From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Garnier Date: Wed, 4 Oct 2017 14:19:49 -0700 Message-Id: <20171004212003.28296-14-thgarnie@google.com> In-Reply-To: <20171004212003.28296-1-thgarnie@google.com> References: <20171004212003.28296-1-thgarnie@google.com> Subject: [kernel-hardening] [RFC v3 13/27] x86/boot/64: Use _text in a global for PIE support To: Herbert Xu , "David S . Miller" , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , Josh Poimboeuf , Thomas Garnier , Arnd Bergmann , Kees Cook , Matthias Kaehlcke , Tom Lendacky , Andy Lutomirski , "Kirill A . Shutemov" , Borislav Petkov , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Juergen Gross , Chris Wright , Alok Kataria , Rusty Russell , Tejun Heo , Christoph Lameter , Boris Ostrovsky , Alexey Dobriyan , Andrew Morton , Paul Gortmaker , Chris Metcalf , "Paul E . McKenney" , Nicolas Pitre , Borislav Petkov , "Luis R . Rodriguez" , Greg Kroah-Hartman , Christopher Li , Steven Rostedt , Jason Baron , Dou Liyang , "Rafael J . Wysocki" , Mika Westerberg , Lukas Wunner , Masahiro Yamada , Alexei Starovoitov , Daniel Borkmann , Markus Trippelsdorf , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Joerg Roedel , Rik van Riel , David Howells , Ard Biesheuvel , Waiman Long , Kyle Huey , Andrey Ryabinin , Jonathan Corbet , Matthew Wilcox , Michal Hocko , Peter Foley , Paul Bolle , Jiri Kosina , Rob Landley , "H . J . Lu" , Baoquan He , =?UTF-8?q?Jan=20H=20=2E=20Sch=C3=B6nherr?= , Daniel Micay Cc: x86@kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, virtualization@lists.linux-foundation.org, xen-devel@lists.xenproject.org, linux-arch@vger.kernel.org, linux-sparse@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com List-ID: By default PIE generated code create only relative references so _text points to the temporary virtual address. Instead use a global variable so the relocation is done as expected. Position Independent Executable (PIE) support will allow to extended the KASLR randomization range below the -2G memory limit. Signed-off-by: Thomas Garnier --- arch/x86/kernel/head64.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index bab4fa579450..675f1dba3b21 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -45,8 +45,14 @@ static void __head *fixup_pointer(void *ptr, unsigned long physaddr) return ptr - (void *)_text + (void *)physaddr; } -unsigned long __head __startup_64(unsigned long physaddr, - struct boot_params *bp) +/* + * Use a global variable to properly calculate _text delta on PIE. By default + * a PIE binary do a RIP relative difference instead of the relocated address. + */ +unsigned long _text_offset = (unsigned long)(_text - __START_KERNEL_map); + +unsigned long __head notrace __startup_64(unsigned long physaddr, + struct boot_params *bp) { unsigned long load_delta, *p; unsigned long pgtable_flags; @@ -65,7 +71,7 @@ unsigned long __head __startup_64(unsigned long physaddr, * Compute the delta between the address I am compiled to run at * and the address I am actually running at. */ - load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map); + load_delta = physaddr - _text_offset; /* Is the address not 2M aligned? */ if (load_delta & ~PMD_PAGE_MASK) -- 2.14.2.920.gcf0c67979c-goog From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Garnier Subject: [RFC v3 13/27] x86/boot/64: Use _text in a global for PIE support Date: Wed, 4 Oct 2017 14:19:49 -0700 Message-ID: <20171004212003.28296-14-thgarnie@google.com> References: <20171004212003.28296-1-thgarnie@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20171004212003.28296-1-thgarnie@google.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" To: Herbert Xu , "David S . Miller" , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , Josh Poimboeuf , Thomas Garnier , Arnd Bergmann , Kees Cook , Matthias Kaehlcke , Tom Lendacky , Andy Lutomirski , "Kirill A . Shutemov" , Borislav Petkov , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Juergen Gross , Chris Wright , Alok Kataria , Rusty Russell , Tejun Heo , Christoph Lameter Bor Cc: linux-arch@vger.kernel.org, kvm@vger.kernel.org, linux-pm@vger.kernel.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-sparse@vger.kernel.org, linux-crypto@vger.kernel.org, kernel-hardening@lists.openwall.com, xen-devel@lists.xenproject.org List-Id: linux-arch.vger.kernel.org QnkgZGVmYXVsdCBQSUUgZ2VuZXJhdGVkIGNvZGUgY3JlYXRlIG9ubHkgcmVsYXRpdmUgcmVmZXJl bmNlcyBzbyBfdGV4dApwb2ludHMgdG8gdGhlIHRlbXBvcmFyeSB2aXJ0dWFsIGFkZHJlc3MuIElu c3RlYWQgdXNlIGEgZ2xvYmFsIHZhcmlhYmxlCnNvIHRoZSByZWxvY2F0aW9uIGlzIGRvbmUgYXMg ZXhwZWN0ZWQuCgpQb3NpdGlvbiBJbmRlcGVuZGVudCBFeGVjdXRhYmxlIChQSUUpIHN1cHBvcnQg d2lsbCBhbGxvdyB0byBleHRlbmRlZCB0aGUKS0FTTFIgcmFuZG9taXphdGlvbiByYW5nZSBiZWxv dyB0aGUgLTJHIG1lbW9yeSBsaW1pdC4KClNpZ25lZC1vZmYtYnk6IFRob21hcyBHYXJuaWVyIDx0 aGdhcm5pZUBnb29nbGUuY29tPgotLS0KIGFyY2gveDg2L2tlcm5lbC9oZWFkNjQuYyB8IDEyICsr KysrKysrKy0tLQogMSBmaWxlIGNoYW5nZWQsIDkgaW5zZXJ0aW9ucygrKSwgMyBkZWxldGlvbnMo LSkKCmRpZmYgLS1naXQgYS9hcmNoL3g4Ni9rZXJuZWwvaGVhZDY0LmMgYi9hcmNoL3g4Ni9rZXJu ZWwvaGVhZDY0LmMKaW5kZXggYmFiNGZhNTc5NDUwLi42NzVmMWRiYTNiMjEgMTAwNjQ0Ci0tLSBh L2FyY2gveDg2L2tlcm5lbC9oZWFkNjQuYworKysgYi9hcmNoL3g4Ni9rZXJuZWwvaGVhZDY0LmMK QEAgLTQ1LDggKzQ1LDE0IEBAIHN0YXRpYyB2b2lkIF9faGVhZCAqZml4dXBfcG9pbnRlcih2b2lk ICpwdHIsIHVuc2lnbmVkIGxvbmcgcGh5c2FkZHIpCiAJcmV0dXJuIHB0ciAtICh2b2lkICopX3Rl eHQgKyAodm9pZCAqKXBoeXNhZGRyOwogfQogCi11bnNpZ25lZCBsb25nIF9faGVhZCBfX3N0YXJ0 dXBfNjQodW5zaWduZWQgbG9uZyBwaHlzYWRkciwKLQkJCQkgIHN0cnVjdCBib290X3BhcmFtcyAq YnApCisvKgorICogVXNlIGEgZ2xvYmFsIHZhcmlhYmxlIHRvIHByb3Blcmx5IGNhbGN1bGF0ZSBf dGV4dCBkZWx0YSBvbiBQSUUuIEJ5IGRlZmF1bHQKKyAqIGEgUElFIGJpbmFyeSBkbyBhIFJJUCBy ZWxhdGl2ZSBkaWZmZXJlbmNlIGluc3RlYWQgb2YgdGhlIHJlbG9jYXRlZCBhZGRyZXNzLgorICov Cit1bnNpZ25lZCBsb25nIF90ZXh0X29mZnNldCA9ICh1bnNpZ25lZCBsb25nKShfdGV4dCAtIF9f U1RBUlRfS0VSTkVMX21hcCk7CisKK3Vuc2lnbmVkIGxvbmcgX19oZWFkIG5vdHJhY2UgX19zdGFy dHVwXzY0KHVuc2lnbmVkIGxvbmcgcGh5c2FkZHIsCisJCQkJCSAgc3RydWN0IGJvb3RfcGFyYW1z ICpicCkKIHsKIAl1bnNpZ25lZCBsb25nIGxvYWRfZGVsdGEsICpwOwogCXVuc2lnbmVkIGxvbmcg cGd0YWJsZV9mbGFnczsKQEAgLTY1LDcgKzcxLDcgQEAgdW5zaWduZWQgbG9uZyBfX2hlYWQgX19z dGFydHVwXzY0KHVuc2lnbmVkIGxvbmcgcGh5c2FkZHIsCiAJICogQ29tcHV0ZSB0aGUgZGVsdGEg YmV0d2VlbiB0aGUgYWRkcmVzcyBJIGFtIGNvbXBpbGVkIHRvIHJ1biBhdAogCSAqIGFuZCB0aGUg YWRkcmVzcyBJIGFtIGFjdHVhbGx5IHJ1bm5pbmcgYXQuCiAJICovCi0JbG9hZF9kZWx0YSA9IHBo eXNhZGRyIC0gKHVuc2lnbmVkIGxvbmcpKF90ZXh0IC0gX19TVEFSVF9LRVJORUxfbWFwKTsKKwls b2FkX2RlbHRhID0gcGh5c2FkZHIgLSBfdGV4dF9vZmZzZXQ7CiAKIAkvKiBJcyB0aGUgYWRkcmVz cyBub3QgMk0gYWxpZ25lZD8gKi8KIAlpZiAobG9hZF9kZWx0YSAmIH5QTURfUEFHRV9NQVNLKQot LSAKMi4xNC4yLjkyMC5nY2YwYzY3OTc5Yy1nb29nCgoKX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX18KWGVuLWRldmVsIG1haWxpbmcgbGlzdApYZW4tZGV2ZWxA bGlzdHMueGVuLm9yZwpodHRwczovL2xpc3RzLnhlbi5vcmcveGVuLWRldmVsCg== From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Garnier Subject: [RFC v3 13/27] x86/boot/64: Use _text in a global for PIE support Date: Wed, 4 Oct 2017 14:19:49 -0700 Message-ID: <20171004212003.28296-14-thgarnie@google.com> References: <20171004212003.28296-1-thgarnie@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Cc: linux-arch@vger.kernel.org, kvm@vger.kernel.org, linux-pm@vger.kernel.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-sparse@vger.kernel.org, linux-crypto@vger.kernel.org, kernel-hardening@lists.openwall.com, xen-devel@lists.xenproject.org To: Herbert Xu , "David S . Miller" , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , Josh Poimboeuf , Thomas Garnier , Arnd Bergmann , Kees Cook , Matthias Kaehlcke , Tom Lendacky , Andy Lutomirski , "Kirill A . Shutemov" , Borislav Petkov , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Juergen Gross , Chris Wright , Alok Kataria , Rusty Russell , Tejun Heo , Christoph Lameter , Bor Return-path: In-Reply-To: <20171004212003.28296-1-thgarnie@google.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" List-Id: linux-crypto.vger.kernel.org QnkgZGVmYXVsdCBQSUUgZ2VuZXJhdGVkIGNvZGUgY3JlYXRlIG9ubHkgcmVsYXRpdmUgcmVmZXJl bmNlcyBzbyBfdGV4dApwb2ludHMgdG8gdGhlIHRlbXBvcmFyeSB2aXJ0dWFsIGFkZHJlc3MuIElu c3RlYWQgdXNlIGEgZ2xvYmFsIHZhcmlhYmxlCnNvIHRoZSByZWxvY2F0aW9uIGlzIGRvbmUgYXMg ZXhwZWN0ZWQuCgpQb3NpdGlvbiBJbmRlcGVuZGVudCBFeGVjdXRhYmxlIChQSUUpIHN1cHBvcnQg d2lsbCBhbGxvdyB0byBleHRlbmRlZCB0aGUKS0FTTFIgcmFuZG9taXphdGlvbiByYW5nZSBiZWxv dyB0aGUgLTJHIG1lbW9yeSBsaW1pdC4KClNpZ25lZC1vZmYtYnk6IFRob21hcyBHYXJuaWVyIDx0 aGdhcm5pZUBnb29nbGUuY29tPgotLS0KIGFyY2gveDg2L2tlcm5lbC9oZWFkNjQuYyB8IDEyICsr KysrKysrKy0tLQogMSBmaWxlIGNoYW5nZWQsIDkgaW5zZXJ0aW9ucygrKSwgMyBkZWxldGlvbnMo LSkKCmRpZmYgLS1naXQgYS9hcmNoL3g4Ni9rZXJuZWwvaGVhZDY0LmMgYi9hcmNoL3g4Ni9rZXJu ZWwvaGVhZDY0LmMKaW5kZXggYmFiNGZhNTc5NDUwLi42NzVmMWRiYTNiMjEgMTAwNjQ0Ci0tLSBh L2FyY2gveDg2L2tlcm5lbC9oZWFkNjQuYworKysgYi9hcmNoL3g4Ni9rZXJuZWwvaGVhZDY0LmMK QEAgLTQ1LDggKzQ1LDE0IEBAIHN0YXRpYyB2b2lkIF9faGVhZCAqZml4dXBfcG9pbnRlcih2b2lk ICpwdHIsIHVuc2lnbmVkIGxvbmcgcGh5c2FkZHIpCiAJcmV0dXJuIHB0ciAtICh2b2lkICopX3Rl eHQgKyAodm9pZCAqKXBoeXNhZGRyOwogfQogCi11bnNpZ25lZCBsb25nIF9faGVhZCBfX3N0YXJ0 dXBfNjQodW5zaWduZWQgbG9uZyBwaHlzYWRkciwKLQkJCQkgIHN0cnVjdCBib290X3BhcmFtcyAq YnApCisvKgorICogVXNlIGEgZ2xvYmFsIHZhcmlhYmxlIHRvIHByb3Blcmx5IGNhbGN1bGF0ZSBf dGV4dCBkZWx0YSBvbiBQSUUuIEJ5IGRlZmF1bHQKKyAqIGEgUElFIGJpbmFyeSBkbyBhIFJJUCBy ZWxhdGl2ZSBkaWZmZXJlbmNlIGluc3RlYWQgb2YgdGhlIHJlbG9jYXRlZCBhZGRyZXNzLgorICov Cit1bnNpZ25lZCBsb25nIF90ZXh0X29mZnNldCA9ICh1bnNpZ25lZCBsb25nKShfdGV4dCAtIF9f U1RBUlRfS0VSTkVMX21hcCk7CisKK3Vuc2lnbmVkIGxvbmcgX19oZWFkIG5vdHJhY2UgX19zdGFy dHVwXzY0KHVuc2lnbmVkIGxvbmcgcGh5c2FkZHIsCisJCQkJCSAgc3RydWN0IGJvb3RfcGFyYW1z ICpicCkKIHsKIAl1bnNpZ25lZCBsb25nIGxvYWRfZGVsdGEsICpwOwogCXVuc2lnbmVkIGxvbmcg cGd0YWJsZV9mbGFnczsKQEAgLTY1LDcgKzcxLDcgQEAgdW5zaWduZWQgbG9uZyBfX2hlYWQgX19z dGFydHVwXzY0KHVuc2lnbmVkIGxvbmcgcGh5c2FkZHIsCiAJICogQ29tcHV0ZSB0aGUgZGVsdGEg YmV0d2VlbiB0aGUgYWRkcmVzcyBJIGFtIGNvbXBpbGVkIHRvIHJ1biBhdAogCSAqIGFuZCB0aGUg YWRkcmVzcyBJIGFtIGFjdHVhbGx5IHJ1bm5pbmcgYXQuCiAJICovCi0JbG9hZF9kZWx0YSA9IHBo eXNhZGRyIC0gKHVuc2lnbmVkIGxvbmcpKF90ZXh0IC0gX19TVEFSVF9LRVJORUxfbWFwKTsKKwls b2FkX2RlbHRhID0gcGh5c2FkZHIgLSBfdGV4dF9vZmZzZXQ7CiAKIAkvKiBJcyB0aGUgYWRkcmVz cyBub3QgMk0gYWxpZ25lZD8gKi8KIAlpZiAobG9hZF9kZWx0YSAmIH5QTURfUEFHRV9NQVNLKQot LSAKMi4xNC4yLjkyMC5nY2YwYzY3OTc5Yy1nb29nCgoKX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX18KWGVuLWRldmVsIG1haWxpbmcgbGlzdApYZW4tZGV2ZWxA bGlzdHMueGVuLm9yZwpodHRwczovL2xpc3RzLnhlbi5vcmcveGVuLWRldmVsCg==