From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752825AbdCBNtR (ORCPT ); Thu, 2 Mar 2017 08:49:17 -0500 Received: from mail-wr0-f174.google.com ([209.85.128.174]:36437 "EHLO mail-wr0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752618AbdCBNtG (ORCPT ); Thu, 2 Mar 2017 08:49:06 -0500 From: Andrey Konovalov To: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Andrey Konovalov Subject: [PATCH v2 0/9] kasan: improve error reports Date: Thu, 2 Mar 2017 14:48:42 +0100 Message-Id: <20170302134851.101218-1-andreyknvl@google.com> X-Mailer: git-send-email 2.12.0.rc1.440.g5b76565f74-goog Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patchset improves KASAN reports by making them easier to read and a little more detailed. Also improves mm/kasan/report.c readability. Effectively changes a use-after-free report to: ================================================================== BUG: KASAN: use-after-free in kmalloc_uaf+0xaa/0xb6 [test_kasan] Write of size 1 at addr ffff88006aa59da8 by task insmod/3951 CPU: 1 PID: 3951 Comm: insmod Tainted: G B 4.10.0+ #84 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x292/0x398 print_address_description+0x73/0x280 kasan_report.part.2+0x207/0x2f0 __asan_report_store1_noabort+0x2c/0x30 kmalloc_uaf+0xaa/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x7f22cfd0b9da RSP: 002b:00007ffe69118a78 EFLAGS: 00000206 ORIG_RAX: 00000000000000af RAX: ffffffffffffffda RBX: 0000555671242090 RCX: 00007f22cfd0b9da RDX: 00007f22cffcaf88 RSI: 000000000004df7e RDI: 00007f22d0399000 RBP: 00007f22cffcaf88 R08: 0000000000000003 R09: 0000000000000000 R10: 00007f22cfd07d0a R11: 0000000000000206 R12: 0000555671243190 R13: 000000000001fe81 R14: 0000000000000000 R15: 0000000000000004 Allocated by task 3951: save_stack_trace+0x16/0x20 save_stack+0x43/0xd0 kasan_kmalloc+0xad/0xe0 kmem_cache_alloc_trace+0x82/0x270 kmalloc_uaf+0x56/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 Freed by task 3951: save_stack_trace+0x16/0x20 save_stack+0x43/0xd0 kasan_slab_free+0x72/0xc0 kfree+0xe8/0x2b0 kmalloc_uaf+0x85/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc The buggy address belongs to the object at ffff88006aa59da0 which belongs to the cache kmalloc-16 of size 16 The buggy address is located 8 bytes inside of 16-byte region [ffff88006aa59da0, ffff88006aa59db0) The buggy address belongs to the page: page:ffffea0001aa9640 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x100000000000100(slab) raw: 0100000000000100 0000000000000000 0000000000000000 0000000180800080 raw: ffffea0001abe380 0000000700000007 ffff88006c401b40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88006aa59c80: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc ffff88006aa59d00: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc >ffff88006aa59d80: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ^ ffff88006aa59e00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ffff88006aa59e80: fb fb fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc ================================================================== from: ================================================================== BUG: KASAN: use-after-free in kmalloc_uaf+0xaa/0xb6 [test_kasan] at addr ffff88006c4dcb28 Write of size 1 by task insmod/3984 CPU: 1 PID: 3984 Comm: insmod Tainted: G B 4.10.0+ #83 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x292/0x398 kasan_object_err+0x1c/0x70 kasan_report.part.1+0x20e/0x4e0 __asan_report_store1_noabort+0x2c/0x30 kmalloc_uaf+0xaa/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x7feca0f779da RSP: 002b:00007ffdfeae5218 EFLAGS: 00000206 ORIG_RAX: 00000000000000af RAX: ffffffffffffffda RBX: 000055a064c13090 RCX: 00007feca0f779da RDX: 00007feca1236f88 RSI: 000000000004df7e RDI: 00007feca1605000 RBP: 00007feca1236f88 R08: 0000000000000003 R09: 0000000000000000 R10: 00007feca0f73d0a R11: 0000000000000206 R12: 000055a064c14190 R13: 000000000001fe81 R14: 0000000000000000 R15: 0000000000000004 Object at ffff88006c4dcb20, in cache kmalloc-16 size: 16 Allocated: PID = 3984 save_stack_trace+0x16/0x20 save_stack+0x43/0xd0 kasan_kmalloc+0xad/0xe0 kmem_cache_alloc_trace+0x82/0x270 kmalloc_uaf+0x56/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 Freed: PID = 3984 save_stack_trace+0x16/0x20 save_stack+0x43/0xd0 kasan_slab_free+0x73/0xc0 kfree+0xe8/0x2b0 kmalloc_uaf+0x85/0xb6 [test_kasan] kmalloc_tests_init+0x4f/0xa48 [test_kasan] do_one_initcall+0xf3/0x390 do_init_module+0x215/0x5d0 load_module+0x54de/0x82b0 SYSC_init_module+0x3be/0x430 SyS_init_module+0x9/0x10 entry_SYSCALL_64_fastpath+0x1f/0xc2 Memory state around the buggy address: ffff88006c4dca00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ffff88006c4dca80: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc >ffff88006c4dcb00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ^ ffff88006c4dcb80: fb fb fc fc 00 00 fc fc fb fb fc fc fb fb fc fc ffff88006c4dcc00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc ================================================================== Changes in v2: - split patch in multiple smaller ones - improve double-free reports Andrey Konovalov (9): kasan: introduce helper functions for determining bug type kasan: unify report headers kasan: change allocation and freeing stack traces headers kasan: simplify address description logic kasan: change report header kasan: improve slab object description kasan: print page description after stacks kasan: improve double-free report format kasan: separate report parts by empty lines mm/kasan/kasan.c | 3 +- mm/kasan/kasan.h | 2 +- mm/kasan/report.c | 187 ++++++++++++++++++++++++++++++++++++------------------ 3 files changed, 127 insertions(+), 65 deletions(-) -- 2.12.0.rc1.440.g5b76565f74-goog