linux-stable.git/include, branch v3.2.97 Linux kernel stable tree crypto: hmac - require that the underlying hash algorithm is unkeyed 2018-01-01T20:51:05+00:00 Eric Biggers ebiggers@google.com 2017-11-29T02:01:38+00:00 a63785d3294e9d7704db04500400fd8bb4b59a69 commit af3ff8045bbf3e32f1a448542e73abb4c8ceb6f1 upstream. Because the HMAC template didn't check that its underlying hash algorithm is unkeyed, trying to use "hmac(hmac(sha3-512-generic))" through AF_ALG or through KEYCTL_DH_COMPUTE resulted in the inner HMAC being used without having been keyed, resulting in sha3_update() being called without sha3_init(), causing a stack buffer overflow. This is a very old bug, but it seems to have only started causing real problems when SHA-3 support was added (requires CONFIG_CRYPTO_SHA3) because the innermost hash's state is ->import()ed from a zeroed buffer, and it just so happens that other hash algorithms are fine with that, but SHA-3 is not. However, there could be arch or hardware-dependent hash algorithms also affected; I couldn't test everything. Fix the bug by introducing a function crypto_shash_alg_has_setkey() which tests whether a shash algorithm is keyed. Then update the HMAC template to require that its underlying hash algorithm is unkeyed. Here is a reproducer: #include <linux/if_alg.h> #include <sys/socket.h> int main() { int algfd; struct sockaddr_alg addr = { .salg_type = "hash", .salg_name = "hmac(hmac(sha3-512-generic))", }; char key[4096] = { 0 }; algfd = socket(AF_ALG, SOCK_SEQPACKET, 0); bind(algfd, (const struct sockaddr *)&addr, sizeof(addr)); setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key)); } Here was the KASAN report from syzbot: BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:341 [inline] BUG: KASAN: stack-out-of-bounds in sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 Write of size 4096 at addr ffff8801cca07c40 by task syzkaller076574/3044 CPU: 1 PID: 3044 Comm: syzkaller076574 Not tainted 4.14.0-mm1+ #25 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x25b/0x340 mm/kasan/report.c:409 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x137/0x190 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 memcpy include/linux/string.h:341 [inline] sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 crypto_shash_update+0xcb/0x220 crypto/shash.c:109 shash_finup_unaligned+0x2a/0x60 crypto/shash.c:151 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 hmac_finup+0x182/0x330 crypto/hmac.c:152 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 shash_digest_unaligned+0x9e/0xd0 crypto/shash.c:172 crypto_shash_digest+0xc4/0x120 crypto/shash.c:186 hmac_setkey+0x36a/0x690 crypto/hmac.c:66 crypto_shash_setkey+0xad/0x190 crypto/shash.c:64 shash_async_setkey+0x47/0x60 crypto/shash.c:207 crypto_ahash_setkey+0xaf/0x180 crypto/ahash.c:200 hash_setkey+0x40/0x90 crypto/algif_hash.c:446 alg_setkey crypto/af_alg.c:221 [inline] alg_setsockopt+0x2a1/0x350 crypto/af_alg.c:254 SYSC_setsockopt net/socket.c:1851 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1830 entry_SYSCALL_64_fastpath+0x1f/0x96 Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit af3ff8045bbf3e32f1a448542e73abb4c8ceb6f1 upstream.

Because the HMAC template didn't check that its underlying hash
algorithm is unkeyed, trying to use "hmac(hmac(sha3-512-generic))"
through AF_ALG or through KEYCTL_DH_COMPUTE resulted in the inner HMAC
being used without having been keyed, resulting in sha3_update() being
called without sha3_init(), causing a stack buffer overflow.

This is a very old bug, but it seems to have only started causing real
problems when SHA-3 support was added (requires CONFIG_CRYPTO_SHA3)
because the innermost hash's state is ->import()ed from a zeroed buffer,
and it just so happens that other hash algorithms are fine with that,
but SHA-3 is not.  However, there could be arch or hardware-dependent
hash algorithms also affected; I couldn't test everything.

Fix the bug by introducing a function crypto_shash_alg_has_setkey()
which tests whether a shash algorithm is keyed.  Then update the HMAC
template to require that its underlying hash algorithm is unkeyed.

Here is a reproducer:

    #include <linux/if_alg.h>
    #include <sys/socket.h>

    int main()
    {
        int algfd;
        struct sockaddr_alg addr = {
            .salg_type = "hash",
            .salg_name = "hmac(hmac(sha3-512-generic))",
        };
        char key[4096] = { 0 };

        algfd = socket(AF_ALG, SOCK_SEQPACKET, 0);
        bind(algfd, (const struct sockaddr *)&addr, sizeof(addr));
        setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key));
    }

Here was the KASAN report from syzbot:

    BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:341  [inline]
    BUG: KASAN: stack-out-of-bounds in sha3_update+0xdf/0x2e0  crypto/sha3_generic.c:161
    Write of size 4096 at addr ffff8801cca07c40 by task syzkaller076574/3044

    CPU: 1 PID: 3044 Comm: syzkaller076574 Not tainted 4.14.0-mm1+ #25
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  Google 01/01/2011
    Call Trace:
      __dump_stack lib/dump_stack.c:17 [inline]
      dump_stack+0x194/0x257 lib/dump_stack.c:53
      print_address_description+0x73/0x250 mm/kasan/report.c:252
      kasan_report_error mm/kasan/report.c:351 [inline]
      kasan_report+0x25b/0x340 mm/kasan/report.c:409
      check_memory_region_inline mm/kasan/kasan.c:260 [inline]
      check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
      memcpy+0x37/0x50 mm/kasan/kasan.c:303
      memcpy include/linux/string.h:341 [inline]
      sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161
      crypto_shash_update+0xcb/0x220 crypto/shash.c:109
      shash_finup_unaligned+0x2a/0x60 crypto/shash.c:151
      crypto_shash_finup+0xc4/0x120 crypto/shash.c:165
      hmac_finup+0x182/0x330 crypto/hmac.c:152
      crypto_shash_finup+0xc4/0x120 crypto/shash.c:165
      shash_digest_unaligned+0x9e/0xd0 crypto/shash.c:172
      crypto_shash_digest+0xc4/0x120 crypto/shash.c:186
      hmac_setkey+0x36a/0x690 crypto/hmac.c:66
      crypto_shash_setkey+0xad/0x190 crypto/shash.c:64
      shash_async_setkey+0x47/0x60 crypto/shash.c:207
      crypto_ahash_setkey+0xaf/0x180 crypto/ahash.c:200
      hash_setkey+0x40/0x90 crypto/algif_hash.c:446
      alg_setkey crypto/af_alg.c:221 [inline]
      alg_setsockopt+0x2a1/0x350 crypto/af_alg.c:254
      SYSC_setsockopt net/socket.c:1851 [inline]
      SyS_setsockopt+0x189/0x360 net/socket.c:1830
      entry_SYSCALL_64_fastpath+0x1f/0x96

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
KVM: Fix stack-out-of-bounds read in write_mmio 2018-01-01T20:51:04+00:00 Wanpeng Li wanpeng.li@hotmail.com 2017-12-15T01:40:50+00:00 26a8a3c531ae847048ee9126f07cb07424bd4724 commit e39d200fa5bf5b94a0948db0dae44c1b73b84a56 upstream. Reported by syzkaller: BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm] Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298 CPU: 6 PID: 32298 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #18 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 Call Trace: dump_stack+0xab/0xe1 print_address_description+0x6b/0x290 kasan_report+0x28a/0x370 write_mmio+0x11e/0x270 [kvm] emulator_read_write_onepage+0x311/0x600 [kvm] emulator_read_write+0xef/0x240 [kvm] emulator_fix_hypercall+0x105/0x150 [kvm] em_hypercall+0x2b/0x80 [kvm] x86_emulate_insn+0x2b1/0x1640 [kvm] x86_emulate_instruction+0x39a/0xb90 [kvm] handle_exception+0x1b4/0x4d0 [kvm_intel] vcpu_enter_guest+0x15a0/0x2640 [kvm] kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm] kvm_vcpu_ioctl+0x479/0x880 [kvm] do_vfs_ioctl+0x142/0x9a0 SyS_ioctl+0x74/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall) to the guest memory, however, write_mmio tracepoint always prints 8 bytes through *(u64 *)val since kvm splits the mmio access into 8 bytes. This leaks 5 bytes from the kernel stack (CVE-2017-17741). This patch fixes it by just accessing the bytes which we operate on. Before patch: syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f After patch: syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [bwh: Backported to 3.2: - Drop ARM changes - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit e39d200fa5bf5b94a0948db0dae44c1b73b84a56 upstream.

Reported by syzkaller:

  BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm]
  Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298

  CPU: 6 PID: 32298 Comm: syz-executor Tainted: G           OE    4.15.0-rc2+ #18
  Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016
  Call Trace:
   dump_stack+0xab/0xe1
   print_address_description+0x6b/0x290
   kasan_report+0x28a/0x370
   write_mmio+0x11e/0x270 [kvm]
   emulator_read_write_onepage+0x311/0x600 [kvm]
   emulator_read_write+0xef/0x240 [kvm]
   emulator_fix_hypercall+0x105/0x150 [kvm]
   em_hypercall+0x2b/0x80 [kvm]
   x86_emulate_insn+0x2b1/0x1640 [kvm]
   x86_emulate_instruction+0x39a/0xb90 [kvm]
   handle_exception+0x1b4/0x4d0 [kvm_intel]
   vcpu_enter_guest+0x15a0/0x2640 [kvm]
   kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm]
   kvm_vcpu_ioctl+0x479/0x880 [kvm]
   do_vfs_ioctl+0x142/0x9a0
   SyS_ioctl+0x74/0x80
   entry_SYSCALL_64_fastpath+0x23/0x9a

The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall)
to the guest memory, however, write_mmio tracepoint always prints 8 bytes
through *(u64 *)val since kvm splits the mmio access into 8 bytes. This
leaks 5 bytes from the kernel stack (CVE-2017-17741).  This patch fixes
it by just accessing the bytes which we operate on.

Before patch:

syz-executor-5567  [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f

After patch:

syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.2:
 - Drop ARM changes
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Bluetooth: hidp: verify l2cap sockets 2018-01-01T20:51:03+00:00 David Herrmann dh.herrmann@gmail.com 2013-04-05T12:57:34+00:00 6b369a5d1ed6c5c04a76db01c21802e1ca11ec82 commit b3916db32c4a3124eee9f3742a2f4723731d7602 upstream. We need to verify that the given sockets actually are l2cap sockets. If they aren't, we are not supposed to access bt_sk(sock) and we shouldn't start the session if the offsets turn out to be valid local BT addresses. That is, if someone passes a TCP socket to HIDCONNADD, then we access some random offset in the TCP socket (which isn't even guaranteed to be valid). Fix this by checking that the socket is an l2cap socket. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit b3916db32c4a3124eee9f3742a2f4723731d7602 upstream.

We need to verify that the given sockets actually are l2cap sockets. If
they aren't, we are not supposed to access bt_sk(sock) and we shouldn't
start the session if the offsets turn out to be valid local BT addresses.

That is, if someone passes a TCP socket to HIDCONNADD, then we access some
random offset in the TCP socket (which isn't even guaranteed to be valid).

Fix this by checking that the socket is an l2cap socket.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ALSA: seq: Avoid invalid lockdep class warning 2018-01-01T20:51:02+00:00 Takashi Iwai tiwai@suse.de 2017-11-06T19:16:50+00:00 8cd91d715b641d31b4b79f6dde178d1e3032988b commit 3510c7aa069aa83a2de6dab2b41401a198317bdc upstream. The recent fix for adding rwsem nesting annotation was using the given "hop" argument as the lock subclass key. Although the idea itself works, it may trigger a kernel warning like: BUG: looking up invalid subclass: 8 .... since the lockdep has a smaller number of subclasses (8) than we currently allow for the hops there (10). The current definition is merely a sanity check for avoiding the too deep delivery paths, and the 8 hops are already enough. So, as a quick fix, just follow the max hops as same as the max lockdep subclasses. Fixes: 1f20f9ff57ca ("ALSA: seq: Fix nested rwsem annotation for lockdep splat") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 3510c7aa069aa83a2de6dab2b41401a198317bdc upstream.

The recent fix for adding rwsem nesting annotation was using the given
"hop" argument as the lock subclass key.  Although the idea itself
works, it may trigger a kernel warning like:
  BUG: looking up invalid subclass: 8
  ....
since the lockdep has a smaller number of subclasses (8) than we
currently allow for the hops there (10).

The current definition is merely a sanity check for avoiding the too
deep delivery paths, and the 8 hops are already enough.  So, as a
quick fix, just follow the max hops as same as the max lockdep
subclasses.

Fixes: 1f20f9ff57ca ("ALSA: seq: Fix nested rwsem annotation for lockdep splat")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ALSA: timer: Limit max instances per timer 2018-01-01T20:51:02+00:00 Takashi Iwai tiwai@suse.de 2017-11-05T09:07:43+00:00 57a70fe807328d99a7e483592b883b2e8abaca13 commit 9b7d869ee5a77ed4a462372bb89af622e705bfb8 upstream. Currently we allow unlimited number of timer instances, and it may bring the system hogging way too much CPU when too many timer instances are opened and processed concurrently. This may end up with a soft-lockup report as triggered by syzkaller, especially when hrtimer backend is deployed. Since such insane number of instances aren't demanded by the normal use case of ALSA sequencer and it merely opens a risk only for abuse, this patch introduces the upper limit for the number of instances per timer backend. As default, it's set to 1000, but for the fine-grained timer like hrtimer, it's set to 100. Reported-by: syzbot Tested-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 9b7d869ee5a77ed4a462372bb89af622e705bfb8 upstream.

Currently we allow unlimited number of timer instances, and it may
bring the system hogging way too much CPU when too many timer
instances are opened and processed concurrently.  This may end up with
a soft-lockup report as triggered by syzkaller, especially when
hrtimer backend is deployed.

Since such insane number of instances aren't demanded by the normal
use case of ALSA sequencer and it merely  opens a risk only for abuse,
this patch introduces the upper limit for the number of instances per
timer backend.  As default, it's set to 1000, but for the fine-grained
timer like hrtimer, it's set to 100.

Reported-by: syzbot
Tested-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
tcp: fix tcp_mtu_probe() vs highest_sack 2018-01-01T20:51:00+00:00 Eric Dumazet edumazet@google.com 2017-10-31T06:08:20+00:00 7451eb5f46e23df1f8e280af3a820cf55710137b commit 2b7cda9c35d3b940eb9ce74b30bbd5eb30db493d upstream. Based on SNMP values provided by Roman, Yuchung made the observation that some crashes in tcp_sacktag_walk() might be caused by MTU probing. Looking at tcp_mtu_probe(), I found that when a new skb was placed in front of the write queue, we were not updating tcp highest sack. If one skb is freed because all its content was copied to the new skb (for MTU probing), then tp->highest_sack could point to a now freed skb. Bad things would then happen, including infinite loops. This patch renames tcp_highest_sack_combine() and uses it from tcp_mtu_probe() to fix the bug. Note that I also removed one test against tp->sacked_out, since we want to replace tp->highest_sack regardless of whatever condition, since keeping a stale pointer to freed skb is a recipe for disaster. Fixes: a47e5a988a57 ("[TCP]: Convert highest_sack to sk_buff to allow direct access") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> Reported-by: Roman Gushchin <guro@fb.com> Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 2b7cda9c35d3b940eb9ce74b30bbd5eb30db493d upstream.

Based on SNMP values provided by Roman, Yuchung made the observation
that some crashes in tcp_sacktag_walk() might be caused by MTU probing.

Looking at tcp_mtu_probe(), I found that when a new skb was placed
in front of the write queue, we were not updating tcp highest sack.

If one skb is freed because all its content was copied to the new skb
(for MTU probing), then tp->highest_sack could point to a now freed skb.

Bad things would then happen, including infinite loops.

This patch renames tcp_highest_sack_combine() and uses it
from tcp_mtu_probe() to fix the bug.

Note that I also removed one test against tp->sacked_out,
since we want to replace tp->highest_sack regardless of whatever
condition, since keeping a stale pointer to freed skb is a recipe
for disaster.

Fixes: a47e5a988a57 ("[TCP]: Convert highest_sack to sk_buff to allow direct access")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Reported-by: Roman Gushchin <guro@fb.com>
Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ALSA: seq: Fix copy_from_user() call inside lock 2018-01-01T20:50:56+00:00 Takashi Iwai tiwai@suse.de 2017-10-09T08:02:56+00:00 3bad09df43577f98cbf45a6aecf0d8b061ee4325 commit 5803b023881857db32ffefa0d269c90280a67ee0 upstream. The event handler in the virmidi sequencer code takes a read-lock for the linked list traverse, while it's calling snd_seq_dump_var_event() in the loop. The latter function may expand the user-space data depending on the event type. It eventually invokes copy_from_user(), which might be a potential dead-lock. The sequencer core guarantees that the user-space data is passed only with atomic=0 argument, but snd_virmidi_dev_receive_event() ignores it and always takes read-lock(). For avoiding the problem above, this patch introduces rwsem for non-atomic case, while keeping rwlock for atomic case. Also while we're at it: the superfluous irq flags is dropped in snd_virmidi_input_open(). Reported-by: Jia-Ju Bai <baijiaju1990@163.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 5803b023881857db32ffefa0d269c90280a67ee0 upstream.

The event handler in the virmidi sequencer code takes a read-lock for
the linked list traverse, while it's calling snd_seq_dump_var_event()
in the loop.  The latter function may expand the user-space data
depending on the event type.  It eventually invokes copy_from_user(),
which might be a potential dead-lock.

The sequencer core guarantees that the user-space data is passed only
with atomic=0 argument, but snd_virmidi_dev_receive_event() ignores it
and always takes read-lock().  For avoiding the problem above, this
patch introduces rwsem for non-atomic case, while keeping rwlock for
atomic case.

Also while we're at it: the superfluous irq flags is dropped in
snd_virmidi_input_open().

Reported-by: Jia-Ju Bai <baijiaju1990@163.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
scsi: sd: Implement blacklist option for WRITE SAME w/ UNMAP 2018-01-01T20:50:55+00:00 Martin K. Petersen martin.petersen@oracle.com 2017-09-28T01:35:12+00:00 a75a0b71bc065dc42701e7708a8e6b368ea01864 commit 28a0bc4120d38a394499382ba21d6965a67a3703 upstream. SBC-4 states: "A MAXIMUM UNMAP LBA COUNT field set to a non-zero value indicates the maximum number of LBAs that may be unmapped by an UNMAP command" "A MAXIMUM WRITE SAME LENGTH field set to a non-zero value indicates the maximum number of contiguous logical blocks that the device server allows to be unmapped or written in a single WRITE SAME command." Despite the spec being clear on the topic, some devices incorrectly expect WRITE SAME commands with the UNMAP bit set to be limited to the value reported in MAXIMUM UNMAP LBA COUNT in the Block Limits VPD. Implement a blacklist option that can be used to accommodate devices with this behavior. Reported-by: Bill Kuzeja <William.Kuzeja@stratus.com> Reported-by: Ewan D. Milne <emilne@redhat.com> Reviewed-by: Ewan D. Milne <emilne@redhat.com> Tested-by: Laurence Oberman <loberman@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> [bwh: Backported to 3.2: - Keep using literals for SD_MAX_WS{16,10}_BLOCKS - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 28a0bc4120d38a394499382ba21d6965a67a3703 upstream.

SBC-4 states:

  "A MAXIMUM UNMAP LBA COUNT field set to a non-zero value indicates the
   maximum number of LBAs that may be unmapped by an UNMAP command"

  "A MAXIMUM WRITE SAME LENGTH field set to a non-zero value indicates
   the maximum number of contiguous logical blocks that the device server
   allows to be unmapped or written in a single WRITE SAME command."

Despite the spec being clear on the topic, some devices incorrectly
expect WRITE SAME commands with the UNMAP bit set to be limited to the
value reported in MAXIMUM UNMAP LBA COUNT in the Block Limits VPD.

Implement a blacklist option that can be used to accommodate devices
with this behavior.

Reported-by: Bill Kuzeja <William.Kuzeja@stratus.com>
Reported-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
[bwh: Backported to 3.2:
 - Keep using literals for SD_MAX_WS{16,10}_BLOCKS
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
KEYS: prevent creating a different user's keyrings 2018-01-01T20:50:52+00:00 Eric Biggers ebiggers@google.com 2017-09-18T18:37:03+00:00 a0ff43031db9d248f659a5db3a819f5498203775 commit 237bbd29f7a049d310d907f4b2716a7feef9abf3 upstream. It was possible for an unprivileged user to create the user and user session keyrings for another user. For example: sudo -u '#3000' sh -c 'keyctl add keyring _uid.4000 "" @u keyctl add keyring _uid_ses.4000 "" @u sleep 15' & sleep 1 sudo -u '#4000' keyctl describe @u sudo -u '#4000' keyctl describe @us This is problematic because these "fake" keyrings won't have the right permissions. In particular, the user who created them first will own them and will have full access to them via the possessor permissions, which can be used to compromise the security of a user's keys: -4: alswrv-----v------------ 3000 0 keyring: _uid.4000 -5: alswrv-----v------------ 3000 0 keyring: _uid_ses.4000 Fix it by marking user and user session keyrings with a flag KEY_FLAG_UID_KEYRING. Then, when searching for a user or user session keyring by name, skip all keyrings that don't have the flag set. Fixes: 69664cf16af4 ("keys: don't generate user and user session keyrings unless they're accessed") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 237bbd29f7a049d310d907f4b2716a7feef9abf3 upstream.

It was possible for an unprivileged user to create the user and user
session keyrings for another user.  For example:

    sudo -u '#3000' sh -c 'keyctl add keyring _uid.4000 "" @u
                           keyctl add keyring _uid_ses.4000 "" @u
                           sleep 15' &
    sleep 1
    sudo -u '#4000' keyctl describe @u
    sudo -u '#4000' keyctl describe @us

This is problematic because these "fake" keyrings won't have the right
permissions.  In particular, the user who created them first will own
them and will have full access to them via the possessor permissions,
which can be used to compromise the security of a user's keys:

    -4: alswrv-----v------------  3000     0 keyring: _uid.4000
    -5: alswrv-----v------------  3000     0 keyring: _uid_ses.4000

Fix it by marking user and user session keyrings with a flag
KEY_FLAG_UID_KEYRING.  Then, when searching for a user or user session
keyring by name, skip all keyrings that don't have the flag set.

Fixes: 69664cf16af4 ("keys: don't generate user and user session keyrings unless they're accessed")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Input: uinput - avoid FF flush when destroying device 2018-01-01T20:50:50+00:00 Dmitry Torokhov dmitry.torokhov@gmail.com 2017-09-02T00:13:43+00:00 3eee55582f4b23d2579286c5ba61d82828bd655f commit e8b95728f724797f958912fd9b765a695595d3a6 upstream. Normally, when input device supporting force feedback effects is being destroyed, we try to "flush" currently playing effects, so that the physical device does not continue vibrating (or executing other effects). Unfortunately this does not work well for uinput as flushing of the effects deadlocks with the destroy action: - if device is being destroyed because the file descriptor is being closed, then there is noone to even service FF requests; - if device is being destroyed because userspace sent UI_DEV_DESTROY, while theoretically it could be possible to service FF requests, userspace is unlikely to do so (they'd need to make sure FF handling happens on a separate thread) even if kernel solves the issue with FF ioctls deadlocking with UI_DEV_DESTROY ioctl on udev->mutex. To avoid lockups like the one below, let's install a custom input device flush handler, and avoid trying to flush force feedback effects when we destroying the device, and instead rely on uinput to shut off the device properly. NMI watchdog: Watchdog detected hard LOCKUP on cpu 3 ... <<EOE>> [<ffffffff817a0307>] _raw_spin_lock_irqsave+0x37/0x40 [<ffffffff810e633d>] complete+0x1d/0x50 [<ffffffffa00ba08c>] uinput_request_done+0x3c/0x40 [uinput] [<ffffffffa00ba587>] uinput_request_submit.part.7+0x47/0xb0 [uinput] [<ffffffffa00bb62b>] uinput_dev_erase_effect+0x5b/0x76 [uinput] [<ffffffff815d91ad>] erase_effect+0xad/0xf0 [<ffffffff815d929d>] flush_effects+0x4d/0x90 [<ffffffff815d4cc0>] input_flush_device+0x40/0x60 [<ffffffff815daf1c>] evdev_cleanup+0xac/0xc0 [<ffffffff815daf5b>] evdev_disconnect+0x2b/0x60 [<ffffffff815d74ac>] __input_unregister_device+0xac/0x150 [<ffffffff815d75f7>] input_unregister_device+0x47/0x70 [<ffffffffa00bac45>] uinput_destroy_device+0xb5/0xc0 [uinput] [<ffffffffa00bb2de>] uinput_ioctl_handler.isra.9+0x65e/0x740 [uinput] [<ffffffff811231ab>] ? do_futex+0x12b/0xad0 [<ffffffffa00bb3f8>] uinput_ioctl+0x18/0x20 [uinput] [<ffffffff81241248>] do_vfs_ioctl+0x298/0x480 [<ffffffff81337553>] ? security_file_ioctl+0x43/0x60 [<ffffffff812414a9>] SyS_ioctl+0x79/0x90 [<ffffffff817a04ee>] entry_SYSCALL_64_fastpath+0x12/0x71 Reported-by: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com> Reported-by: Clément VUCHENER <clement.vuchener@gmail.com> Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=193741 Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit e8b95728f724797f958912fd9b765a695595d3a6 upstream.

Normally, when input device supporting force feedback effects is being
destroyed, we try to "flush" currently playing effects, so that the
physical device does not continue vibrating (or executing other effects).
Unfortunately this does not work well for uinput as flushing of the effects
deadlocks with the destroy action:

- if device is being destroyed because the file descriptor is being closed,
  then there is noone to even service FF requests;

- if device is being destroyed because userspace sent UI_DEV_DESTROY,
  while theoretically it could be possible to service FF requests,
  userspace is unlikely to do so (they'd need to make sure FF handling
  happens on a separate thread) even if kernel solves the issue with FF
  ioctls deadlocking with UI_DEV_DESTROY ioctl on udev->mutex.

To avoid lockups like the one below, let's install a custom input device
flush handler, and avoid trying to flush force feedback effects when we
destroying the device, and instead rely on uinput to shut off the device
properly.

NMI watchdog: Watchdog detected hard LOCKUP on cpu 3
...
 <<EOE>>  [<ffffffff817a0307>] _raw_spin_lock_irqsave+0x37/0x40
 [<ffffffff810e633d>] complete+0x1d/0x50
 [<ffffffffa00ba08c>] uinput_request_done+0x3c/0x40 [uinput]
 [<ffffffffa00ba587>] uinput_request_submit.part.7+0x47/0xb0 [uinput]
 [<ffffffffa00bb62b>] uinput_dev_erase_effect+0x5b/0x76 [uinput]
 [<ffffffff815d91ad>] erase_effect+0xad/0xf0
 [<ffffffff815d929d>] flush_effects+0x4d/0x90
 [<ffffffff815d4cc0>] input_flush_device+0x40/0x60
 [<ffffffff815daf1c>] evdev_cleanup+0xac/0xc0
 [<ffffffff815daf5b>] evdev_disconnect+0x2b/0x60
 [<ffffffff815d74ac>] __input_unregister_device+0xac/0x150
 [<ffffffff815d75f7>] input_unregister_device+0x47/0x70
 [<ffffffffa00bac45>] uinput_destroy_device+0xb5/0xc0 [uinput]
 [<ffffffffa00bb2de>] uinput_ioctl_handler.isra.9+0x65e/0x740 [uinput]
 [<ffffffff811231ab>] ? do_futex+0x12b/0xad0
 [<ffffffffa00bb3f8>] uinput_ioctl+0x18/0x20 [uinput]
 [<ffffffff81241248>] do_vfs_ioctl+0x298/0x480
 [<ffffffff81337553>] ? security_file_ioctl+0x43/0x60
 [<ffffffff812414a9>] SyS_ioctl+0x79/0x90
 [<ffffffff817a04ee>] entry_SYSCALL_64_fastpath+0x12/0x71

Reported-by: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
Reported-by: Clément VUCHENER <clement.vuchener@gmail.com>
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=193741
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>