From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48QE/l+WTWe4k+EGd/8VW1TShJd4L/O+Zj4INyEITBxjrqFUdYb3DwEVP7IFbGxPreF58u3 ARC-Seal: i=1; a=rsa-sha256; t=1523981025; cv=none; d=google.com; s=arc-20160816; b=gtDWZL5ASiq/RjFHNUBMzSzld/Ux7Txl1Ifo9inzQM/4sBPh00+Ram3pCF2xZ2kZ8x xzWxFpNBtOS30dT3FWtvzif1Ra4e1OzIO2EYPG+cCnIyHG2+mJ1ewxVUn/QWYhSBhVFL 5SpdCfSZ085X5HYKoG2CeE8bDtWoW8JTZO/0wDizyqvuZCFQOfibSuKugHJ3QyWLmkPP S34EQRrESP3KgL7BKlZv5RpMzYKMEXg7em2s3aFxu14V57IqIFPpqpqhdWt33LY6tpqZ 7FMIS5tO5X/bnTonAqQwgMgN04wSvS7sKyA3waGXTn1fGOseYwjK9jO+52k/EO/epo0/ emVA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=wSPZ8YlAyHn1IA0P73EE0woDW+twnURJlEQY7H9blYQ=; b=Et8OF6xtrPylyYKK+inDpKcIwAbvA31PTrBmr4XHXUGK4JT+BMRqWUWXTA9YPEIocg ZzRfMvrNkfl94wKlclRLIzrHipUmxMf0q3LbsdKJt86LPrQafMryBwQ+NvhYF6uDbQSl ZYip8I16f91nLdCCLpQq7EUdxdYxwhzo3MGHSGQQ4tE9QA9thtT0w4YJ2cDaClFbISRR +4ib2uLZgLZsbosqNRVts+N1U//dCVfwQdguGPMjInahWradoxo4uFRxNb7fTLIKyfc6 HzjywfN7bdfiGattUOJfo+dAyukd2srXkzGn4r/HVnJJKjNDFMlt5GAZv65Oiq++AcFR cjBA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 46.44.180.42 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 46.44.180.42 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Prashant Bhole , Oleg Nesterov , "Peter Zijlstra (Intel)" , stable@kernel.org, Alexander Shishkin , Arnaldo Carvalho de Melo , Jiri Olsa , Linus Torvalds , Namhyung Kim , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.15 21/53] perf/core: Fix use-after-free in uprobe_perf_close() Date: Tue, 17 Apr 2018 17:58:46 +0200 Message-Id: <20180417155724.137859137@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180417155723.091120060@linuxfoundation.org> References: <20180417155723.091120060@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598009793844630333?= X-GMAIL-MSGID: =?utf-8?q?1598009927454216345?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Prashant Bhole commit 621b6d2ea297d0fb6030452c5bcd221f12165fcf upstream. A use-after-free bug was caught by KASAN while running usdt related code (BCC project. bcc/tests/python/test_usdt2.py): ================================================================== BUG: KASAN: use-after-free in uprobe_perf_close+0x222/0x3b0 Read of size 4 at addr ffff880384f9b4a4 by task test_usdt2.py/870 CPU: 4 PID: 870 Comm: test_usdt2.py Tainted: G W 4.16.0-next-20180409 #215 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0xc7/0x15b ? show_regs_print_info+0x5/0x5 ? printk+0x9c/0xc3 ? kmsg_dump_rewind_nolock+0x6e/0x6e ? uprobe_perf_close+0x222/0x3b0 print_address_description+0x83/0x3a0 ? uprobe_perf_close+0x222/0x3b0 kasan_report+0x1dd/0x460 ? uprobe_perf_close+0x222/0x3b0 uprobe_perf_close+0x222/0x3b0 ? probes_open+0x180/0x180 ? free_filters_list+0x290/0x290 trace_uprobe_register+0x1bb/0x500 ? perf_event_attach_bpf_prog+0x310/0x310 ? probe_event_disable+0x4e0/0x4e0 perf_uprobe_destroy+0x63/0xd0 _free_event+0x2bc/0xbd0 ? lockdep_rcu_suspicious+0x100/0x100 ? ring_buffer_attach+0x550/0x550 ? kvm_sched_clock_read+0x1a/0x30 ? perf_event_release_kernel+0x3e4/0xc00 ? __mutex_unlock_slowpath+0x12e/0x540 ? wait_for_completion+0x430/0x430 ? lock_downgrade+0x3c0/0x3c0 ? lock_release+0x980/0x980 ? do_raw_spin_trylock+0x118/0x150 ? do_raw_spin_unlock+0x121/0x210 ? do_raw_spin_trylock+0x150/0x150 perf_event_release_kernel+0x5d4/0xc00 ? put_event+0x30/0x30 ? fsnotify+0xd2d/0xea0 ? sched_clock_cpu+0x18/0x1a0 ? __fsnotify_update_child_dentry_flags.part.0+0x1b0/0x1b0 ? pvclock_clocksource_read+0x152/0x2b0 ? pvclock_read_flags+0x80/0x80 ? kvm_sched_clock_read+0x1a/0x30 ? sched_clock_cpu+0x18/0x1a0 ? pvclock_clocksource_read+0x152/0x2b0 ? locks_remove_file+0xec/0x470 ? pvclock_read_flags+0x80/0x80 ? fcntl_setlk+0x880/0x880 ? ima_file_free+0x8d/0x390 ? lockdep_rcu_suspicious+0x100/0x100 ? ima_file_check+0x110/0x110 ? fsnotify+0xea0/0xea0 ? kvm_sched_clock_read+0x1a/0x30 ? rcu_note_context_switch+0x600/0x600 perf_release+0x21/0x40 __fput+0x264/0x620 ? fput+0xf0/0xf0 ? do_raw_spin_unlock+0x121/0x210 ? do_raw_spin_trylock+0x150/0x150 ? SyS_fchdir+0x100/0x100 ? fsnotify+0xea0/0xea0 task_work_run+0x14b/0x1e0 ? task_work_cancel+0x1c0/0x1c0 ? copy_fd_bitmaps+0x150/0x150 ? vfs_read+0xe5/0x260 exit_to_usermode_loop+0x17b/0x1b0 ? trace_event_raw_event_sys_exit+0x1a0/0x1a0 do_syscall_64+0x3f6/0x490 ? syscall_return_slowpath+0x2c0/0x2c0 ? lockdep_sys_exit+0x1f/0xaa ? syscall_return_slowpath+0x1a3/0x2c0 ? lockdep_sys_exit+0x1f/0xaa ? prepare_exit_to_usermode+0x11c/0x1e0 ? enter_from_user_mode+0x30/0x30 random: crng init done ? __put_user_4+0x1c/0x30 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x7f41d95f9340 RSP: 002b:00007fffe71e4268 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 000000000000000d RCX: 00007f41d95f9340 RDX: 0000000000000000 RSI: 0000000000002401 RDI: 000000000000000d RBP: 0000000000000000 R08: 00007f41ca8ff700 R09: 00007f41d996dd1f R10: 00007fffe71e41e0 R11: 0000000000000246 R12: 00007fffe71e4330 R13: 0000000000000000 R14: fffffffffffffffc R15: 00007fffe71e4290 Allocated by task 870: kasan_kmalloc+0xa0/0xd0 kmem_cache_alloc_node+0x11a/0x430 copy_process.part.19+0x11a0/0x41c0 _do_fork+0x1be/0xa20 do_syscall_64+0x198/0x490 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Freed by task 0: __kasan_slab_free+0x12e/0x180 kmem_cache_free+0x102/0x4d0 free_task+0xfe/0x160 __put_task_struct+0x189/0x290 delayed_put_task_struct+0x119/0x250 rcu_process_callbacks+0xa6c/0x1b60 __do_softirq+0x238/0x7ae The buggy address belongs to the object at ffff880384f9b480 which belongs to the cache task_struct of size 12928 It occurs because task_struct is freed before perf_event which refers to the task and task flags are checked while teardown of the event. perf_event_alloc() assigns task_struct to hw.target of perf_event, but there is no reference counting for it. As a fix we get_task_struct() in perf_event_alloc() at above mentioned assignment and put_task_struct() in _free_event(). Signed-off-by: Prashant Bhole Reviewed-by: Oleg Nesterov Acked-by: Peter Zijlstra (Intel) Cc: Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 63b6da39bb38e8f1a1ef3180d32a39d6 ("perf: Fix perf_event_exit_task() race") Link: http://lkml.kernel.org/r/20180409100346.6416-1-bhole_prashant_q7@lab.ntt.co.jp Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/events/core.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4112,6 +4112,9 @@ static void _free_event(struct perf_even if (event->ctx) put_ctx(event->ctx); + if (event->hw.target) + put_task_struct(event->hw.target); + exclusive_event_destroy(event); module_put(event->pmu->module); @@ -9456,6 +9459,7 @@ perf_event_alloc(struct perf_event_attr * and we cannot use the ctx information because we need the * pmu before we get a ctx. */ + get_task_struct(task); event->hw.target = task; } @@ -9571,6 +9575,8 @@ err_ns: perf_detach_cgroup(event); if (event->ns) put_pid_ns(event->ns); + if (event->hw.target) + put_task_struct(event->hw.target); kfree(event); return ERR_PTR(err);