1. 11 Jan, 2019 24 commits
  2. 10 Jan, 2019 11 commits
    • Eric Biggers's avatar
      crypto: sm3 - fix undefined shift by >= width of value · d45a90cb
      Eric Biggers authored
      sm3_compress() calls rol32() with shift >= 32, which causes undefined
      behavior.  This is easily detected by enabling CONFIG_UBSAN.
      
      Explicitly AND with 31 to make the behavior well defined.
      
      Fixes: 4f0fc160 ("crypto: sm3 - add OSCCA SM3 secure hash")
      Cc: <stable@vger.kernel.org> # v4.15+
      Cc: Gilad Ben-Yossef <gilad@benyossef.com>
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      d45a90cb
    • Christophe Leroy's avatar
      crypto: talitos - fix ablkcipher for CONFIG_VMAP_STACK · 1bea445b
      Christophe Leroy authored
      [    2.364486] WARNING: CPU: 0 PID: 60 at ./arch/powerpc/include/asm/io.h:837 dma_nommu_map_page+0x44/0xd4
      [    2.373579] CPU: 0 PID: 60 Comm: cryptomgr_test Tainted: G        W         4.20.0-rc5-00560-g6bfb52e23a00-dirty #531
      [    2.384740] NIP:  c000c540 LR: c000c584 CTR: 00000000
      [    2.389743] REGS: c95abab0 TRAP: 0700   Tainted: G        W          (4.20.0-rc5-00560-g6bfb52e23a00-dirty)
      [    2.400042] MSR:  00029032 <EE,ME,IR,DR,RI>  CR: 24042204  XER: 00000000
      [    2.406669]
      [    2.406669] GPR00: c02f2244 c95abb60 c6262990 c95abd80 0000256a 00000001 00000001 00000001
      [    2.406669] GPR08: 00000000 00002000 00000010 00000010 24042202 00000000 00000100 c95abd88
      [    2.406669] GPR16: 00000000 c05569d4 00000001 00000010 c95abc88 c0615664 00000004 00000000
      [    2.406669] GPR24: 00000010 c95abc88 c95abc88 00000000 c61ae210 c7ff6d40 c61ae210 00003d68
      [    2.441559] NIP [c000c540] dma_nommu_map_page+0x44/0xd4
      [    2.446720] LR [c000c584] dma_nommu_map_page+0x88/0xd4
      [    2.451762] Call Trace:
      [    2.454195] [c95abb60] [82000808] 0x82000808 (unreliable)
      [    2.459572] [c95abb80] [c02f2244] talitos_edesc_alloc+0xbc/0x3c8
      [    2.465493] [c95abbb0] [c02f2600] ablkcipher_edesc_alloc+0x4c/0x5c
      [    2.471606] [c95abbd0] [c02f4ed0] ablkcipher_encrypt+0x20/0x64
      [    2.477389] [c95abbe0] [c02023b0] __test_skcipher+0x4bc/0xa08
      [    2.483049] [c95abe00] [c0204b60] test_skcipher+0x2c/0xcc
      [    2.488385] [c95abe20] [c0204c48] alg_test_skcipher+0x48/0xbc
      [    2.494064] [c95abe40] [c0205cec] alg_test+0x164/0x2e8
      [    2.499142] [c95abf00] [c0200dec] cryptomgr_test+0x48/0x50
      [    2.504558] [c95abf10] [c0039ff4] kthread+0xe4/0x110
      [    2.509471] [c95abf40] [c000e1d0] ret_from_kernel_thread+0x14/0x1c
      [    2.515532] Instruction dump:
      [    2.518468] 7c7e1b78 7c9d2378 7cbf2b78 41820054 3d20c076 8089c200 3d20c076 7c84e850
      [    2.526127] 8129c204 7c842e70 7f844840 419c0008 <0fe00000> 2f9e0000 54847022 7c84fa14
      [    2.533960] ---[ end trace bf78d94af73fe3b8 ]---
      [    2.539123] talitos ff020000.crypto: master data transfer error
      [    2.544775] talitos ff020000.crypto: TEA error: ISR 0x20000000_00000040
      [    2.551625] alg: skcipher: encryption failed on test 1 for ecb-aes-talitos: ret=22
      
      IV cannot be on stack when CONFIG_VMAP_STACK is selected because the stack
      cannot be DMA mapped anymore.
      
      This patch copies the IV into the extended descriptor.
      
      Fixes: 4de9d0b5 ("crypto: talitos - Add ablkcipher algorithms")
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
      Reviewed-by: default avatarHoria Geantă <horia.geanta@nxp.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      1bea445b
    • Christophe Leroy's avatar
      crypto: talitos - reorder code in talitos_edesc_alloc() · c56c2e17
      Christophe Leroy authored
      This patch moves the mapping of IV after the kmalloc(). This
      avoids having to unmap in case kmalloc() fails.
      Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
      Reviewed-by: default avatarHoria Geantă <horia.geanta@nxp.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      c56c2e17
    • Eric Biggers's avatar
      crypto: adiantum - initialize crypto_spawn::inst · 6db43410
      Eric Biggers authored
      crypto_grab_*() doesn't set crypto_spawn::inst, so templates must set it
      beforehand.  Otherwise it will be left NULL, which causes a crash in
      certain cases where algorithms are dynamically loaded/unloaded.  E.g.
      with CONFIG_CRYPTO_CHACHA20_X86_64=m, the following caused a crash:
      
          insmod chacha-x86_64.ko
          python -c 'import socket; socket.socket(socket.AF_ALG, 5, 0).bind(("skcipher", "adiantum(xchacha12,aes)"))'
          rmmod chacha-x86_64.ko
          python -c 'import socket; socket.socket(socket.AF_ALG, 5, 0).bind(("skcipher", "adiantum(xchacha12,aes)"))'
      
      Fixes: 059c2a4d ("crypto: adiantum - add Adiantum support")
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      6db43410
    • Dan Carpenter's avatar
      crypto: cavium/nitrox - Use after free in process_response_list() · 06bbf753
      Dan Carpenter authored
      We free "sr" and then dereference it on the next line.
      
      Fixes: c9613335 ("crypto: cavium/nitrox - Added AEAD cipher support")
      Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      06bbf753
    • Harsh Jain's avatar
      crypto: authencesn - Avoid twice completion call in decrypt path · a7773363
      Harsh Jain authored
      Authencesn template in decrypt path unconditionally calls aead_request_complete
      after ahash_verify which leads to following kernel panic in after decryption.
      
      [  338.539800] BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
      [  338.548372] PGD 0 P4D 0
      [  338.551157] Oops: 0000 [#1] SMP PTI
      [  338.554919] CPU: 0 PID: 0 Comm: swapper/0 Kdump: loaded Tainted: G        W I       4.19.7+ #13
      [  338.564431] Hardware name: Supermicro X8ST3/X8ST3, BIOS 2.0        07/29/10
      [  338.572212] RIP: 0010:esp_input_done2+0x350/0x410 [esp4]
      [  338.578030] Code: ff 0f b6 68 10 48 8b 83 c8 00 00 00 e9 8e fe ff ff 8b 04 25 04 00 00 00 83 e8 01 48 98 48 8b 3c c5 10 00 00 00 e9 f7 fd ff ff <8b> 04 25 04 00 00 00 83 e8 01 48 98 4c 8b 24 c5 10 00 00 00 e9 3b
      [  338.598547] RSP: 0018:ffff911c97803c00 EFLAGS: 00010246
      [  338.604268] RAX: 0000000000000002 RBX: ffff911c4469ee00 RCX: 0000000000000000
      [  338.612090] RDX: 0000000000000000 RSI: 0000000000000130 RDI: ffff911b87c20400
      [  338.619874] RBP: 0000000000000000 R08: ffff911b87c20498 R09: 000000000000000a
      [  338.627610] R10: 0000000000000001 R11: 0000000000000004 R12: 0000000000000000
      [  338.635402] R13: ffff911c89590000 R14: ffff911c91730000 R15: 0000000000000000
      [  338.643234] FS:  0000000000000000(0000) GS:ffff911c97800000(0000) knlGS:0000000000000000
      [  338.652047] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      [  338.658299] CR2: 0000000000000004 CR3: 00000001ec20a000 CR4: 00000000000006f0
      [  338.666382] Call Trace:
      [  338.669051]  <IRQ>
      [  338.671254]  esp_input_done+0x12/0x20 [esp4]
      [  338.675922]  chcr_handle_resp+0x3b5/0x790 [chcr]
      [  338.680949]  cpl_fw6_pld_handler+0x37/0x60 [chcr]
      [  338.686080]  chcr_uld_rx_handler+0x22/0x50 [chcr]
      [  338.691233]  uldrx_handler+0x8c/0xc0 [cxgb4]
      [  338.695923]  process_responses+0x2f0/0x5d0 [cxgb4]
      [  338.701177]  ? bitmap_find_next_zero_area_off+0x3a/0x90
      [  338.706882]  ? matrix_alloc_area.constprop.7+0x60/0x90
      [  338.712517]  ? apic_update_irq_cfg+0x82/0xf0
      [  338.717177]  napi_rx_handler+0x14/0xe0 [cxgb4]
      [  338.722015]  net_rx_action+0x2aa/0x3e0
      [  338.726136]  __do_softirq+0xcb/0x280
      [  338.730054]  irq_exit+0xde/0xf0
      [  338.733504]  do_IRQ+0x54/0xd0
      [  338.736745]  common_interrupt+0xf/0xf
      
      Fixes: 104880a6 ("crypto: authencesn - Convert to new AEAD...")
      Signed-off-by: default avatarHarsh Jain <harsh@chelsio.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      a7773363
    • Horia Geantă's avatar
      crypto: caam - fix SHA support detection · 2dd3fde4
      Horia Geantă authored
      The addition of Chacha20 + Poly1305 authenc support inadvertently broke
      detection of algorithms supported by MDHA (Message Digest Hardware
      Accelerator), fix it.
      
      Fixes: d6bbd4ee ("crypto: caam/jr - add support for Chacha20 + Poly1305")
      Signed-off-by: default avatarHoria Geantă <horia.geanta@nxp.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      2dd3fde4
    • Aymen Sghaier's avatar
      crypto: caam - fix zero-length buffer DMA mapping · 04e6d25c
      Aymen Sghaier authored
      Recent changes - probably DMA API related (generic and/or arm64-specific) -
      exposed a case where driver maps a zero-length buffer:
      ahash_init()->ahash_update()->ahash_final() with a zero-length string to
      hash
      
      kernel BUG at kernel/dma/swiotlb.c:475!
      Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
      Modules linked in:
      CPU: 2 PID: 1823 Comm: cryptomgr_test Not tainted 4.20.0-rc1-00108-g00c9fe37 #1
      Hardware name: LS1046A RDB Board (DT)
      pstate: 80000005 (Nzcv daif -PAN -UAO)
      pc : swiotlb_tbl_map_single+0x170/0x2b8
      lr : swiotlb_map_page+0x134/0x1f8
      sp : ffff00000f79b8f0
      x29: ffff00000f79b8f0 x28: 0000000000000000
      x27: ffff0000093d0000 x26: 0000000000000000
      x25: 00000000001f3ffe x24: 0000000000200000
      x23: 0000000000000000 x22: 00000009f2c538c0
      x21: ffff800970aeb410 x20: 0000000000000001
      x19: ffff800970aeb410 x18: 0000000000000007
      x17: 000000000000000e x16: 0000000000000001
      x15: 0000000000000019 x14: c32cb8218a167fe8
      x13: ffffffff00000000 x12: ffff80097fdae348
      x11: 0000800976bca000 x10: 0000000000000010
      x9 : 0000000000000000 x8 : ffff0000091fd6c8
      x7 : 0000000000000000 x6 : 00000009f2c538bf
      x5 : 0000000000000000 x4 : 0000000000000001
      x3 : 0000000000000000 x2 : 00000009f2c538c0
      x1 : 00000000f9fff000 x0 : 0000000000000000
      Process cryptomgr_test (pid: 1823, stack limit = 0x(____ptrval____))
      Call trace:
       swiotlb_tbl_map_single+0x170/0x2b8
       swiotlb_map_page+0x134/0x1f8
       ahash_final_no_ctx+0xc4/0x6cc
       ahash_final+0x10/0x18
       crypto_ahash_op+0x30/0x84
       crypto_ahash_final+0x14/0x1c
       __test_hash+0x574/0xe0c
       test_hash+0x28/0x80
       __alg_test_hash+0x84/0xd0
       alg_test_hash+0x78/0x144
       alg_test.part.30+0x12c/0x2b4
       alg_test+0x3c/0x68
       cryptomgr_test+0x44/0x4c
       kthread+0xfc/0x128
       ret_from_fork+0x10/0x18
      Code: d34bfc18 2a1a03f7 1a9f8694 35fff89a (d4210000)
      
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAymen Sghaier <aymen.sghaier@nxp.com>
      Signed-off-by: default avatarHoria Geantă <horia.geanta@nxp.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      04e6d25c
    • Eric Biggers's avatar
      crypto: ccree - convert to use crypto_authenc_extractkeys() · dc95b535
      Eric Biggers authored
      Convert the ccree crypto driver to use crypto_authenc_extractkeys() so
      that it picks up the fix for broken validation of rtattr::rta_len.
      
      Fixes: ff27e85a ("crypto: ccree - add AEAD support")
      Cc: <stable@vger.kernel.org> # v4.17+
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      dc95b535
    • Eric Biggers's avatar
      crypto: bcm - convert to use crypto_authenc_extractkeys() · ab57b335
      Eric Biggers authored
      Convert the bcm crypto driver to use crypto_authenc_extractkeys() so
      that it picks up the fix for broken validation of rtattr::rta_len.
      
      This also fixes the DES weak key check to actually be done on the right
      key. (It was checking the authentication key, not the encryption key...)
      
      Fixes: 9d12ba86 ("crypto: brcm - Add Broadcom SPU driver")
      Cc: <stable@vger.kernel.org> # v4.11+
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      ab57b335
    • Eric Biggers's avatar
      crypto: authenc - fix parsing key with misaligned rta_len · 8f9c4693
      Eric Biggers authored
      Keys for "authenc" AEADs are formatted as an rtattr containing a 4-byte
      'enckeylen', followed by an authentication key and an encryption key.
      crypto_authenc_extractkeys() parses the key to find the inner keys.
      
      However, it fails to consider the case where the rtattr's payload is
      longer than 4 bytes but not 4-byte aligned, and where the key ends
      before the next 4-byte aligned boundary.  In this case, 'keylen -=
      RTA_ALIGN(rta->rta_len);' underflows to a value near UINT_MAX.  This
      causes a buffer overread and crash during crypto_ahash_setkey().
      
      Fix it by restricting the rtattr payload to the expected size.
      
      Reproducer using AF_ALG:
      
      	#include <linux/if_alg.h>
      	#include <linux/rtnetlink.h>
      	#include <sys/socket.h>
      
      	int main()
      	{
      		int fd;
      		struct sockaddr_alg addr = {
      			.salg_type = "aead",
      			.salg_name = "authenc(hmac(sha256),cbc(aes))",
      		};
      		struct {
      			struct rtattr attr;
      			__be32 enckeylen;
      			char keys[1];
      		} __attribute__((packed)) key = {
      			.attr.rta_len = sizeof(key),
      			.attr.rta_type = 1 /* CRYPTO_AUTHENC_KEYA_PARAM */,
      		};
      
      		fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
      		bind(fd, (void *)&addr, sizeof(addr));
      		setsockopt(fd, SOL_ALG, ALG_SET_KEY, &key, sizeof(key));
      	}
      
      It caused:
      
      	BUG: unable to handle kernel paging request at ffff88007ffdc000
      	PGD 2e01067 P4D 2e01067 PUD 2e04067 PMD 2e05067 PTE 0
      	Oops: 0000 [#1] SMP
      	CPU: 0 PID: 883 Comm: authenc Not tainted 4.20.0-rc1-00108-g00c9fe37 #13
      	Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014
      	RIP: 0010:sha256_ni_transform+0xb3/0x330 arch/x86/crypto/sha256_ni_asm.S:155
      	[...]
      	Call Trace:
      	 sha256_ni_finup+0x10/0x20 arch/x86/crypto/sha256_ssse3_glue.c:321
      	 crypto_shash_finup+0x1a/0x30 crypto/shash.c:178
      	 shash_digest_unaligned+0x45/0x60 crypto/shash.c:186
      	 crypto_shash_digest+0x24/0x40 crypto/shash.c:202
      	 hmac_setkey+0x135/0x1e0 crypto/hmac.c:66
      	 crypto_shash_setkey+0x2b/0xb0 crypto/shash.c:66
      	 shash_async_setkey+0x10/0x20 crypto/shash.c:223
      	 crypto_ahash_setkey+0x2d/0xa0 crypto/ahash.c:202
      	 crypto_authenc_setkey+0x68/0x100 crypto/authenc.c:96
      	 crypto_aead_setkey+0x2a/0xc0 crypto/aead.c:62
      	 aead_setkey+0xc/0x10 crypto/algif_aead.c:526
      	 alg_setkey crypto/af_alg.c:223 [inline]
      	 alg_setsockopt+0xfe/0x130 crypto/af_alg.c:256
      	 __sys_setsockopt+0x6d/0xd0 net/socket.c:1902
      	 __do_sys_setsockopt net/socket.c:1913 [inline]
      	 __se_sys_setsockopt net/socket.c:1910 [inline]
      	 __x64_sys_setsockopt+0x1f/0x30 net/socket.c:1910
      	 do_syscall_64+0x4a/0x180 arch/x86/entry/common.c:290
      	 entry_SYSCALL_64_after_hwframe+0x49/0xbe
      
      Fixes: e236d4a8 ("[CRYPTO] authenc: Move enckeylen into key itself")
      Cc: <stable@vger.kernel.org> # v2.6.25+
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      8f9c4693
  3. 07 Jan, 2019 3 commits
    • Linus Torvalds's avatar
      Linux 5.0-rc1 · bfeffd15
      Linus Torvalds authored
      bfeffd15
    • Linus Torvalds's avatar
      Merge tag 'kbuild-v4.21-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild · 85e1ffbd
      Linus Torvalds authored
      Pull more Kbuild updates from Masahiro Yamada:
      
       - improve boolinit.cocci and use_after_iter.cocci semantic patches
      
       - fix alignment for kallsyms
      
       - move 'asm goto' compiler test to Kconfig and clean up jump_label
         CONFIG option
      
       - generate asm-generic wrappers automatically if arch does not
         implement mandatory UAPI headers
      
       - remove redundant generic-y defines
      
       - misc cleanups
      
      * tag 'kbuild-v4.21-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
        kconfig: rename generated .*conf-cfg to *conf-cfg
        kbuild: remove unnecessary stubs for archheader and archscripts
        kbuild: use assignment instead of define ... endef for filechk_* rules
        arch: remove redundant UAPI generic-y defines
        kbuild: generate asm-generic wrappers if mandatory headers are missing
        arch: remove stale comments "UAPI Header export list"
        riscv: remove redundant kernel-space generic-y
        kbuild: change filechk to surround the given command with { }
        kbuild: remove redundant target cleaning on failure
        kbuild: clean up rule_dtc_dt_yaml
        kbuild: remove UIMAGE_IN and UIMAGE_OUT
        jump_label: move 'asm goto' support test to Kconfig
        kallsyms: lower alignment on ARM
        scripts: coccinelle: boolinit: drop warnings on named constants
        scripts: coccinelle: check for redeclaration
        kconfig: remove unused "file" field of yylval union
        nds32: remove redundant kernel-space generic-y
        nios2: remove unneeded HAS_DMA define
      85e1ffbd
    • Linus Torvalds's avatar
      Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · ac5eed2b
      Linus Torvalds authored
      Pull perf tooling updates form Ingo Molnar:
       "A final batch of perf tooling changes: mostly fixes and small
        improvements"
      
      * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits)
        perf session: Add comment for perf_session__register_idle_thread()
        perf thread-stack: Fix thread stack processing for the idle task
        perf thread-stack: Allocate an array of thread stacks
        perf thread-stack: Factor out thread_stack__init()
        perf thread-stack: Allow for a thread stack array
        perf thread-stack: Avoid direct reference to the thread's stack
        perf thread-stack: Tidy thread_stack__bottom() usage
        perf thread-stack: Simplify some code in thread_stack__process()
        tools gpio: Allow overriding CFLAGS
        tools power turbostat: Override CFLAGS assignments and add LDFLAGS to build command
        tools thermal tmon: Allow overriding CFLAGS assignments
        tools power x86_energy_perf_policy: Override CFLAGS assignments and add LDFLAGS to build command
        perf c2c: Increase the HITM ratio limit for displayed cachelines
        perf c2c: Change the default coalesce setup
        perf trace beauty ioctl: Beautify USBDEVFS_ commands
        perf trace beauty: Export function to get the files for a thread
        perf trace: Wire up ioctl's USBDEBFS_ cmd table generator
        perf beauty ioctl: Add generator for USBDEVFS_ ioctl commands
        tools headers uapi: Grab a copy of usbdevice_fs.h
        perf trace: Store the major number for a file when storing its pathname
        ...
      ac5eed2b
  4. 06 Jan, 2019 2 commits
    • Linus Torvalds's avatar
      Change mincore() to count "mapped" pages rather than "cached" pages · 574823bf
      Linus Torvalds authored
      The semantics of what "in core" means for the mincore() system call are
      somewhat unclear, but Linux has always (since 2.3.52, which is when
      mincore() was initially done) treated it as "page is available in page
      cache" rather than "page is mapped in the mapping".
      
      The problem with that traditional semantic is that it exposes a lot of
      system cache state that it really probably shouldn't, and that users
      shouldn't really even care about.
      
      So let's try to avoid that information leak by simply changing the
      semantics to be that mincore() counts actual mapped pages, not pages
      that might be cheaply mapped if they were faulted (note the "might be"
      part of the old semantics: being in the cache doesn't actually guarantee
      that you can access them without IO anyway, since things like network
      filesystems may have to revalidate the cache before use).
      
      In many ways the old semantics were somewhat insane even aside from the
      information leak issue.  From the very beginning (and that beginning is
      a long time ago: 2.3.52 was released in March 2000, I think), the code
      had a comment saying
      
        Later we can get more picky about what "in core" means precisely.
      
      and this is that "later".  Admittedly it is much later than is really
      comfortable.
      
      NOTE! This is a real semantic change, and it is for example known to
      change the output of "fincore", since that program literally does a
      mmmap without populating it, and then doing "mincore()" on that mapping
      that doesn't actually have any pages in it.
      
      I'm hoping that nobody actually has any workflow that cares, and the
      info leak is real.
      
      We may have to do something different if it turns out that people have
      valid reasons to want the old semantics, and if we can limit the
      information leak sanely.
      
      Cc: Kevin Easton <kevin@guarana.org>
      Cc: Jiri Kosina <jikos@kernel.org>
      Cc: Masatake YAMATO <yamato@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Greg KH <gregkh@linuxfoundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      574823bf
    • Linus Torvalds's avatar
      Fix 'acccess_ok()' on alpha and SH · 94bd8a05
      Linus Torvalds authored
      Commit 594cc251 ("make 'user_access_begin()' do 'access_ok()'")
      broke both alpha and SH booting in qemu, as noticed by Guenter Roeck.
      
      It turns out that the bug wasn't actually in that commit itself (which
      would have been surprising: it was mostly a no-op), but in how the
      addition of access_ok() to the strncpy_from_user() and strnlen_user()
      functions now triggered the case where those functions would test the
      access of the very last byte of the user address space.
      
      The string functions actually did that user range test before too, but
      they did it manually by just comparing against user_addr_max().  But
      with user_access_begin() doing the check (using "access_ok()"), it now
      exposed problems in the architecture implementations of that function.
      
      For example, on alpha, the access_ok() helper macro looked like this:
      
        #define __access_ok(addr, size) \
              ((get_fs().seg & (addr | size | (addr+size))) == 0)
      
      and what it basically tests is of any of the high bits get set (the
      USER_DS masking value is 0xfffffc0000000000).
      
      And that's completely wrong for the "addr+size" check.  Because it's
      off-by-one for the case where we check to the very end of the user
      address space, which is exactly what the strn*_user() functions do.
      
      Why? Because "addr+size" will be exactly the size of the address space,
      so trying to access the last byte of the user address space will fail
      the __access_ok() check, even though it shouldn't.  As a result, the
      user string accessor functions failed consistently - because they
      literally don't know how long the string is going to be, and the max
      access is going to be that last byte of the user address space.
      
      Side note: that alpha macro is buggy for another reason too - it re-uses
      the arguments twice.
      
      And SH has another version of almost the exact same bug:
      
        #define __addr_ok(addr) \
              ((unsigned long __force)(addr) < current_thread_info()->addr_limit.seg)
      
      so far so good: yes, a user address must be below the limit.  But then:
      
        #define __access_ok(addr, size)         \
              (__addr_ok((addr) + (size)))
      
      is wrong with the exact same off-by-one case: the case when "addr+size"
      is exactly _equal_ to the limit is actually perfectly fine (think "one
      byte access at the last address of the user address space")
      
      The SH version is actually seriously buggy in another way: it doesn't
      actually check for overflow, even though it did copy the _comment_ that
      talks about overflow.
      
      So it turns out that both SH and alpha actually have completely buggy
      implementations of access_ok(), but they happened to work in practice
      (although the SH overflow one is a serious serious security bug, not
      that anybody likely cares about SH security).
      
      This fixes the problems by using a similar macro on both alpha and SH.
      It isn't trying to be clever, the end address is based on this logic:
      
              unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b;
      
      which basically says "add start and length, and then subtract one unless
      the length was zero".  We can't subtract one for a zero length, or we'd
      just hit an underflow instead.
      
      For a lot of access_ok() users the length is a constant, so this isn't
      actually as expensive as it initially looks.
      Reported-and-tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      94bd8a05