lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 29 May 2019 07:29:01 -0700 From: hpa@...or.com To: Marco Elver <elver@...gle.com>, peterz@...radead.org, aryabinin@...tuozzo.com, dvyukov@...gle.com, glider@...gle.com, andreyknvl@...gle.com, mark.rutland@....com CC: corbet@....net, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org, arnd@...db.de, jpoimboe@...hat.com, linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org, kasan-dev@...glegroups.com Subject: Re: [PATCH 2/3] x86: Move CPU feature test out of uaccess region On May 29, 2019 7:15:00 AM PDT, Marco Elver <elver@...gle.com> wrote: >This patch is a pre-requisite for enabling KASAN bitops >instrumentation: >moves boot_cpu_has feature test out of the uaccess region, as >boot_cpu_has uses test_bit. With instrumentation, the KASAN check would >otherwise be flagged by objtool. > >This approach is preferred over adding the explicit kasan_check_* >functions to the uaccess whitelist of objtool, as the case here appears >to be the only one. > >Signed-off-by: Marco Elver <elver@...gle.com> >--- >v1: >* This patch replaces patch: 'tools/objtool: add kasan_check_* to > uaccess whitelist' >--- > arch/x86/ia32/ia32_signal.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > >diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c >index 629d1ee05599..12264e3c9c43 100644 >--- a/arch/x86/ia32/ia32_signal.c >+++ b/arch/x86/ia32/ia32_signal.c >@@ -333,6 +333,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal >*ksig, > void __user *restorer; > int err = 0; > void __user *fpstate = NULL; >+ bool has_xsave; > > /* __copy_to_user optimizes that into a single 8 byte store */ > static const struct { >@@ -352,13 +353,19 @@ int ia32_setup_rt_frame(int sig, struct ksignal >*ksig, > if (!access_ok(frame, sizeof(*frame))) > return -EFAULT; > >+ /* >+ * Move non-uaccess accesses out of uaccess region if not strictly >+ * required; this also helps avoid objtool flagging these accesses >with >+ * instrumentation enabled. >+ */ >+ has_xsave = boot_cpu_has(X86_FEATURE_XSAVE); > put_user_try { > put_user_ex(sig, &frame->sig); > put_user_ex(ptr_to_compat(&frame->info), &frame->pinfo); > put_user_ex(ptr_to_compat(&frame->uc), &frame->puc); > > /* Create the ucontext. */ >- if (boot_cpu_has(X86_FEATURE_XSAVE)) >+ if (has_xsave) > put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); > else > put_user_ex(0, &frame->uc.uc_flags); This was meant to use static_cpu_has(). Why did that get dropped? -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
Powered by blists - more mailing lists