On Wed, Mar 20, 2019 at 11:57 AM Eric Biggers <ebigg...@kernel.org> wrote: > > On Tue, Mar 19, 2019 at 10:09:13AM -0700, Eric Biggers wrote: > > On Tue, Mar 19, 2019 at 12:54:23PM +0100, Geert Uytterhoeven wrote: > > > When running the sha1-asm crypto selftest on arm with > > > CONFIG_HARDENED_USERCOPY_PAGESPAN=y: > > > > > > usercopy: Kernel memory overwrite attempt detected to spans > > > multiple pages (offset 0, size 42)! > > > ------------[ cut here ]------------ > > > kernel BUG at mm/usercopy.c:102! > > > Internal error: Oops - BUG: 0 [#1] SMP ARM > > > Modules linked in: > > > CPU: 0 PID: 35 Comm: cryptomgr_test Not tainted > > > 5.1.0-rc1-koelsch-01109-gbeb7d6376ecfbf07-dirty #397 > > > Hardware name: Generic R-Car Gen2 (Flattened Device Tree) > > > PC is at usercopy_abort+0x68/0x90 > > > LR is at usercopy_abort+0x68/0x90 > > > pc : [<c030fd60>] lr : [<c030fd60>] psr: 60000013 > > > sp : ea54bc60 ip : 00000010 fp : cccccccd > > > r10: 00000000 r9 : c0e0ce04 r8 : ea54d009 > > > r7 : ea54d00a r6 : 00000000 r5 : 0000002a r4 : c09d1120 > > > r3 : dd6cd422 r2 : dd6cd422 r1 : 2abb4000 r0 : 0000005f > > > Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user > > > Control: 30c5387d Table: 40003000 DAC: fffffffd > > > Process cryptomgr_test (pid: 35, stack limit = 0x(ptrval)) > > > Stack: (0xea54bc60 to 0xea54c000) > > > bc60: c09d1120 c09d1120 c09d1120 00000000 0000002a 0000002a > > > 00000000 c0310060 > > > bc80: 0000002a 00000000 000001c0 00000000 00000000 c0eb11e8 > > > ea54cfe0 ea538c00 > > > bca0: 00000000 ea54cfe0 ebef73e0 0000002a ea538c20 ea54bd84 > > > 0000003a c0427a30 > > > bcc0: ea54bdbc 00000000 00000000 c081cf70 eb074280 c081cf70 > > > 0000002a c081cf80 > > > bce0: 0000000e c07da138 ea54bd0c 00000000 c084061c c04248e8 > > > c0e0a408 eb074240 > > > bd00: eb074200 c04253c8 eb074280 ea550000 00000012 dd6cd422 > > > ebef7480 eb074200 > > > bd20: ea54bd84 c081cf64 ea537200 00000002 00000000 00000014 > > > c084061c c0428c38 > > > bd40: ea54bd84 ea54bdbc c081cd34 00000000 c0e4e4b4 ea538c40 > > > 00000002 eabe4e80 > > > bd60: ea538c00 00000400 ea4f7a00 ea4f7a60 eb074240 00000060 > > > 00000006 c09d544c > > > bd80: 00000038 00000003 00000000 00000038 ea54bd7c 00000001 > > > eb074200 00000000 > > > bda0: 00000000 dead4ead ffffffff ffffffff ea54bdb0 ea54bdb0 > > > 00000000 c081cf70 > > > bdc0: c081ce68 c081ce78 ea4f7480 eb000780 00000dc0 eb000780 > > > c0e4ee80 443e9884 > > > bde0: 6ed23b1c a14aaeba e52951f9 f17046e5 fefefefe fefefefe > > > fefefefe fefefefe > > > be00: eb000780 c04292c4 c0e0a638 60000013 60000013 c0305298 > > > ea4f7a00 c03062bc > > > be20: eb000780 00000cc0 ea4f7a00 dd6cd422 00000cc0 ea538c00 > > > 00000002 eabe4e40 > > > be40: ea537200 00000007 00000000 ea4f7a00 eb074200 c0429314 > > > eb074200 ea538c00 > > > be60: ea4f7a00 0000000a eabe4e80 c084061c c08405fc 00000006 > > > c04dace8 00000006 > > > be80: 00000000 c084065c ea537200 0000000e 00000400 eb04de08 > > > ea4f71a8 c0429420 > > > bea0: 00000400 ea537200 0000000e ea537200 0000000e c0429374 > > > 00000400 ffffffff > > > bec0: 000000a2 c042a414 00000103 c0e0a408 00000000 c0e0a438 > > > c0e5a2a0 c0e5a2a0 > > > bee0: 00000001 00000001 00000017 ffffe000 00000000 60000013 > > > c0e5a2a0 c0269470 > > > bf00: c09c9ed0 ea54bf5c 00000103 00000000 00000000 c0e0a408 > > > ea537280 0000000e > > > bf20: 00000400 c0426500 00000000 eb04de08 ea4f71a8 c02694f4 > > > c09c9ed0 ea54bf5c > > > bf40: ea54bf28 c02699d0 ea54bf5c dd6cd422 ea537200 dd6cd422 > > > c09c9ed0 ea537200 > > > bf60: ea4af1c0 ea54a000 ea537200 c0426500 00000000 eb04de08 > > > ea4f71a8 c0426524 > > > bf80: ea4f7180 c023dcec ea54a000 ea4af1c0 c023dbb4 00000000 > > > 00000000 00000000 > > > bfa0: 00000000 00000000 00000000 c02010d8 00000000 00000000 > > > 00000000 00000000 > > > bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 > > > 00000000 00000000 > > > bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 > > > 00000000 00000000 > > > [<c030fd60>] (usercopy_abort) from [<c0310060>] > > > (__check_object_size+0x2d8/0x448) > > > [<c0310060>] (__check_object_size) from [<c0427a30>] > > > (build_test_sglist+0x268/0x2d8) > > > [<c0427a30>] (build_test_sglist) from [<c0428c38>] > > > (test_hash_vec_cfg+0x110/0x694) > > > [<c0428c38>] (test_hash_vec_cfg) from [<c0429314>] > > > (__alg_test_hash+0x158/0x1b8) > > > [<c0429314>] (__alg_test_hash) from [<c0429420>] > > > (alg_test_hash+0xac/0xf4) > > > [<c0429420>] (alg_test_hash) from [<c042a414>] > > > (alg_test.part.4+0x264/0x2f8) > > > [<c042a414>] (alg_test.part.4) from [<c0426524>] > > > (cryptomgr_test+0x24/0x44) > > > [<c0426524>] (cryptomgr_test) from [<c023dcec>] (kthread+0x138/0x150) > > > [<c023dcec>] (kthread) from [<c02010d8>] (ret_from_fork+0x14/0x3c) > > > Exception stack(0xea54bfb0 to 0xea54bff8) > > > bfa0: 00000000 00000000 > > > 00000000 00000000 > > > bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 > > > 00000000 00000000 > > > bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 > > > Code: e58de000 e98d0012 e1a0100c ebfd6712 (e7f001f2) > > > ---[ end trace 190b3cf48e720f78 ]--- > > > BUG: sleeping function called from invalid context at > > > include/linux/percpu-rwsem.h:34 > > > in_atomic(): 0, irqs_disabled(): 128, pid: 35, name: cryptomgr_test > > > CPU: 0 PID: 35 Comm: cryptomgr_test Tainted: G D > > > 5.1.0-rc1-koelsch-01109-gbeb7d6376ecfbf07-dirty #397 > > > Hardware name: Generic R-Car Gen2 (Flattened Device Tree) > > > [<c020ec74>] (unwind_backtrace) from [<c020ae58>] > > > (show_stack+0x10/0x14) > > > [<c020ae58>] (show_stack) from [<c07c3624>] (dump_stack+0x7c/0x9c) > > > [<c07c3624>] (dump_stack) from [<c0242e14>] > > > (___might_sleep+0xf4/0x158) > > > [<c0242e14>] (___might_sleep) from [<c0230210>] > > > (exit_signals+0x2c/0x258) > > > [<c0230210>] (exit_signals) from [<c0223d6c>] (do_exit+0x114/0xa20) > > > [<c0223d6c>] (do_exit) from [<c020b160>] (die+0x304/0x344) > > > [<c020b160>] (die) from [<c020b388>] (do_undefinstr+0x80/0x190) > > > [<c020b388>] (do_undefinstr) from [<c0201b24>] > > > (__und_svc_finish+0x0/0x3c) > > > Exception stack(0xea54bc10 to 0xea54bc58) > > > bc00: 0000005f 2abb4000 > > > dd6cd422 dd6cd422 > > > bc20: c09d1120 0000002a 00000000 ea54d00a ea54d009 c0e0ce04 > > > 00000000 cccccccd > > > bc40: 00000010 ea54bc60 c030fd60 c030fd60 60000013 ffffffff > > > [<c0201b24>] (__und_svc_finish) from [<c030fd60>] > > > (usercopy_abort+0x68/0x90) > > > [<c030fd60>] (usercopy_abort) from [<c0310060>] > > > (__check_object_size+0x2d8/0x448) > > > [<c0310060>] (__check_object_size) from [<c0427a30>] > > > (build_test_sglist+0x268/0x2d8) > > > [<c0427a30>] (build_test_sglist) from [<c0428c38>] > > > (test_hash_vec_cfg+0x110/0x694) > > > [<c0428c38>] (test_hash_vec_cfg) from [<c0429314>] > > > (__alg_test_hash+0x158/0x1b8) > > > [<c0429314>] (__alg_test_hash) from [<c0429420>] > > > (alg_test_hash+0xac/0xf4) > > > [<c0429420>] (alg_test_hash) from [<c042a414>] > > > (alg_test.part.4+0x264/0x2f8) > > > [<c042a414>] (alg_test.part.4) from [<c0426524>] > > > (cryptomgr_test+0x24/0x44) > > > [<c0426524>] (cryptomgr_test) from [<c023dcec>] (kthread+0x138/0x150) > > > [<c023dcec>] (kthread) from [<c02010d8>] (ret_from_fork+0x14/0x3c) > > > Exception stack(0xea54bfb0 to 0xea54bff8) > > > bfa0: 00000000 00000000 > > > 00000000 00000000 > > > bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 > > > 00000000 00000000 > > > bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 > > > > > > > Well, this must happen with the new (in 5.1) crypto self-tests > > implementation > > for any crypto algorithm when CONFIG_HARDENED_USERCOPY_PAGESPAN=y. I don't > > understand why hardened usercopy considers it a bug though, as there's no > > buffer > > overflow. The crypto tests use copy_from_iter() to copy data into a 2-page > > buffer that was allocated with __get_free_pages(): > > > > __get_free_pages(GFP_KERNEL, 1) > > > > ... where 1 means an order-1 allocation. > > > > If it copies to offset=4064 len=42, for example, then hardened usercopy > > considers it a bug even though the buffer is 8192 bytes long. Why? > > > > It isn't actually copying anything to/from userspace, BTW; it's using > > iov_iter > > with ITER_KVEC. > > > > - Eric > > Kees, any thoughts on why hardened usercopy rejects copies spanning a page > boundary when they seem to be fine?
This is due to missing the compound page marking, if I remember correctly. However, I tend to leave the pagespan test disabled: it really isn't ready for production use -- there are a lot of missing annotations still. -- Kees Cook
