From 4e9505064f58d1252805952f8547a5b7dbc5c111 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Sat, 17 Jul 2021 16:02:21 +0100 Subject: [PATCH 1/2] net/xfrm/compat: Copy xfrm_spdattr_type_t atributes The attribute-translator has to take in mind maxtype, that is xfrm_link::nla_max. When it is set, attributes are not of xfrm_attr_type_t. Currently, they can be only XFRMA_SPD_MAX (message XFRM_MSG_NEWSPDINFO), their UABI is the same for 64/32-bit, so just copy them. Thanks to YueHaibing for reporting this: In xfrm_user_rcv_msg_compat() if maxtype is not zero and less than XFRMA_MAX, nlmsg_parse_deprecated() do not initialize attrs array fully. xfrm_xlate32() will access uninit 'attrs[i]' while iterating all attrs array. KASAN: probably user-memory-access in range [0x0000000041b58ab0-0x0000000041b58ab7] CPU: 0 PID: 15799 Comm: syz-executor.2 Tainted: G W 5.14.0-rc1-syzkaller #0 RIP: 0010:nla_type include/net/netlink.h:1130 [inline] RIP: 0010:xfrm_xlate32_attr net/xfrm/xfrm_compat.c:410 [inline] RIP: 0010:xfrm_xlate32 net/xfrm/xfrm_compat.c:532 [inline] RIP: 0010:xfrm_user_rcv_msg_compat+0x5e5/0x1070 net/xfrm/xfrm_compat.c:577 [...] Call Trace: xfrm_user_rcv_msg+0x556/0x8b0 net/xfrm/xfrm_user.c:2774 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 xfrm_netlink_rcv+0x6b/0x90 net/xfrm/xfrm_user.c:2824 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:702 [inline] Fixes: 5106f4a8acff ("xfrm/compat: Add 32=>64-bit messages translator") Cc: Reported-by: YueHaibing Signed-off-by: Dmitry Safonov Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_compat.c | 49 +++++++++++++++++++++++++++++++++++++----- 1 file changed, 44 insertions(+), 5 deletions(-) diff --git a/net/xfrm/xfrm_compat.c b/net/xfrm/xfrm_compat.c index a20aec9d7393..2bf269390163 100644 --- a/net/xfrm/xfrm_compat.c +++ b/net/xfrm/xfrm_compat.c @@ -298,8 +298,16 @@ static int xfrm_xlate64(struct sk_buff *dst, const struct nlmsghdr *nlh_src) len = nlmsg_attrlen(nlh_src, xfrm_msg_min[type]); nla_for_each_attr(nla, attrs, len, remaining) { - int err = xfrm_xlate64_attr(dst, nla); + int err; + switch (type) { + case XFRM_MSG_NEWSPDINFO: + err = xfrm_nla_cpy(dst, nla, nla_len(nla)); + break; + default: + err = xfrm_xlate64_attr(dst, nla); + break; + } if (err) return err; } @@ -341,7 +349,8 @@ static int xfrm_alloc_compat(struct sk_buff *skb, const struct nlmsghdr *nlh_src /* Calculates len of translated 64-bit message. */ static size_t xfrm_user_rcv_calculate_len64(const struct nlmsghdr *src, - struct nlattr *attrs[XFRMA_MAX+1]) + struct nlattr *attrs[XFRMA_MAX + 1], + int maxtype) { size_t len = nlmsg_len(src); @@ -358,10 +367,20 @@ static size_t xfrm_user_rcv_calculate_len64(const struct nlmsghdr *src, case XFRM_MSG_POLEXPIRE: len += 8; break; + case XFRM_MSG_NEWSPDINFO: + /* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */ + return len; default: break; } + /* Unexpected for anything, but XFRM_MSG_NEWSPDINFO, please + * correct both 64=>32-bit and 32=>64-bit translators to copy + * new attributes. + */ + if (WARN_ON_ONCE(maxtype)) + return len; + if (attrs[XFRMA_SA]) len += 4; if (attrs[XFRMA_POLICY]) @@ -440,7 +459,8 @@ static int xfrm_xlate32_attr(void *dst, const struct nlattr *nla, static int xfrm_xlate32(struct nlmsghdr *dst, const struct nlmsghdr *src, struct nlattr *attrs[XFRMA_MAX+1], - size_t size, u8 type, struct netlink_ext_ack *extack) + size_t size, u8 type, int maxtype, + struct netlink_ext_ack *extack) { size_t pos; int i; @@ -520,6 +540,25 @@ static int xfrm_xlate32(struct nlmsghdr *dst, const struct nlmsghdr *src, } pos = dst->nlmsg_len; + if (maxtype) { + /* attirbutes are xfrm_spdattr_type_t, not xfrm_attr_type_t */ + WARN_ON_ONCE(src->nlmsg_type != XFRM_MSG_NEWSPDINFO); + + for (i = 1; i <= maxtype; i++) { + int err; + + if (!attrs[i]) + continue; + + /* just copy - no need for translation */ + err = xfrm_attr_cpy32(dst, &pos, attrs[i], size, + nla_len(attrs[i]), nla_len(attrs[i])); + if (err) + return err; + } + return 0; + } + for (i = 1; i < XFRMA_MAX + 1; i++) { int err; @@ -564,7 +603,7 @@ static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32, if (err < 0) return ERR_PTR(err); - len = xfrm_user_rcv_calculate_len64(h32, attrs); + len = xfrm_user_rcv_calculate_len64(h32, attrs, maxtype); /* The message doesn't need translation */ if (len == nlmsg_len(h32)) return NULL; @@ -574,7 +613,7 @@ static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32, if (!h64) return ERR_PTR(-ENOMEM); - err = xfrm_xlate32(h64, h32, attrs, len, type, extack); + err = xfrm_xlate32(h64, h32, attrs, len, type, maxtype, extack); if (err < 0) { kvfree(h64); return ERR_PTR(err); From 70bfdf62e93a4d73cfbaf83a3ac708a483ef7a71 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Sat, 17 Jul 2021 16:02:22 +0100 Subject: [PATCH 2/2] selftests/net/ipsec: Add test for xfrm_spdattr_type_t Set hthresh, dump it again and verify thresh.lbits && thresh.rbits. They are passed as attributes of xfrm_spdattr_type_t, different from other message attributes that use xfrm_attr_type_t. Also, test attribute that is bigger than XFRMA_SPD_MAX, currently it should be silently ignored. Cc: Shuah Khan Cc: linux-kselftest@vger.kernel.org Signed-off-by: Dmitry Safonov Signed-off-by: Steffen Klassert --- tools/testing/selftests/net/ipsec.c | 165 +++++++++++++++++++++++++++- 1 file changed, 163 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/net/ipsec.c b/tools/testing/selftests/net/ipsec.c index f23438d512c5..3d7dde2c321b 100644 --- a/tools/testing/selftests/net/ipsec.c +++ b/tools/testing/selftests/net/ipsec.c @@ -484,13 +484,16 @@ enum desc_type { MONITOR_ACQUIRE, EXPIRE_STATE, EXPIRE_POLICY, + SPDINFO_ATTRS, }; const char *desc_name[] = { "create tunnel", "alloc spi", "monitor acquire", "expire state", - "expire policy" + "expire policy", + "spdinfo attributes", + "" }; struct xfrm_desc { enum desc_type type; @@ -1593,6 +1596,155 @@ static int xfrm_expire_policy(int xfrm_sock, uint32_t *seq, return ret; } +static int xfrm_spdinfo_set_thresh(int xfrm_sock, uint32_t *seq, + unsigned thresh4_l, unsigned thresh4_r, + unsigned thresh6_l, unsigned thresh6_r, + bool add_bad_attr) + +{ + struct { + struct nlmsghdr nh; + union { + uint32_t unused; + int error; + }; + char attrbuf[MAX_PAYLOAD]; + } req; + struct xfrmu_spdhthresh thresh; + + memset(&req, 0, sizeof(req)); + req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.unused)); + req.nh.nlmsg_type = XFRM_MSG_NEWSPDINFO; + req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; + req.nh.nlmsg_seq = (*seq)++; + + thresh.lbits = thresh4_l; + thresh.rbits = thresh4_r; + if (rtattr_pack(&req.nh, sizeof(req), XFRMA_SPD_IPV4_HTHRESH, &thresh, sizeof(thresh))) + return -1; + + thresh.lbits = thresh6_l; + thresh.rbits = thresh6_r; + if (rtattr_pack(&req.nh, sizeof(req), XFRMA_SPD_IPV6_HTHRESH, &thresh, sizeof(thresh))) + return -1; + + if (add_bad_attr) { + BUILD_BUG_ON(XFRMA_IF_ID <= XFRMA_SPD_MAX + 1); + if (rtattr_pack(&req.nh, sizeof(req), XFRMA_IF_ID, NULL, 0)) { + pr_err("adding attribute failed: no space"); + return -1; + } + } + + if (send(xfrm_sock, &req, req.nh.nlmsg_len, 0) < 0) { + pr_err("send()"); + return -1; + } + + if (recv(xfrm_sock, &req, sizeof(req), 0) < 0) { + pr_err("recv()"); + return -1; + } else if (req.nh.nlmsg_type != NLMSG_ERROR) { + printk("expected NLMSG_ERROR, got %d", (int)req.nh.nlmsg_type); + return -1; + } + + if (req.error) { + printk("NLMSG_ERROR: %d: %s", req.error, strerror(-req.error)); + return -1; + } + + return 0; +} + +static int xfrm_spdinfo_attrs(int xfrm_sock, uint32_t *seq) +{ + struct { + struct nlmsghdr nh; + union { + uint32_t unused; + int error; + }; + char attrbuf[MAX_PAYLOAD]; + } req; + + if (xfrm_spdinfo_set_thresh(xfrm_sock, seq, 32, 31, 120, 16, false)) { + pr_err("Can't set SPD HTHRESH"); + return KSFT_FAIL; + } + + memset(&req, 0, sizeof(req)); + + req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.unused)); + req.nh.nlmsg_type = XFRM_MSG_GETSPDINFO; + req.nh.nlmsg_flags = NLM_F_REQUEST; + req.nh.nlmsg_seq = (*seq)++; + if (send(xfrm_sock, &req, req.nh.nlmsg_len, 0) < 0) { + pr_err("send()"); + return KSFT_FAIL; + } + + if (recv(xfrm_sock, &req, sizeof(req), 0) < 0) { + pr_err("recv()"); + return KSFT_FAIL; + } else if (req.nh.nlmsg_type == XFRM_MSG_NEWSPDINFO) { + size_t len = NLMSG_PAYLOAD(&req.nh, sizeof(req.unused)); + struct rtattr *attr = (void *)req.attrbuf; + int got_thresh = 0; + + for (; RTA_OK(attr, len); attr = RTA_NEXT(attr, len)) { + if (attr->rta_type == XFRMA_SPD_IPV4_HTHRESH) { + struct xfrmu_spdhthresh *t = RTA_DATA(attr); + + got_thresh++; + if (t->lbits != 32 || t->rbits != 31) { + pr_err("thresh differ: %u, %u", + t->lbits, t->rbits); + return KSFT_FAIL; + } + } + if (attr->rta_type == XFRMA_SPD_IPV6_HTHRESH) { + struct xfrmu_spdhthresh *t = RTA_DATA(attr); + + got_thresh++; + if (t->lbits != 120 || t->rbits != 16) { + pr_err("thresh differ: %u, %u", + t->lbits, t->rbits); + return KSFT_FAIL; + } + } + } + if (got_thresh != 2) { + pr_err("only %d thresh returned by XFRM_MSG_GETSPDINFO", got_thresh); + return KSFT_FAIL; + } + } else if (req.nh.nlmsg_type != NLMSG_ERROR) { + printk("expected NLMSG_ERROR, got %d", (int)req.nh.nlmsg_type); + return KSFT_FAIL; + } else { + printk("NLMSG_ERROR: %d: %s", req.error, strerror(-req.error)); + return -1; + } + + /* Restore the default */ + if (xfrm_spdinfo_set_thresh(xfrm_sock, seq, 32, 32, 128, 128, false)) { + pr_err("Can't restore SPD HTHRESH"); + return KSFT_FAIL; + } + + /* + * At this moment xfrm uses nlmsg_parse_deprecated(), which + * implies NL_VALIDATE_LIBERAL - ignoring attributes with + * (type > maxtype). nla_parse_depricated_strict() would enforce + * it. Or even stricter nla_parse(). + * Right now it's not expected to fail, but to be ignored. + */ + if (xfrm_spdinfo_set_thresh(xfrm_sock, seq, 32, 32, 128, 128, true)) + return KSFT_PASS; + + return KSFT_PASS; +} + static int child_serv(int xfrm_sock, uint32_t *seq, unsigned int nr, int cmd_fd, void *buf, struct xfrm_desc *desc) { @@ -1717,6 +1869,9 @@ static int child_f(unsigned int nr, int test_desc_fd, int cmd_fd, void *buf) case EXPIRE_POLICY: ret = xfrm_expire_policy(xfrm_sock, &seq, nr, &desc); break; + case SPDINFO_ATTRS: + ret = xfrm_spdinfo_attrs(xfrm_sock, &seq); + break; default: printk("Unknown desc type %d", desc.type); exit(KSFT_FAIL); @@ -1994,8 +2149,10 @@ static int write_proto_plan(int fd, int proto) * sizeof(xfrm_user_polexpire) = 168 | sizeof(xfrm_user_polexpire) = 176 * * Check the affected by the UABI difference structures. + * Also, check translation for xfrm_set_spdinfo: it has it's own attributes + * which needs to be correctly copied, but not translated. */ -const unsigned int compat_plan = 4; +const unsigned int compat_plan = 5; static int write_compat_struct_tests(int test_desc_fd) { struct xfrm_desc desc = {}; @@ -2019,6 +2176,10 @@ static int write_compat_struct_tests(int test_desc_fd) if (__write_desc(test_desc_fd, &desc)) return -1; + desc.type = SPDINFO_ATTRS; + if (__write_desc(test_desc_fd, &desc)) + return -1; + return 0; }