Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965436Ab3FTPOK (ORCPT ); Thu, 20 Jun 2013 11:14:10 -0400 Received: from mail-ea0-f179.google.com ([209.85.215.179]:45085 "EHLO mail-ea0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965153Ab3FTPOI (ORCPT ); Thu, 20 Jun 2013 11:14:08 -0400 From: Ghennadi Procopciuc To: akpm@linux-foundation.org, js1304@gmail.com, rientjes@google.com, minchan@kernel.org, kosaki.motohiro@jp.fujitsu.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Ghennadi Procopciuc , Daniel Baluta Subject: [PATCH] mm: fix overflow in alloc_vmap_area Date: Thu, 20 Jun 2013 18:12:30 +0300 Message-Id: <1371741150-10861-1-git-send-email-unix140@gmail.com> X-Mailer: git-send-email 1.8.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4461 Lines: 112 Inserting the following kernel module: static int simple_test_init(void) { size_t i, j; void *address; for (i = 0 * MB; i< 60 * MB; i += 1 * MB) { for (j = i; j< i + 1 * MB; j += KB) { address = vmalloc(j); vfree(address); } } return 0; } triggers BUG at mm/vmalloc.c:310 on a x86 machine: [ 95.218283] Kernel BUG at c1126cdb [verbose debug info unavailable] [ 95.218306] invalid opcode: 0000 [#1] SMP [ 95.218324] Modules linked in: lkma_test(OF+) [ 95.218559] Pid: 2419, comm: insmod Tainted: GF O 3.9.0+ #57 Hewlett-Packard HP Compaq 8200 Elite CMT PC/1494 [ 95.218597] EIP: 0060:[] EFLAGS: 00010207 CPU: 3 [ 95.218617] EIP is at __insert_vmap_area+0xfb/0x100 [ 95.218635] EAX: f85dc000 EBX: ef05cac0 ECX: f7be08c4 EDX: 00000007 [ 95.218657] ESI: f2ed044c EDI: c1a220b8 EBP: f027bd34 ESP: f027bd14 [ 95.218680] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 95.218699] CR0: 80050033 CR2: b5995118 CR3: 30364000 CR4: 000407f0 [ 95.218721] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 95.218743] DR6: ffff0ff0 DR7: 00000400 [ 95.218758] Process insmod (pid: 2419, ti=f027a000 task=efe64010 task.ti=f027a000) [ 95.218784] Stack: [ 95.218792] c177b964 fecfb000 f85e2000 00000000 f85dc000 ffbfe000 f02da1c0 0007f000 [ 95.218829] f027bd7c c112802d c177b9b0 fecfb000 01305000 ffbfe000 00000001 ef05cac0 [ 95.218866] 00000000 00000000 f83fe000 01304fff f83fe000 ffffffff 01305000 ef05c500 [ 95.218903] Call Trace: [ 95.218915] [] ? 0xf85e1fff [ 95.218930] [] ? 0xf85dbfff [ 95.218945] [] alloc_vmap_area.isra.16+0x1bd/0x2f0 [ 95.218967] [] __get_vm_area_node.isra.17+0x8f/0x130 [ 95.218988] [] __vmalloc_node_range+0x57/0x200 [ 95.219009] [] ? lkma_test_init+0x45/0x70 [lkma_test] [ 95.219031] [] __vmalloc_node+0x62/0x70 [ 95.219049] [] ? lkma_test_init+0x45/0x70 [lkma_test] [ 95.219071] [] vmalloc+0x38/0x40 [ 95.219087] [] ? lkma_test_init+0x45/0x70 [lkma_test] [ 95.219109] [] lkma_test_init+0x45/0x70 [lkma_test] [ 95.219131] [] ? kzalloc+0x10/0x10 [lkma_test] [ 95.219151] [] do_one_initcall+0x112/0x160 [ 95.219171] [] ? set_section_ro_nx+0x54/0x59 [ 95.219190] [] load_module+0x1d79/0x2660 [ 95.219209] [] ? create_object+0x19d/0x280 [ 95.219230] [] sys_init_module+0x78/0xb0 [ 95.219250] [] sysenter_do_call+0x12/0x22 [ 95.219268] Code: 39 03 73 0c 8b 3f 89 f0 83 c7 08 e9 3d ff ff ff 8b 46 f4 39 43 04 76 13 8b 3f 89 f0 83 c7 04 e9 29 ff ff ff e8 fb 1b 4a 00 eb ab<0f> 0b 8d 76 00 55 89 e5 56 53 66 66 66 66 90 83 60 0c df 89 c6 [ 95.219415] EIP: [] __insert_vmap_area+0xfb/0x100 SS:ESP 0068:f027bd14 [ 95.228313] ---[ end trace e0a1efb2acb97c98 ]--- A printk placed in __insert_vmap_area will show: [ 95.218256] va->va_start=0xfecfb000 tmp_va->va_end=0xf85e2000 va->va_end=0 tmp_va->va_start=0xf85dc000 and another one, before sum operation in alloc_vmap_area: [ 95.218204] addr = 0xfecfb000 size = 19943424 vend = 0xffbfe000 If after addition the result is smaller than one of the arguments, then an overflow occurred. In our case there is an obvious overflow. Signed-off-by: Ghennadi Procopciuc Cc: Daniel Baluta --- Don't know if this is the right solution, but the bug happens for me in 3.10-rc6 and 3.9. --- mm/vmalloc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 0f751f2..6ea525c 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -421,12 +421,13 @@ nocache: } found: - if (addr + size > vend) + va->va_end = addr + size; + if (va->va_end < addr || va->va_end < size || va->va_end > vend) goto overflow; va->va_start = addr; - va->va_end = addr + size; va->flags = 0; + __insert_vmap_area(va); free_vmap_cache = &va->rb_node; spin_unlock(&vmap_area_lock); -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/