From patchwork Tue Nov 19 22:44:31 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jakub Kicinski X-Patchwork-Id: 13880616 X-Patchwork-Delegate: kuba@kernel.org 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 813331BBBD3 for ; Tue, 19 Nov 2024 22:44:37 +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=1732056277; cv=none; b=BYziE2qUcaDr5ACAf5bjVR4y66UPsnqyZ3mnOz4tFtR6jf1or1FjebleLdkMgAukWPXedl6M/eZZRFL+nQ3cIAubtzCdetz4SWNVl08ODGct1h4u20+xWY7cUlMaqHbr/QHIC1JDe7C6C8vUopujL4qvjWckiE2LyA7cgfgWDto= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732056277; c=relaxed/simple; bh=Gn4XjLvrdElZ61Q3hQ7/HcT3g68zcnVnwjENfbyBM2Q=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=EHPlm2XBxZDKJqJLzzYnvPEx1fKj9dyRAOq2v7uEtnwXLP8/jq0lh9IquV2csUfaoVRQ/iatU40wb+SlxpuJLssAXiJP/L7SvkBn4YX152obggCnGgSE30esB/k9Yk44h4tv5Ab5uPziNiHq8spLXLYaNtdqSdNqA798F2cSGFI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=I2NmGdEA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="I2NmGdEA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C14E9C4CECF; Tue, 19 Nov 2024 22:44:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732056277; bh=Gn4XjLvrdElZ61Q3hQ7/HcT3g68zcnVnwjENfbyBM2Q=; h=From:To:Cc:Subject:Date:From; b=I2NmGdEAirAe6s1m082KixbL8Uex/7AyGg8XJboPxupgtXikxtVaPipOR0QHAYgt+ qvV316xVzaC7iHwEunqtTU6ne4B5t6Bou0Tzg9djNKxqW27YaUNaH8cqwNqhpRFSDR uspYX6vfrr9gs2BfT0nvXT6NnXFstcETMLKcP+64vSKeHvmPWnT02tuRO33eN/BhiQ A53VU5FNx6kSTuKR9j0pISc31Xjq9/Qisq5IDXT26RqCgAnVh65sg8w41roXD4Gt+1 FV5usmwM2GVkM9+K4wjvXF2dmxtWqAO7GvGPOA7gO0MGGFR/wtg3X1V3uM+OBXGrSw VgT2eOegLIPHA== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, Jakub Kicinski , syzbot+d4373fa8042c06cefa84@syzkaller.appspotmail.com, dsahern@kernel.org Subject: [PATCH net v2 1/2] netlink: fix false positive warning in extack during dumps Date: Tue, 19 Nov 2024 14:44:31 -0800 Message-ID: <20241119224432.1713040-1-kuba@kernel.org> X-Mailer: git-send-email 2.47.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Commit under fixes extended extack reporting to dumps. It works under normal conditions, because extack errors are usually reported during ->start() or the first ->dump(), it's quite rare that the dump starts okay but fails later. If the dump does fail later, however, the input skb will already have the initiating message pulled, so checking if bad attr falls within skb->data will fail. Switch the check to using nlh, which is always valid. syzbot found a way to hit that scenario by filling up the receive queue. In this case we initiate a dump but don't call ->dump() until there is read space for an skb. WARNING: CPU: 1 PID: 5845 at net/netlink/af_netlink.c:2210 netlink_ack_tlv_fill+0x1a8/0x560 net/netlink/af_netlink.c:2209 RIP: 0010:netlink_ack_tlv_fill+0x1a8/0x560 net/netlink/af_netlink.c:2209 Call Trace: netlink_dump_done+0x513/0x970 net/netlink/af_netlink.c:2250 netlink_dump+0x91f/0xe10 net/netlink/af_netlink.c:2351 netlink_recvmsg+0x6bb/0x11d0 net/netlink/af_netlink.c:1983 sock_recvmsg_nosec net/socket.c:1051 [inline] sock_recvmsg+0x22f/0x280 net/socket.c:1073 __sys_recvfrom+0x246/0x3d0 net/socket.c:2267 __do_sys_recvfrom net/socket.c:2285 [inline] __se_sys_recvfrom net/socket.c:2281 [inline] __x64_sys_recvfrom+0xde/0x100 net/socket.c:2281 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff37dd17a79 Reported-by: syzbot+d4373fa8042c06cefa84@syzkaller.appspotmail.com Fixes: 8af4f60472fc ("netlink: support all extack types in dumps") Signed-off-by: Jakub Kicinski --- v2: - move the helper to af_netlink.c and move the WARN_ON() inside v1: https://lore.kernel.org/20241115003150.733141-1-kuba@kernel.org CC: dsahern@kernel.org --- net/netlink/af_netlink.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index f84aad420d44..775d707ec708 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2176,9 +2176,14 @@ netlink_ack_tlv_len(struct netlink_sock *nlk, int err, return tlvlen; } +static bool nlmsg_check_in_payload(const struct nlmsghdr *nlh, const void *addr) +{ + return !WARN_ON(addr < nlmsg_data(nlh) || + addr - (const void *) nlh >= nlh->nlmsg_len); +} + static void -netlink_ack_tlv_fill(struct sk_buff *in_skb, struct sk_buff *skb, - const struct nlmsghdr *nlh, int err, +netlink_ack_tlv_fill(struct sk_buff *skb, const struct nlmsghdr *nlh, int err, const struct netlink_ext_ack *extack) { if (extack->_msg) @@ -2190,9 +2195,7 @@ netlink_ack_tlv_fill(struct sk_buff *in_skb, struct sk_buff *skb, if (!err) return; - if (extack->bad_attr && - !WARN_ON((u8 *)extack->bad_attr < in_skb->data || - (u8 *)extack->bad_attr >= in_skb->data + in_skb->len)) + if (extack->bad_attr && nlmsg_check_in_payload(nlh, extack->bad_attr)) WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, (u8 *)extack->bad_attr - (const u8 *)nlh)); if (extack->policy) @@ -2201,9 +2204,7 @@ netlink_ack_tlv_fill(struct sk_buff *in_skb, struct sk_buff *skb, if (extack->miss_type) WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_TYPE, extack->miss_type)); - if (extack->miss_nest && - !WARN_ON((u8 *)extack->miss_nest < in_skb->data || - (u8 *)extack->miss_nest > in_skb->data + in_skb->len)) + if (extack->miss_nest && nlmsg_check_in_payload(nlh, extack->miss_nest)) WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_NEST, (u8 *)extack->miss_nest - (const u8 *)nlh)); } @@ -2232,7 +2233,7 @@ static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb, if (extack_len) { nlh->nlmsg_flags |= NLM_F_ACK_TLVS; if (skb_tailroom(skb) >= extack_len) { - netlink_ack_tlv_fill(cb->skb, skb, cb->nlh, + netlink_ack_tlv_fill(skb, cb->nlh, nlk->dump_done_errno, extack); nlmsg_end(skb, nlh); } @@ -2491,7 +2492,7 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, } if (tlvlen) - netlink_ack_tlv_fill(in_skb, skb, nlh, err, extack); + netlink_ack_tlv_fill(skb, nlh, err, extack); nlmsg_end(skb, rep); From patchwork Tue Nov 19 22:44:32 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jakub Kicinski X-Patchwork-Id: 13880617 X-Patchwork-Delegate: kuba@kernel.org 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 1DA611D26FE; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FyCm3wv7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E017C4CED9; Tue, 19 Nov 2024 22:44:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732056277; bh=LdyZfhGLcAffeQWdZ9vyCIw4OGV0nYZirm1HjPWiJ4c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FyCm3wv7BxIeFqGVT5Ng/dmBoitRqlUrcSdMlmEm7PogGxoF6Xq16THbvsKXa1ikr CrvDFMcTMNR/2tCBnyrN8QQFpXuUyHp5/fl+tEQC+4i96jguMP+k7e4vfep7OOyMZD XpHaw2cvfSP2oODQMd2hQCJ73qmt1A8omF23QcTQ4O/LjI1oGJpzPk6nrCqB8aEd5G mSgsnvWZjHzGEOK7EhpsAtz9EGVb37C4S+1bxIMp8hzS32GbJvmdU6FEUSYNT1Z0R2 iGEJp5bzZxvCoYgwsXVVtKeZdRy3BEJkWMpbrlRd819AcIcuF5/MrzkV2b7WkDKQam 2Vn48OLYy3Omg== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, Jakub Kicinski , linux-kselftest@vger.kernel.org Subject: [PATCH net v2 2/2] selftests: net: test extacks in netlink dumps Date: Tue, 19 Nov 2024 14:44:32 -0800 Message-ID: <20241119224432.1713040-2-kuba@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241119224432.1713040-1-kuba@kernel.org> References: <20241119224432.1713040-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Test that extacks in dumps work. The test fills up the receive buffer to test both the inline dump (as part of sendmsg()) and delayed one (run during recvmsg()). Use YNL helpers to parse the messages. We need to add the test to YNL file to make sure the right include path are used. Signed-off-by: Jakub Kicinski --- CC: linux-kselftest@vger.kernel.org --- tools/testing/selftests/net/Makefile | 3 +- tools/testing/selftests/net/netlink-dumps.c | 129 ++++++++++++++++++++ 2 files changed, 130 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index 5e86f7a51b43..c427ee32b193 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -78,7 +78,6 @@ TEST_PROGS += test_vxlan_vnifiltering.sh TEST_GEN_FILES += io_uring_zerocopy_tx TEST_PROGS += io_uring_zerocopy_tx.sh TEST_GEN_FILES += bind_bhash -TEST_GEN_PROGS += netlink-dumps TEST_GEN_PROGS += sk_bind_sendto_listen TEST_GEN_PROGS += sk_connect_zero_addr TEST_GEN_PROGS += sk_so_peek_off @@ -100,7 +99,7 @@ TEST_PROGS += bpf_offload.py # YNL files, must be before "include ..lib.mk" EXTRA_CLEAN += $(OUTPUT)/libynl.a -YNL_GEN_FILES := ncdevmem +YNL_GEN_FILES := ncdevmem netlink-dumps TEST_GEN_FILES += $(YNL_GEN_FILES) TEST_FILES := settings diff --git a/tools/testing/selftests/net/netlink-dumps.c b/tools/testing/selftests/net/netlink-dumps.c index 7ee6dcd334df..195febbf6a61 100644 --- a/tools/testing/selftests/net/netlink-dumps.c +++ b/tools/testing/selftests/net/netlink-dumps.c @@ -12,11 +12,140 @@ #include #include +#include +#include #include #include +#include #include "../kselftest_harness.h" +#include + +struct ext_ack { + int err; + + __u32 attr_offs; + __u32 miss_type; + __u32 miss_nest; + const char *str; +}; + +/* 0: no done, 1: done found, 2: extack found, -1: error */ +static int nl_get_extack(char *buf, size_t n, struct ext_ack *ea) +{ + const struct nlmsghdr *nlh; + const struct nlattr *attr; + ssize_t rem; + + for (rem = n; rem > 0; NLMSG_NEXT(nlh, rem)) { + nlh = (struct nlmsghdr *)&buf[n - rem]; + if (!NLMSG_OK(nlh, rem)) + return -1; + + if (nlh->nlmsg_type != NLMSG_DONE) + continue; + + ea->err = -*(int *)NLMSG_DATA(nlh); + + if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS)) + return 1; + + ynl_attr_for_each(attr, nlh, sizeof(int)) { + switch (ynl_attr_type(attr)) { + case NLMSGERR_ATTR_OFFS: + ea->attr_offs = ynl_attr_get_u32(attr); + break; + case NLMSGERR_ATTR_MISS_TYPE: + ea->miss_type = ynl_attr_get_u32(attr); + break; + case NLMSGERR_ATTR_MISS_NEST: + ea->miss_nest = ynl_attr_get_u32(attr); + break; + case NLMSGERR_ATTR_MSG: + ea->str = ynl_attr_get_str(attr); + break; + } + } + + return 2; + } + + return 0; +} + +static const struct { + struct nlmsghdr nlhdr; + struct ndmsg ndm; + struct nlattr ahdr; + __u32 val; +} dump_neigh_bad = { + .nlhdr = { + .nlmsg_len = sizeof(dump_neigh_bad), + .nlmsg_type = RTM_GETNEIGH, + .nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP, + .nlmsg_seq = 1, + }, + .ndm = { + .ndm_family = 123, + }, + .ahdr = { + .nla_len = 4 + 4, + .nla_type = NDA_FLAGS_EXT, + }, + .val = -1, // should fail MASK validation +}; + +TEST(dump_extack) +{ + int netlink_sock; + char buf[8192]; + int one = 1; + int i, cnt; + ssize_t n; + + netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); + ASSERT_GE(netlink_sock, 0); + + n = setsockopt(netlink_sock, SOL_NETLINK, NETLINK_CAP_ACK, + &one, sizeof(one)); + ASSERT_EQ(n, 0); + n = setsockopt(netlink_sock, SOL_NETLINK, NETLINK_EXT_ACK, + &one, sizeof(one)); + ASSERT_EQ(n, 0); + n = setsockopt(netlink_sock, SOL_NETLINK, NETLINK_GET_STRICT_CHK, + &one, sizeof(one)); + ASSERT_EQ(n, 0); + + /* Dump so many times we fill up the buffer */ + cnt = 64; + for (i = 0; i < cnt; i++) { + n = send(netlink_sock, &dump_neigh_bad, + sizeof(dump_neigh_bad), 0); + ASSERT_EQ(n, sizeof(dump_neigh_bad)); + } + + /* Read out the ENOBUFS */ + n = recv(netlink_sock, buf, sizeof(buf), MSG_DONTWAIT); + EXPECT_EQ(n, -1); + EXPECT_EQ(errno, ENOBUFS); + + for (i = 0; i < cnt; i++) { + struct ext_ack ea = {}; + + n = recv(netlink_sock, buf, sizeof(buf), MSG_DONTWAIT); + if (n < 0) { + ASSERT_GE(i, 10); + break; + } + ASSERT_GE(n, (ssize_t)sizeof(struct nlmsghdr)); + + EXPECT_EQ(nl_get_extack(buf, n, &ea), 2); + EXPECT_EQ(ea.attr_offs, + sizeof(struct nlmsghdr) + sizeof(struct ndmsg)); + } +} + static const struct { struct nlmsghdr nlhdr; struct genlmsghdr genlhdr;