1. 10 Sep, 2018 34 commits
  2. 06 Sep, 2018 6 commits
    • Greg Kroah-Hartman's avatar
    • Tetsuo Handa's avatar
      net/nfc: Avoid stalls when nfc_alloc_send_skb() returned NULL. · d6b6570e
      Tetsuo Handa authored
      BugLink: https://bugs.launchpad.net/bugs/1790884
      
      commit 3bc53be9 upstream.
      
      syzbot is reporting stalls at nfc_llcp_send_ui_frame() [1]. This is
      because nfc_llcp_send_ui_frame() is retrying the loop without any delay
      when nonblocking nfc_alloc_send_skb() returned NULL.
      
      Since there is no need to use MSG_DONTWAIT if we retry until
      sock_alloc_send_pskb() succeeds, let's use blocking call.
      Also, in case an unexpected error occurred, let's break the loop
      if blocking nfc_alloc_send_skb() failed.
      
      [1] https://syzkaller.appspot.com/bug?id=4a131cc571c3733e0eff6bc673f4e36ae48f19c6Signed-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
      Reported-by: default avatarsyzbot <syzbot+d29d18215e477cfbfbdd@syzkaller.appspotmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarStefan Bader <stefan.bader@canonical.com>
      Signed-off-by: default avatarKleber Sacilotto de Souza <kleber.souza@canonical.com>
      d6b6570e
    • Santosh Shilimkar's avatar
      rds: avoid unenecessary cong_update in loop transport · 6ac4d332
      Santosh Shilimkar authored
      BugLink: https://bugs.launchpad.net/bugs/1790884
      
      commit f1693c63 upstream.
      
      Loop transport which is self loopback, remote port congestion
      update isn't relevant. Infact the xmit path already ignores it.
      Receive path needs to do the same.
      
      Reported-by: syzbot+4c20b3866171ce8441d2@syzkaller.appspotmail.com
      Reviewed-by: default avatarSowmini Varadhan <sowmini.varadhan@oracle.com>
      Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@oracle.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarStefan Bader <stefan.bader@canonical.com>
      Signed-off-by: default avatarKleber Sacilotto de Souza <kleber.souza@canonical.com>
      6ac4d332
    • Eric Biggers's avatar
      KEYS: DNS: fix parsing multiple options · 9c040fa9
      Eric Biggers authored
      BugLink: https://bugs.launchpad.net/bugs/1790884
      
      commit c604cb76 upstream.
      
      My recent fix for dns_resolver_preparse() printing very long strings was
      incomplete, as shown by syzbot which still managed to hit the
      WARN_ONCE() in set_precision() by adding a crafted "dns_resolver" key:
      
          precision 50001 too large
          WARNING: CPU: 7 PID: 864 at lib/vsprintf.c:2164 vsnprintf+0x48a/0x5a0
      
      The bug this time isn't just a printing bug, but also a logical error
      when multiple options ("#"-separated strings) are given in the key
      payload.  Specifically, when separating an option string into name and
      value, if there is no value then the name is incorrectly considered to
      end at the end of the key payload, rather than the end of the current
      option.  This bypasses validation of the option length, and also means
      that specifying multiple options is broken -- which presumably has gone
      unnoticed as there is currently only one valid option anyway.
      
      A similar problem also applied to option values, as the kstrtoul() when
      parsing the "dnserror" option will read past the end of the current
      option and into the next option.
      
      Fix these bugs by correctly computing the length of the option name and
      by copying the option value, null-terminated, into a temporary buffer.
      
      Reproducer for the WARN_ONCE() that syzbot hit:
      
          perl -e 'print "#A#", "\0" x 50000' | keyctl padd dns_resolver desc @s
      
      Reproducer for "dnserror" option being parsed incorrectly (expected
      behavior is to fail when seeing the unknown option "foo", actual
      behavior was to read the dnserror value as "1#foo" and fail there):
      
          perl -e 'print "#dnserror=1#foo\0"' | keyctl padd dns_resolver desc @s
      Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
      Fixes: 4a2d7892 ("DNS: If the DNS server returns an error, allow that to be cached [ver #2]")
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarStefan Bader <stefan.bader@canonical.com>
      Signed-off-by: default avatarKleber Sacilotto de Souza <kleber.souza@canonical.com>
      9c040fa9
    • Florian Westphal's avatar
      netfilter: ebtables: reject non-bridge targets · 27370c84
      Florian Westphal authored
      BugLink: https://bugs.launchpad.net/bugs/1790884
      
      commit 11ff7288 upstream.
      
      the ebtables evaluation loop expects targets to return
      positive values (jumps), or negative values (absolute verdicts).
      
      This is completely different from what xtables does.
      In xtables, targets are expected to return the standard netfilter
      verdicts, i.e. NF_DROP, NF_ACCEPT, etc.
      
      ebtables will consider these as jumps.
      
      Therefore reject any target found due to unspec fallback.
      v2: also reject watchers.  ebtables ignores their return value, so
      a target that assumes skb ownership (and returns NF_STOLEN) causes
      use-after-free.
      
      The only watchers in the 'ebtables' front-end are log and nflog;
      both have AF_BRIDGE specific wrappers on kernel side.
      
      Reported-by: syzbot+2b43f681169a2a0d306a@syzkaller.appspotmail.com
      Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
      Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarStefan Bader <stefan.bader@canonical.com>
      Signed-off-by: default avatarKleber Sacilotto de Souza <kleber.souza@canonical.com>
      27370c84
    • Paul Burton's avatar
      MIPS: Use async IPIs for arch_trigger_cpumask_backtrace() · 0fa595a6
      Paul Burton authored
      BugLink: https://bugs.launchpad.net/bugs/1790884
      
      commit b63e132b upstream.
      
      The current MIPS implementation of arch_trigger_cpumask_backtrace() is
      broken because it attempts to use synchronous IPIs despite the fact that
      it may be run with interrupts disabled.
      
      This means that when arch_trigger_cpumask_backtrace() is invoked, for
      example by the RCU CPU stall watchdog, we may:
      
        - Deadlock due to use of synchronous IPIs with interrupts disabled,
          causing the CPU that's attempting to generate the backtrace output
          to hang itself.
      
        - Not succeed in generating the desired output from remote CPUs.
      
        - Produce warnings about this from smp_call_function_many(), for
          example:
      
          [42760.526910] INFO: rcu_sched detected stalls on CPUs/tasks:
          [42760.535755]  0-...!: (1 GPs behind) idle=ade/140000000000000/0 softirq=526944/526945 fqs=0
          [42760.547874]  1-...!: (0 ticks this GP) idle=e4a/140000000000000/0 softirq=547885/547885 fqs=0
          [42760.559869]  (detected by 2, t=2162 jiffies, g=266689, c=266688, q=33)
          [42760.568927] ------------[ cut here ]------------
          [42760.576146] WARNING: CPU: 2 PID: 1216 at kernel/smp.c:416 smp_call_function_many+0x88/0x20c
          [42760.587839] Modules linked in:
          [42760.593152] CPU: 2 PID: 1216 Comm: sh Not tainted 4.15.4-00373-gee058bb4d0c2 #2
          [42760.603767] Stack : 8e09bd20 8e09bd20 8e09bd20 fffffff0 00000007 00000006 00000000 8e09bca8
          [42760.616937]         95b2b379 95b2b379 807a0080 00000007 81944518 0000018a 00000032 00000000
          [42760.630095]         00000000 00000030 80000000 00000000 806eca74 00000009 8017e2b8 000001a0
          [42760.643169]         00000000 00000002 00000000 8e09baa4 00000008 808b8008 86d69080 8e09bca0
          [42760.656282]         8e09ad50 805e20aa 00000000 00000000 00000000 8017e2b8 00000009 801070ca
          [42760.669424]         ...
          [42760.673919] Call Trace:
          [42760.678672] [<27fde568>] show_stack+0x70/0xf0
          [42760.685417] [<84751641>] dump_stack+0xaa/0xd0
          [42760.692188] [<699d671c>] __warn+0x80/0x92
          [42760.698549] [<68915d41>] warn_slowpath_null+0x28/0x36
          [42760.705912] [<f7c76c1c>] smp_call_function_many+0x88/0x20c
          [42760.713696] [<6bbdfc2a>] arch_trigger_cpumask_backtrace+0x30/0x4a
          [42760.722216] [<f845bd33>] rcu_dump_cpu_stacks+0x6a/0x98
          [42760.729580] [<796e7629>] rcu_check_callbacks+0x672/0x6ac
          [42760.737476] [<059b3b43>] update_process_times+0x18/0x34
          [42760.744981] [<6eb94941>] tick_sched_handle.isra.5+0x26/0x38
          [42760.752793] [<478d3d70>] tick_sched_timer+0x1c/0x50
          [42760.759882] [<e56ea39f>] __hrtimer_run_queues+0xc6/0x226
          [42760.767418] [<e88bbcae>] hrtimer_interrupt+0x88/0x19a
          [42760.775031] [<6765a19e>] gic_compare_interrupt+0x2e/0x3a
          [42760.782761] [<0558bf5f>] handle_percpu_devid_irq+0x78/0x168
          [42760.790795] [<90c11ba2>] generic_handle_irq+0x1e/0x2c
          [42760.798117] [<1b6d462c>] gic_handle_local_int+0x38/0x86
          [42760.805545] [<b2ada1c7>] gic_irq_dispatch+0xa/0x14
          [42760.812534] [<90c11ba2>] generic_handle_irq+0x1e/0x2c
          [42760.820086] [<c7521934>] do_IRQ+0x16/0x20
          [42760.826274] [<9aef3ce6>] plat_irq_dispatch+0x62/0x94
          [42760.833458] [<6a94b53c>] except_vec_vi_end+0x70/0x78
          [42760.840655] [<22284043>] smp_call_function_many+0x1ba/0x20c
          [42760.848501] [<54022b58>] smp_call_function+0x1e/0x2c
          [42760.855693] [<ab9fc705>] flush_tlb_mm+0x2a/0x98
          [42760.862730] [<0844cdd0>] tlb_flush_mmu+0x1c/0x44
          [42760.869628] [<cb259b74>] arch_tlb_finish_mmu+0x26/0x3e
          [42760.877021] [<1aeaaf74>] tlb_finish_mmu+0x18/0x66
          [42760.883907] [<b3fce717>] exit_mmap+0x76/0xea
          [42760.890428] [<c4c8a2f6>] mmput+0x80/0x11a
          [42760.896632] [<a41a08f4>] do_exit+0x1f4/0x80c
          [42760.903158] [<ee01cef6>] do_group_exit+0x20/0x7e
          [42760.909990] [<13fa8d54>] __wake_up_parent+0x0/0x1e
          [42760.917045] [<46cf89d0>] smp_call_function_many+0x1a2/0x20c
          [42760.924893] [<8c21a93b>] syscall_common+0x14/0x1c
          [42760.931765] ---[ end trace 02aa09da9dc52a60 ]---
          [42760.938342] ------------[ cut here ]------------
          [42760.945311] WARNING: CPU: 2 PID: 1216 at kernel/smp.c:291 smp_call_function_single+0xee/0xf8
          ...
      
      This patch switches MIPS' arch_trigger_cpumask_backtrace() to use async
      IPIs & smp_call_function_single_async() in order to resolve this
      problem. We ensure use of the pre-allocated call_single_data_t
      structures is serialized by maintaining a cpumask indicating that
      they're busy, and refusing to attempt to send an IPI when a CPU's bit is
      set in this mask. This should only happen if a CPU hasn't responded to a
      previous backtrace IPI - ie. if it's hung - and we print a warning to
      the console in this case.
      
      I've marked this for stable branches as far back as v4.9, to which it
      applies cleanly. Strictly speaking the faulty MIPS implementation can be
      traced further back to commit 856839b7 ("MIPS: Add
      arch_trigger_all_cpu_backtrace() function") in v3.19, but kernel
      versions v3.19 through v4.8 will require further work to backport due to
      the rework performed in commit 9a01c3ed ("nmi_backtrace: add more
      trigger_*_cpu_backtrace() methods").
      Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
      Patchwork: https://patchwork.linux-mips.org/patch/19597/
      Cc: James Hogan <jhogan@kernel.org>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Huacai Chen <chenhc@lemote.com>
      Cc: linux-mips@linux-mips.org
      Cc: stable@vger.kernel.org # v4.9+
      Fixes: 856839b7 ("MIPS: Add arch_trigger_all_cpu_backtrace() function")
      Fixes: 9a01c3ed ("nmi_backtrace: add more trigger_*_cpu_backtrace() methods")
      [ Huacai: backported to 4.4: Restruction since generic NMI solution is unavailable ]
      Signed-off-by: default avatarHuacai Chen <chenhc@lemote.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarStefan Bader <stefan.bader@canonical.com>
      Signed-off-by: default avatarKleber Sacilotto de Souza <kleber.souza@canonical.com>
      0fa595a6