From patchwork Wed Apr 12 18:32:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 82623 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp534679vqo; Wed, 12 Apr 2023 11:46:06 -0700 (PDT) X-Google-Smtp-Source: AKy350Zwf3/eXyXDOrxcWoSEqTZYICEY178qR9FW59lYyBQCmy++4mvhj0NX8GHQ7yaGkTNBai57 X-Received: by 2002:a05:6a20:c21f:b0:eb:9e31:fba0 with SMTP id bt31-20020a056a20c21f00b000eb9e31fba0mr3502364pzb.20.1681325166100; Wed, 12 Apr 2023 11:46:06 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1681325166; cv=none; d=google.com; s=arc-20160816; b=EBekJ5nMdX8vPdKEfZq2Ub065AvZcmTjW1iOAJitZSX753DsQct2KhlPSK4cNlldrG /yFPDG+3YLA90f/LP4s9xbSQCs3HYpIOrqie91ZYg51mGEejw6Fl4aQBrqVdhFrYy3h4 5ndX4uLVFa1Uo/6PFkhavB+Z/kDSluEge8s7HCP4aaK4lh3hMeyNiwp5PfCG8rJGZl0d qd9g4ort1nKbOmrTm7aJ6lOwBQ/5XwDS8ILhTqM3ucBBJjJITAzkq4q7AsAB54GsHBCH J6VGWAPxBXKLKMTr7/T7ALn8dMRRjjJvqlJvRrmUToA8CNxP3qN6aSga6Lye+tX7rDla 2GJA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=fu4wMIjRXEHdvIAwW21s7RwYEcTiORI4Tua6uqoa9YY=; b=Sy/zK0zvyyVzI5Zjw0AyVMigUCnGjCE8R3HJpewRCHol9GDKmHHppKbfIa6Cnapsjt frBKYJ0f3CLOrxednhdDvPxhOBREhdCX+BKvpAuE67AtBPIkR3RLo9Mr4CIN5z0Lkpcv eKFabqFkaVCAISMllwovjV0OCEPujfS+5oqZKnqTIXR44DBzbDsKjB7AdQXjUTeeJxAA L+v9rYF3hr8XObiiA8+TJWHnwcdWXIiO/vWmRgdbkf7t1NUIoYk797MRCPl9T8v4tLvd BE24pTIH79769q48szYCjFNh5eKtEA7kbB3niyQEHGa6gT0Q8qxfwHb/jKyBb7ZQrrYp rqNA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=gHtYL1L3; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. 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This was fixed in gcc-11. Now that the function attribute is available, let's start using it. Callers of boot_init_stack_canary need to use this function attribute unless they're compiled with -fno-stack-protector, otherwise the canary stored in the stack slot of the caller will differ upon the call to boot_init_stack_canary. This will lead to a call to __stack_chk_fail then panic. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94722 Link: https://lore.kernel.org/all/20200316130414.GC12561@hirez.programming.kicks-ass.net/ Signed-off-by: Nick Desaulniers Acked-by: Miguel Ojeda Tested-by: Nathan Chancellor Acked-by: Michael Ellerman (powerpc) --- arch/powerpc/kernel/smp.c | 1 + include/linux/compiler_attributes.h | 12 ++++++++++++ init/main.c | 3 ++- 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 6b90f10a6c81..7d4c12b1abb7 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -1603,6 +1603,7 @@ static void add_cpu_to_masks(int cpu) } /* Activate a secondary processor. */ +__no_stack_protector void start_secondary(void *unused) { unsigned int cpu = raw_smp_processor_id(); diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index e659cb6fded3..84864767a56a 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -255,6 +255,18 @@ */ #define __noreturn __attribute__((__noreturn__)) +/* + * Optional: only supported since GCC >= 11.1, clang >= 7.0. + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-no_005fstack_005fprotector-function-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#no-stack-protector-safebuffers + */ +#if __has_attribute(__no_stack_protector__) +# define __no_stack_protector __attribute__((__no_stack_protector__)) +#else +# define __no_stack_protector +#endif + /* * Optional: not supported by gcc. * diff --git a/init/main.c b/init/main.c index bb87b789c543..213baf7b8cb1 100644 --- a/init/main.c +++ b/init/main.c @@ -941,7 +941,8 @@ static void __init print_unknown_bootoptions(void) memblock_free(unknown_options, len); } -asmlinkage __visible void __init __no_sanitize_address start_kernel(void) +asmlinkage __visible __init __no_sanitize_address __no_stack_protector +void start_kernel(void) { char *command_line; char *after_dashes; From patchwork Wed Apr 12 18:32:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 82624 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp535251vqo; Wed, 12 Apr 2023 11:47:19 -0700 (PDT) X-Google-Smtp-Source: AKy350ZoU1hGOc1u17n8yY2gcCk2ekiHCxV+tqvCgzRcQkRzaNXj1lORqOCOm+zDyBUgB/mF7214 X-Received: by 2002:a05:6a20:c414:b0:eb:a859:e870 with SMTP id en20-20020a056a20c41400b000eba859e870mr418716pzb.20.1681325238769; Wed, 12 Apr 2023 11:47:18 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1681325238; cv=none; d=google.com; s=arc-20160816; b=T1sNkp6PaFpyH1xWI5G/NdTv8wfmD7mdIZiOTsb8/YktguHc3j8y3u1WWj5gPRPbmF ML2S48/P+nhcz6a6b4nH9XLNFSnQZ+d6ymQ4Qo9zgVAUqOaisXPW06GcUnblsbTcVI66 TXicrVql02KrbvpcP+gLDOkEl8df6o1v5F46mwS7itp/oUchGM2ilU5plPPCjznc3/Xx Y7hPcrQ4xGL7lfcceUf/S/trkmW1u4Ikjre92S6sHJS3M9AlMboH8rJ06f+hxvsPI00J V7Yx+6CewXK2wBN/h+MRYr9iUSuAtS/ZxjUqRUV35BrdBcW4/oyV/crIKU26bVTQhaah LC9Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=B8Xgas6M12Xeefyhuwpcw2QRuGFdbq5fzUL3tcrdyh4=; b=H1ljlnRGOnf7egknU4NMsBJ9QSfXkA26jpHkza34k/Klf0nkpNYz/oeLs3ncaGc3g9 NzkN8c7fx1NRwrCYGIfBryi2Prf00Mf/ZQMf8V24jnL4K0DymnCGJqrlwsUlhkSGsF+H E4KaWrNBqLHQL7yBIEdOoljqFmaha8V8V0DKaICcAGasN2DEO0jxcZpnvC2bqajxpOOc M3UvvIi7xJqYbaKK559iA7Qo4b6jxcTVz7auLFKWAzhl7Bx5gup83u/RYmnDm+Y9Coln Ca0p31uONvwnnghfzgLMecHc5bsEJ9788PB42s890HJ9+I5dqkLpvYwAehcCqxcWHPPj MhLg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=iXUKQ4qf; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. 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Now that we have no_stack_protector function attribute (gcc-11+, clang-7+) and use it on start_kernel, remove the call to prevent_tail_call_optimization such that we may one day remove it outright. Signed-off-by: Nick Desaulniers Reviewed-by: Nathan Chancellor --- init/main.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/init/main.c b/init/main.c index 213baf7b8cb1..c8503d02dfa6 100644 --- a/init/main.c +++ b/init/main.c @@ -1152,7 +1152,12 @@ void start_kernel(void) /* Do the rest non-__init'ed, we're now alive */ arch_call_rest_init(); + /* Avoid stack canaries in callers of boot_init_stack_canary for gcc-10 + * and older. + */ +#if !__has_attribute(__no_stack_protector__) prevent_tail_call_optimization(); +#endif } /* Call all constructor functions linked into the kernel. */