From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-186.mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (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 0D85442D753 for ; Wed, 5 Aug 2026 15:08:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.186 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785942527; cv=none; b=Fu7h+mK9AnetlB58AL9mcjhr/UQHAV7eplRYkAcleJZtFnvGEIOEkYzm3n8aFg/DvvzEtHPStU+8SmZ378u4BmPbSK4DNBRw11rjQRSDcZmcWpDudHeLoslX6liWIh0fmJvHxjBz9S93ofHCV7NAoYA9NnLqbZDVc12yCjiMfM4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785942527; c=relaxed/simple; bh=Xi1OgDbyB/Evc8ioBE8gFyoHFsNQEXX7oTxNLufPR/M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HLl+qyL9iW63Mx1LxJxd7puCuruDzXsQejOshfk1AnyHiu3ngTdALQfJNrJ47CSFl7EL2x70Zl2WsYO0k+z/eC2B9Qhyy3y2J/WrrIl0JrQGzxQrLEa9nzQRq+nVWiVuQ5hkLQtCwBPshCaGabmXjEiy/MQUQ94idybTNXyoVUA= 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=uYZ+1Xyy; arc=none smtp.client-ip=91.218.175.186 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="uYZ+1Xyy" 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=1785942519; 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: in-reply-to:in-reply-to:references:references; bh=AmGOoR5eHblWxTntREzpR+YPiusEuFcyx+N/a238v3o=; b=uYZ+1Xyymr+o0EfKUZB5tmSXYpHZIIxHrJaZ3FrgivNJuq085PdyzSxR2EFTHcPUJ+jLW7 ISCjUovSqjDz/KX1t5+mR/5PlcDbBspgwXhjETKb8qUY2lIx5OUDKC/QQMvY4f7wQMvLwE 7pZKlVSQlBCQ9QAFz5uYmcCU/3sR7rA= 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 1/2] bpf: Fix sleepable check for tracing/lsm prog Date: Wed, 5 Aug 2026 23:08:09 +0800 Message-ID: <20260805150810.34907-2-leon.hwang@linux.dev> In-Reply-To: <20260805150810.34907-1-leon.hwang@linux.dev> References: <20260805150810.34907-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@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. Fixes: 16d9c5660692 ("bpf: Always allow sleepable programs on syscalls") Fixes: 1e6c62a88215 ("bpf: Introduce sleepable BPF programs") Acked-by: Viktor Malik Signed-off-by: Leon Hwang --- kernel/bpf/verifier.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7439afdc851a..f364453a2ecb 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -19022,6 +19022,9 @@ static int btf_id_allow_sleepable(u32 btf_id, unsigned long addr, const struct b const struct btf_type *t; const char *tname; + if (!btf_is_kernel(btf)) + return -EINVAL; + switch (prog->type) { case BPF_PROG_TYPE_TRACING: t = btf_type_by_id(btf, btf_id); -- 2.55.0