Re: [PATCH] net: missing check

From: kernel test robot
Date: Fri Jun 07 2024 - 02:56:49 EST

Hi Denis,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.10-rc2 next-20240607]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Denis-Arefev/net-missing-check/20240606-230540
base: linus/master
patch link: https://lore.kernel.org/r/20240606141450.44709-1-arefev%40swemel.ru
patch subject: [PATCH] net: missing check
config: x86_64-randconfig-121-20240607 (https://download.01.org/0day-ci/archive/20240607/202406071404.OiLHfOHM-lkp@xxxxxxxxx/config)
compiler: gcc-13 (Ubuntu 13.2.0-4ubuntu3) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240607/202406071404.OiLHfOHM-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202406071404.OiLHfOHM-lkp@xxxxxxxxx/

sparse warnings: (new ones prefixed by >>)
drivers/net/virtio_net.c: note: in included file:
>> include/linux/virtio_net.h:103:58: sparse: sparse: incorrect type in argument 2 (different base types) @@ expected unsigned long long [usertype] divisor @@ got restricted __virtio16 const [usertype] gso_size @@
include/linux/virtio_net.h:103:58: sparse: expected unsigned long long [usertype] divisor
include/linux/virtio_net.h:103:58: sparse: got restricted __virtio16 const [usertype] gso_size
>> include/linux/virtio_net.h:104:42: sparse: sparse: restricted __virtio16 degrades to integer

vim +103 include/linux/virtio_net.h

49
50 static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
51 const struct virtio_net_hdr *hdr,
52 bool little_endian)
53 {
54 unsigned int nh_min_len = sizeof(struct iphdr);
55 unsigned int gso_type = 0;
56 unsigned int thlen = 0;
57 unsigned int p_off = 0;
58 unsigned int ip_proto;
59 u64 ret, remainder;
60
61 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
62 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
63 case VIRTIO_NET_HDR_GSO_TCPV4:
64 gso_type = SKB_GSO_TCPV4;
65 ip_proto = IPPROTO_TCP;
66 thlen = sizeof(struct tcphdr);
67 break;
68 case VIRTIO_NET_HDR_GSO_TCPV6:
69 gso_type = SKB_GSO_TCPV6;
70 ip_proto = IPPROTO_TCP;
71 thlen = sizeof(struct tcphdr);
72 nh_min_len = sizeof(struct ipv6hdr);
73 break;
74 case VIRTIO_NET_HDR_GSO_UDP:
75 gso_type = SKB_GSO_UDP;
76 ip_proto = IPPROTO_UDP;
77 thlen = sizeof(struct udphdr);
78 break;
79 case VIRTIO_NET_HDR_GSO_UDP_L4:
80 gso_type = SKB_GSO_UDP_L4;
81 ip_proto = IPPROTO_UDP;
82 thlen = sizeof(struct udphdr);
83 break;
84 default:
85 return -EINVAL;
86 }
87
88 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
89 gso_type |= SKB_GSO_TCP_ECN;
90
91 if (hdr->gso_size == 0)
92 return -EINVAL;
93 }
94
95 skb_reset_mac_header(skb);
96
97 if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
98 u32 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
99 u32 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
100 u32 needed = start + max_t(u32, thlen, off + sizeof(__sum16));
101
102 if (hdr->gso_size) {
> 103 ret = div64_u64_rem(skb->len, hdr->gso_size, &remainder);
> 104 if (!(ret && (hdr->gso_size > needed) &&
105 ((remainder > needed) || (remainder == 0)))) {
106 return -EINVAL;
107 }
108 skb_shinfo(skb)->tx_flags |= SKBFL_SHARED_FRAG;
109 }
110
111 if (!pskb_may_pull(skb, needed))
112 return -EINVAL;
113
114 if (!skb_partial_csum_set(skb, start, off))
115 return -EINVAL;
116
117 nh_min_len = max_t(u32, nh_min_len, skb_transport_offset(skb));
118 p_off = nh_min_len + thlen;
119 if (!pskb_may_pull(skb, p_off))
120 return -EINVAL;
121 } else {
122 /* gso packets without NEEDS_CSUM do not set transport_offset.
123 * probe and drop if does not match one of the above types.
124 */
125 if (gso_type && skb->network_header) {
126 struct flow_keys_basic keys;
127
128 if (!skb->protocol) {
129 __be16 protocol = dev_parse_header_protocol(skb);
130
131 if (!protocol)
132 virtio_net_hdr_set_proto(skb, hdr);
133 else if (!virtio_net_hdr_match_proto(protocol, hdr->gso_type))
134 return -EINVAL;
135 else
136 skb->protocol = protocol;
137 }
138 retry:
139 if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
140 NULL, 0, 0, 0,
141 0)) {
142 /* UFO does not specify ipv4 or 6: try both */
143 if (gso_type & SKB_GSO_UDP &&
144 skb->protocol == htons(ETH_P_IP)) {
145 skb->protocol = htons(ETH_P_IPV6);
146 goto retry;
147 }
148 return -EINVAL;
149 }
150
151 p_off = keys.control.thoff + thlen;
152 if (!pskb_may_pull(skb, p_off) ||
153 keys.basic.ip_proto != ip_proto)
154 return -EINVAL;
155
156 skb_set_transport_header(skb, keys.control.thoff);
157 } else if (gso_type) {
158 p_off = nh_min_len + thlen;
159 if (!pskb_may_pull(skb, p_off))
160 return -EINVAL;
161 }
162 }
163
164 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
165 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
166 unsigned int nh_off = p_off;
167 struct skb_shared_info *shinfo = skb_shinfo(skb);
168
169 switch (gso_type & ~SKB_GSO_TCP_ECN) {
170 case SKB_GSO_UDP:
171 /* UFO may not include transport header in gso_size. */
172 nh_off -= thlen;
173 break;
174 case SKB_GSO_UDP_L4:
175 if (!(hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM))
176 return -EINVAL;
177 if (skb->csum_offset != offsetof(struct udphdr, check))
178 return -EINVAL;
179 if (skb->len - p_off > gso_size * UDP_MAX_SEGMENTS)
180 return -EINVAL;
181 if (gso_type != SKB_GSO_UDP_L4)
182 return -EINVAL;
183 break;
184 }
185
186 /* Kernel has a special handling for GSO_BY_FRAGS. */
187 if (gso_size == GSO_BY_FRAGS)
188 return -EINVAL;
189
190 /* Too small packets are not really GSO ones. */
191 if (skb->len - nh_off > gso_size) {
192 shinfo->gso_size = gso_size;
193 shinfo->gso_type = gso_type;
194
195 /* Header must be checked, and gso_segs computed. */
196 shinfo->gso_type |= SKB_GSO_DODGY;
197 shinfo->gso_segs = 0;
198 }
199 }
200
201 return 0;
202 }
203

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki