From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E2AB514293; Tue, 2 Jul 2024 17:21:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719940867; cv=none; b=Ib5+b4MoS0++b2pmM7zn3Ku6vIsZguUO1AlgGYh6evbecxf2edOH5IXWBsQByXW+g9Cu5JxMhfHqO4NqQ7nbAaNQAvVx0SOuBSVdkLiRQpc+Blj1gYscXVO/evvSIvicBKQ34dDtn45i0Dm/gu0R7ZcPv6s2G7OG5c5P9O9NTAw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719940867; c=relaxed/simple; bh=GYKGm4JdOtQEg92vAwkJNyXx+7LlBVXiOvUTpOj/bGE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TcasGWta29ApcILob9eDWwvz8UvBzx9u+xQPJiDVCpqCIkf18C7lenzUcIq/sOS1acYm9tfdIaJy7PlR0fQy4g1uh2muNW70AcdJwibmZKuA6cGqegqOh3ZuX5J/uo0tB0naN11PdiPu+L3EyJctFJ9tRgtS0Gj0qBbV0IyVGMc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pu0iK+mW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pu0iK+mW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21AE5C116B1; Tue, 2 Jul 2024 17:21:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1719940866; bh=GYKGm4JdOtQEg92vAwkJNyXx+7LlBVXiOvUTpOj/bGE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pu0iK+mWYwWmyKnG2EQwfj68nsM0Pqh87x5Uf79MkthqP++UvNl6KX6fHSVCNCzlA ijZTjZFsVS/CaD/tgnHZcahdViFRj64+DJoUPQUMU7LRW7OfvibwdkTD4i8OdXxao3 Ae8b+eviebmym9qODlScYH9LMa0h5dv3xVCRlbTM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+603bcd9b0bf1d94dbb9b@syzkaller.appspotmail.com, syzbot+eb02dc7f03dce0ef39f3@syzkaller.appspotmail.com, syzbot+b4e65ca24fd4d0c734c3@syzkaller.appspotmail.com, syzbot+d2b113dc9fea5e1d2848@syzkaller.appspotmail.com, syzbot+1a3cf6f08d68868f9db3@syzkaller.appspotmail.com, Yonghong Song , Alexei Starovoitov , Martin KaFai Lau , Sasha Levin Subject: [PATCH 6.6 059/163] bpf: Mark bpf prog stack with kmsan_unposion_memory in interpreter mode Date: Tue, 2 Jul 2024 19:02:53 +0200 Message-ID: <20240702170235.298944140@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240702170233.048122282@linuxfoundation.org> References: <20240702170233.048122282@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin KaFai Lau [ Upstream commit e8742081db7d01f980c6161ae1e8a1dbc1e30979 ] syzbot reported uninit memory usages during map_{lookup,delete}_elem. ========== BUG: KMSAN: uninit-value in __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline] BUG: KMSAN: uninit-value in dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796 __dev_map_lookup_elem kernel/bpf/devmap.c:441 [inline] dev_map_lookup_elem+0xf3/0x170 kernel/bpf/devmap.c:796 ____bpf_map_lookup_elem kernel/bpf/helpers.c:42 [inline] bpf_map_lookup_elem+0x5c/0x80 kernel/bpf/helpers.c:38 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997 __bpf_prog_run256+0xb5/0xe0 kernel/bpf/core.c:2237 ========== The reproducer should be in the interpreter mode. The C reproducer is trying to run the following bpf prog: 0: (18) r0 = 0x0 2: (18) r1 = map[id:49] 4: (b7) r8 = 16777216 5: (7b) *(u64 *)(r10 -8) = r8 6: (bf) r2 = r10 7: (07) r2 += -229 ^^^^^^^^^^ 8: (b7) r3 = 8 9: (b7) r4 = 0 10: (85) call dev_map_lookup_elem#1543472 11: (95) exit It is due to the "void *key" (r2) passed to the helper. bpf allows uninit stack memory access for bpf prog with the right privileges. This patch uses kmsan_unpoison_memory() to mark the stack as initialized. This should address different syzbot reports on the uninit "void *key" argument during map_{lookup,delete}_elem. Reported-by: syzbot+603bcd9b0bf1d94dbb9b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/bpf/000000000000f9ce6d061494e694@google.com/ Reported-by: syzbot+eb02dc7f03dce0ef39f3@syzkaller.appspotmail.com Closes: https://lore.kernel.org/bpf/000000000000a5c69c06147c2238@google.com/ Reported-by: syzbot+b4e65ca24fd4d0c734c3@syzkaller.appspotmail.com Closes: https://lore.kernel.org/bpf/000000000000ac56fb06143b6cfa@google.com/ Reported-by: syzbot+d2b113dc9fea5e1d2848@syzkaller.appspotmail.com Closes: https://lore.kernel.org/bpf/0000000000000d69b206142d1ff7@google.com/ Reported-by: syzbot+1a3cf6f08d68868f9db3@syzkaller.appspotmail.com Closes: https://lore.kernel.org/bpf/0000000000006f876b061478e878@google.com/ Tested-by: syzbot+1a3cf6f08d68868f9db3@syzkaller.appspotmail.com Suggested-by: Yonghong Song Suggested-by: Alexei Starovoitov Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20240328185801.1843078-1-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- kernel/bpf/core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index bdbce41d1bb4a..77a9b12e00af7 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2174,6 +2174,7 @@ static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn u64 stack[stack_size / sizeof(u64)]; \ u64 regs[MAX_BPF_EXT_REG] = {}; \ \ + kmsan_unpoison_memory(stack, sizeof(stack)); \ FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ ARG1 = (u64) (unsigned long) ctx; \ return ___bpf_prog_run(regs, insn); \ @@ -2187,6 +2188,7 @@ static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ u64 stack[stack_size / sizeof(u64)]; \ u64 regs[MAX_BPF_EXT_REG]; \ \ + kmsan_unpoison_memory(stack, sizeof(stack)); \ FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ BPF_R1 = r1; \ BPF_R2 = r2; \ -- 2.43.0