From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-179.mta0.migadu.com (out-179.mta0.migadu.com [91.218.175.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CA530413799 for ; Wed, 5 Aug 2026 15:08:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785942530; cv=none; b=Vnc0TltYDQYZmO38jnGk5h1rBJP1QBEeNxILtn8LRTrtllDq0TdBqbVfriDq9jxUkPhJAQMjYh37ClhIftCjMgb72Zz/8/D6R6A7B3fd3RhZdYJAczeLGEBZRVk4SeX/MW4cFciK+yci0JFgBWnmNuqeJkfkPDHfckKEXygm0NI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785942530; c=relaxed/simple; bh=IQfLQdClZMPZWBWuUP7MTmaessUwzjFwaPvlNJSzg54=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=sZilzGqwUmhmqF3vs8MToV+I0jVHakIfGID9j8wG9L24wpBUXhdVlf6SL65k1PbzfMG8he0hfni0zwT4xIms+xYlC1gTBe2MT8RVDlzDEbWkNcesyzhO10q9dVm5hwtAPDT84io7KvRs9gr6JDuAnV0aS1N9aWOiIhp6b/oppo8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=aJywKU/R; arc=none smtp.client-ip=91.218.175.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="aJywKU/R" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1785942513; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=ARFtpgOT454Lo9ITBNeyHQKUU++b3Gc1sMwAfKESuoA=; b=aJywKU/RoubdNLur0gS5E0MRYqQUCEtlr47i7RrioDXJ8ry6AW4GzACLap8lC9o3XTj5mv XgVOjhZul1HKmuJO5MaRB0y5tRTUWKN1FQKZoLyY3f4/ilw53jr+PNZig2uVEC5ivWsk5I ZP3lpA3ypwZpA1wq8KIUnslB6hKzSA4= From: Leon Hwang To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , Shuah Khan , Sechang Lim , Varun R Mallya , Leon Hwang , Viktor Malik , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH bpf-next v4 0/2] bpf: Fix sleepable check for tracing/lsm prog Date: Wed, 5 Aug 2026 23:08:08 +0800 Message-ID: <20260805150810.34907-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT When CONFIG_FUNCTION_ERROR_INJECTION is disabled, a sleepable tracing prog is allowed to attach to '__x64_'-alike prefix symbols. It is because the verifier does not verify whether the symbol is a kernel function or a bpf prog. That said, a sleepable tracing prog is allowed to attach to a bpf prog target whose name has '__x64_'-alike prefix. For example, a sleepable fentry prog attaches to a '__x64_sys_nop' XDP prog, and copies buffer from a user pointer with bpf_copy_from_user() helper. After attaching the XDP prog to lo interface, the kernel BUG could be triggered by 'ping -c 1 -W 1 127.0.0.1': [ 3.460756] BUG: sleeping function called from invalid context at kernel/bpf/trampoline.c:1324 Similar issue could be applied to lsm prog, when the prog->aux->attach_btf_id is in the LSM allowing list but the attach_btf is a malicious bpf prog's btf. Fix it by disallowing sleepable tracing/lsm prog always when its target btf is not kernel's btf. Changes: v3 -> v4: * Add Fixes tag for sleepable LSM case. * Move btf check outside of 'switch (prog->type)'. (per Andrii) * v3: https://lore.kernel.org/bpf/20260804145710.43062-1-leon.hwang@linux.dev/ v2 -> v3: * Use btf_is_kernel() instead of passing 'tgt_prog'. (per Andrii) * v2: https://lore.kernel.org/bpf/20260725132624.78373-1-leon.hwang@linux.dev/ v1 -> v2: * Drop redundant 'prog->sleepable' check. (per Viktor) * Collect Acked-by from Viktor, Thanks. * v1: https://lore.kernel.org/bpf/20260724141422.10463-1-leon.hwang@linux.dev/ Leon Hwang (2): bpf: Fix sleepable check for tracing/lsm prog selftests/bpf: Verify rejection of sleepable tracing prog kernel/bpf/verifier.c | 3 + .../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 57 +++++++++++++++++++ .../selftests/bpf/progs/fentry_sleepable.c | 18 ++++++ tools/testing/selftests/bpf/progs/xdp_dummy.c | 6 ++ 4 files changed, 84 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/fentry_sleepable.c -- 2.55.0