .noinstr.text section vmlinux.o: warning: objtool: __sev_get_ghcb+0xa0: call to memcpy() leaves .noinstr.text section vmlinux.o: warning: objtool: __sev_put_ghcb+0x35: call to memcpy() leaves .noinstr.text section Remove the weak aliases to ensure nobody hijacks these functions and add them to the noinstr section. Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/lib/memcpy_64.S | 5 ++--- arch/x86/lib/memmove_64.S | 4 +++- arch/x86/lib/memset_64.S | 4 +++- mm/kasan/kasan.h | 4 ++++ mm/kasan/shadow.c | 38 ++++++++++++++++++++++++++++++++++++++ tools/objtool/check.c | 3 +++ 6 files changed, 53 insertions(+), 5 deletions(-) --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -7,7 +7,7 @@ #include #include -.pushsection .noinstr.text, "ax" +.section .noinstr.text, "ax" /* * We build a jump to memcpy_orig by default which gets NOPped out on @@ -42,7 +42,7 @@ SYM_FUNC_START(__memcpy) SYM_FUNC_END(__memcpy) EXPORT_SYMBOL(__memcpy) -SYM_FUNC_ALIAS_WEAK(memcpy, __memcpy) +SYM_FUNC_ALIAS(memcpy, __memcpy) EXPORT_SYMBOL(memcpy) /* @@ -183,4 +183,3 @@ SYM_FUNC_START_LOCAL(memcpy_orig) RET SYM_FUNC_END(memcpy_orig) -.popsection --- a/arch/x86/lib/memmove_64.S +++ b/arch/x86/lib/memmove_64.S @@ -13,6 +13,8 @@ #undef memmove +.section .noinstr.text, "ax" + /* * Implement memmove(). This can handle overlap between src and dst. * @@ -213,5 +215,5 @@ SYM_FUNC_START(__memmove) SYM_FUNC_END(__memmove) EXPORT_SYMBOL(__memmove) -SYM_FUNC_ALIAS_WEAK(memmove, __memmove) +SYM_FUNC_ALIAS(memmove, __memmove) EXPORT_SYMBOL(memmove) --- a/arch/x86/lib/memset_64.S +++ b/arch/x86/lib/memset_64.S @@ -6,6 +6,8 @@ #include #include +.section .noinstr.text, "ax" + /* * ISO C memset - set a memory block to a byte value. This function uses fast * string to get better performance than the original function. The code is @@ -43,7 +45,7 @@ SYM_FUNC_START(__memset) SYM_FUNC_END(__memset) EXPORT_SYMBOL(__memset) -SYM_FUNC_ALIAS_WEAK(memset, __memset) +SYM_FUNC_ALIAS(memset, __memset) EXPORT_SYMBOL(memset) /* --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -551,6 +551,10 @@ void __asan_set_shadow_f3(const void *ad void __asan_set_shadow_f5(const void *addr, size_t size); void __asan_set_shadow_f8(const void *addr, size_t size); +void *__asan_memset(void *addr, int c, size_t len); +void *__asan_memmove(void *dest, const void *src, size_t len); +void *__asan_memcpy(void *dest, const void *src, size_t len); + void __hwasan_load1_noabort(unsigned long addr); void __hwasan_store1_noabort(unsigned long addr); void __hwasan_load2_noabort(unsigned long addr); --- a/mm/kasan/shadow.c +++ b/mm/kasan/shadow.c @@ -38,6 +38,12 @@ bool __kasan_check_write(const volatile } EXPORT_SYMBOL(__kasan_check_write); +#ifndef CONFIG_GENERIC_ENTRY +/* + * CONFIG_GENERIC_ENTRY relies on compiler emitted mem*() calls to not be + * instrumented. KASAN enabled toolchains should emit __asan_mem*() functions + * for the sites they want to instrument. + */ #undef memset void *memset(void *addr, int c, size_t len) { @@ -68,6 +74,38 @@ void *memcpy(void *dest, const void *src return __memcpy(dest, src, len); } +#endif + +void *__asan_memset(void *addr, int c, size_t len) +{ + if (!kasan_check_range((unsigned long)addr, len, true, _RET_IP_)) + return NULL; + + return __memset(addr, c, len); +} +EXPORT_SYMBOL(__asan_memset); + +#ifdef __HAVE_ARCH_MEMMOVE +void *__asan_memmove(void *dest, const void *src, size_t len) +{ + if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) || + !kasan_check_range((unsigned long)dest, len, true, _RET_IP_)) + return NULL; + + return __memmove(dest, src, len); +} +EXPORT_SYMBOL(__asan_memmove); +#endif + +void *__asan_memcpy(void *dest, const void *src, size_t len) +{ + if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) || + !kasan_check_range((unsigned long)dest, len, true, _RET_IP_)) + return NULL; + + return __memcpy(dest, src, len); +} +EXPORT_SYMBOL(__asan_memcpy); void kasan_poison(const void *addr, size_t size, u8 value, bool init) { --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -956,6 +956,9 @@ static const char *uaccess_safe_builtin[ "__asan_store16_noabort", "__kasan_check_read", "__kasan_check_write", + "__asan_memset", + "__asan_memmove", + "__asan_memcpy", /* KASAN in-line */ "__asan_report_load_n_noabort", "__asan_report_load1_noabort",