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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Hao Sun <sunhao.th@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Stanislav Fomichev <sdf@google.com>,
	Sasha Levin <sashal@kernel.org>,
	ast@kernel.org, andrii@kernel.org, song@kernel.org,
	rostedt@goodmis.org, mhiramat@kernel.org, bpf@vger.kernel.org
Subject: [PATCH AUTOSEL 6.1 06/35] bpf: Skip task with pid=1 in send_signal_common()
Date: Tue, 24 Jan 2023 08:41:02 -0500	[thread overview]
Message-ID: <20230124134131.637036-6-sashal@kernel.org> (raw)
In-Reply-To: <20230124134131.637036-1-sashal@kernel.org>

From: Hao Sun <sunhao.th@gmail.com>

[ Upstream commit a3d81bc1eaef48e34dd0b9b48eefed9e02a06451 ]

The following kernel panic can be triggered when a task with pid=1 attaches
a prog that attempts to send killing signal to itself, also see [1] for more
details:

  Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
  CPU: 3 PID: 1 Comm: systemd Not tainted 6.1.0-09652-g59fe41b5255f #148
  Call Trace:
  <TASK>
  __dump_stack lib/dump_stack.c:88 [inline]
  dump_stack_lvl+0x100/0x178 lib/dump_stack.c:106
  panic+0x2c4/0x60f kernel/panic.c:275
  do_exit.cold+0x63/0xe4 kernel/exit.c:789
  do_group_exit+0xd4/0x2a0 kernel/exit.c:950
  get_signal+0x2460/0x2600 kernel/signal.c:2858
  arch_do_signal_or_restart+0x78/0x5d0 arch/x86/kernel/signal.c:306
  exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
  exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203
  __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
  syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296
  do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86
  entry_SYSCALL_64_after_hwframe+0x63/0xcd

So skip task with pid=1 in bpf_send_signal_common() to avoid the panic.

  [1] https://lore.kernel.org/bpf/20221222043507.33037-1-sunhao.th@gmail.com

Signed-off-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230106084838.12690-1-sunhao.th@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/trace/bpf_trace.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 1ed08967fb97..eb8c117cc8b6 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -847,6 +847,9 @@ static int bpf_send_signal_common(u32 sig, enum pid_type type)
 		return -EPERM;
 	if (unlikely(!nmi_uaccess_okay()))
 		return -EPERM;
+	/* Task should not be pid=1 to avoid kernel panic. */
+	if (unlikely(is_global_init(current)))
+		return -EPERM;
 
 	if (irqs_disabled()) {
 		/* Do an early check on signal validity. Otherwise,
-- 
2.39.0


  parent reply	other threads:[~2023-01-24 13:42 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-24 13:40 [PATCH AUTOSEL 6.1 01/35] ARM: dts: imx: Fix pca9547 i2c-mux node name Sasha Levin
2023-01-24 13:40 ` [PATCH AUTOSEL 6.1 02/35] ARM: dts: vf610: Fix pca9548 i2c-mux node names Sasha Levin
2023-01-24 13:40 ` [PATCH AUTOSEL 6.1 03/35] arm64: dts: freescale: Fix pca954x " Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 04/35] arm64: dts: imx8mq-thor96: fix no-mmc property for SDHCI Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 05/35] firmware: arm_scmi: Clear stale xfer->hdr.status Sasha Levin
2023-01-24 13:41 ` Sasha Levin [this message]
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 07/35] erofs/zmap.c: Fix incorrect offset calculation Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 08/35] mac80211: Fix MLO address translation for multiple bss case Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 09/35] arm64: dts: msm8994-angler: fix the memory map Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 10/35] ARM: omap1: fix building gpio15xx Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 11/35] init/Kconfig: fix LOCALVERSION_AUTO help text Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 12/35] kselftest: Fix error message for unconfigured LLVM builds Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 13/35] erofs: clean up parsing of fscache related options Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 14/35] btrfs: factor out scratching of one regular super block Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 15/35] btrfs: stop using write_one_page in btrfs_scratch_superblock Sasha Levin
2023-01-24 16:57   ` David Sterba
2023-02-01 15:21     ` Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 16/35] blk-cgroup: fix missing pd_online_fn() while activating policy Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 17/35] LoongArch: Get frame info in unwind_start() when regs is not available Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 18/35] ACPI: video: Add backlight=native DMI quirk for Acer Aspire 4810T Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 19/35] block: fix hctx checks for batch allocation Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 20/35] s390: workaround invalid gcc-11 out of bounds read warning Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 21/35] HID: uclogic: Add support for XP-PEN Deco 01 V2 Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 22/35] HID: playstation: sanity check DualSense calibration data Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 23/35] dmaengine: imx-sdma: Fix a possible memory leak in sdma_transfer_init Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 24/35] gpiolib: acpi: Allow ignoring wake capability on pins that aren't in _AEI Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 25/35] cifs: fix return of uninitialized rc in dfs_cache_update_tgthint() Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 26/35] nvme-apple: only reset the controller when RTKit is running Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 27/35] octeontx2-af: recover CPT engine when it gets fault Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 28/35] octeontx2-af: add mbox for CPT LF reset Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 29/35] octeontx2-af: modify FLR sequence for CPT Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 30/35] octeontx2-af: optimize cpt pf identification Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 31/35] octeontx2-af: restore rxc conf after teardown sequence Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 32/35] octeontx2-af: update cpt lf alloc mailbox Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 33/35] octeontx2-af: add mbox to return CPT_AF_FLT_INT info Sasha Levin
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 34/35] prlimit: do_prlimit needs to have a speculation check Sasha Levin
2023-01-24 15:28   ` Greg Kroah-Hartman
2023-01-24 13:41 ` [PATCH AUTOSEL 6.1 35/35] ext4: deal with legacy signed xattr name hash values Sasha Levin
2023-01-24 16:50   ` Linus Torvalds
2023-01-24 17:23     ` Linus Torvalds
2023-01-25 16:01       ` Theodore Ts'o
2023-01-26 14:12         ` Sasha Levin

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