kernel/linux.git/include/uapi/linux/if_packet.h, branch v6.6.131

af_packet: Fix fortified memcpy() without flex array.

2023-10-12T07:15:15+00:00

Sergei Trofimovich reported a regression [0] caused by commit a0ade8404c3b ("af_packet: Fix warning of fortified memcpy() in packet_getname()."). It introduced a flex array sll_addr_flex in struct sockaddr_ll as a union-ed member with sll_addr to work around the fortified memcpy() check. However, a userspace program uses a struct that has struct sockaddr_ll in the middle, where a flex array is illegal to exist. include/linux/if_packet.h:24:17: error: flexible array member 'sockaddr_ll::::::sll_addr_flex' not at end of 'struct packet_info_t' 24 | __DECLARE_FLEX_ARRAY(unsigned char, sll_addr_flex); | ^~~~~~~~~~~~~~~~~~~~ To fix the regression, let's go back to the first attempt [1] telling memcpy() the actual size of the array. Reported-by: Sergei Trofimovich Closes: https://github.com/NixOS/nixpkgs/pull/252587#issuecomment-1741733002 [0] Link: https://lore.kernel.org/netdev/20230720004410.87588-3-kuniyu@amazon.com/ [1] Fixes: a0ade8404c3b ("af_packet: Fix warning of fortified memcpy() in packet_getname().") Signed-off-by: Kuniyuki Iwashima Link: https://lore.kernel.org/r/20231009153151.75688-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni

af_packet: Fix warning of fortified memcpy() in packet_getname().

2023-07-26T03:10:05+00:00

syzkaller found a warning in packet_getname() [0], where we try to copy 16 bytes to sockaddr_ll.sll_addr[8]. Some devices (ip6gre, vti6, ip6tnl) have 16 bytes address expressed by struct in6_addr. Also, Infiniband has 32 bytes as MAX_ADDR_LEN. The write seems to overflow, but actually not since we use struct sockaddr_storage defined in __sys_getsockname() and its size is 128 (_K_SS_MAXSIZE) bytes. Thus, we have sufficient room after sll_addr[] as __data[]. To avoid the warning, let's add a flex array member union-ed with sll_addr. Another option would be to use strncpy() and limit the copied length to sizeof(sll_addr), but it will return the partial address and break an application that passes sockaddr_storage to getsockname(). [0]: memcpy: detected field-spanning write (size 16) of single field "sll->sll_addr" at net/packet/af_packet.c:3604 (size 8) WARNING: CPU: 0 PID: 255 at net/packet/af_packet.c:3604 packet_getname+0x25c/0x3a0 net/packet/af_packet.c:3604 Modules linked in: CPU: 0 PID: 255 Comm: syz-executor750 Not tainted 6.5.0-rc1-00330-g60cc1f7d0605 #4 Hardware name: linux,dummy-virt (DT) pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : packet_getname+0x25c/0x3a0 net/packet/af_packet.c:3604 lr : packet_getname+0x25c/0x3a0 net/packet/af_packet.c:3604 sp : ffff800089887bc0 x29: ffff800089887bc0 x28: ffff000010f80f80 x27: 0000000000000003 x26: dfff800000000000 x25: ffff700011310f80 x24: ffff800087d55000 x23: dfff800000000000 x22: ffff800089887c2c x21: 0000000000000010 x20: ffff00000de08310 x19: ffff800089887c20 x18: ffff800086ab1630 x17: 20646c6569662065 x16: 6c676e697320666f x15: 0000000000000001 x14: 1fffe0000d56d7ca x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 3e60944c3da92b00 x8 : 3e60944c3da92b00 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000898874f8 x4 : ffff800086ac99e0 x3 : ffff8000803f8808 x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000000 Call trace: packet_getname+0x25c/0x3a0 net/packet/af_packet.c:3604 __sys_getsockname+0x168/0x24c net/socket.c:2042 __do_sys_getsockname net/socket.c:2057 [inline] __se_sys_getsockname net/socket.c:2054 [inline] __arm64_sys_getsockname+0x7c/0x94 net/socket.c:2054 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x134/0x240 arch/arm64/kernel/syscall.c:139 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:188 el0_svc+0x2c/0x7c arch/arm64/kernel/entry-common.c:647 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:665 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 Fixes: df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3") Reported-by: syzkaller Suggested-by: Kees Cook Signed-off-by: Kuniyuki Iwashima Link: https://lore.kernel.org/r/20230724213425.22920-3-kuniyu@amazon.com Reviewed-by: Simon Horman Reviewed-by: Kees Cook Signed-off-by: Jakub Kicinski

net/packet: support mergeable feature of virtio

2023-04-21T11:01:58+00:00

Packet sockets, like tap, can be used as the backend for kernel vhost. In packet sockets, virtio net header size is currently hardcoded to be the size of struct virtio_net_hdr, which is 10 bytes; however, it is not always the case: some virtio features, such as mrg_rxbuf, need virtio net header to be 12-byte long. Mergeable buffers, as a virtio feature, is worthy of supporting: packets that are larger than one-mbuf size will be dropped in vhost worker's handle_rx if mrg_rxbuf feature is not used, but large packets cannot be avoided and increasing mbuf's size is not economical. With this virtio feature enabled by virtio-user, packet sockets with hardcoded 10-byte virtio net header will parse mac head incorrectly in packet_snd by taking the last two bytes of virtio net header as part of mac header. This incorrect mac header parsing will cause packet to be dropped due to invalid ether head checking in later under-layer device packet receiving. By adding extra field vnet_hdr_sz with utilizing holes in struct packet_sock to record currently used virtio net header size and supporting extra sockopt PACKET_VNET_HDR_SZ to set specified vnet_hdr_sz, packet sockets can know the exact length of virtio net header that virtio user gives. In packet_snd, tpacket_snd and packet_recvmsg, instead of using hardcoded virtio net header size, it can get the exact vnet_hdr_sz from corresponding packet_sock, and parse mac header correctly based on this information to avoid the packets being mistakenly dropped. Signed-off-by: Jianfeng Tan Co-developed-by: Anqi Shen Signed-off-by: Anqi Shen Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller

packet: add TP_STATUS_GSO_TCP for tp_status

2023-02-02T04:54:27+00:00

Introduce TP_STATUS_GSO_TCP tp_status flag to tell the af_packet user that this is a TCP GSO packet. When parsing IPv4 BIG TCP packets in tcpdump/libpcap, it can use tp_len as the IPv4 packet len when this flag is set, as iph tot_len is set to 0 for IPv4 BIG TCP packets. Signed-off-by: Xin Long Reviewed-by: David Ahern Reviewed-by: Eric Dumazet Signed-off-by: Jakub Kicinski

net/packet: add PACKET_FANOUT_FLAG_IGNORE_OUTGOING

2022-10-29T05:00:49+00:00

Extend packet socket option PACKET_IGNORE_OUTGOING to fanout groups. The socket option sets ptype.ignore_outgoing, which makes dev_queue_xmit_nit skip the socket. When the socket joins a fanout group, the option is not reflected in the struct ptype of the group. dev_queue_xmit_nit only tests the fanout ptype, so the flag is ignored once a socket joins a fanout group. Inheriting the option from a socket would change established behavior. Different sockets in the group can set different flags, and can also change them at runtime. Testing in packet_rcv_fanout defeats the purpose of the original patch, which is to avoid skb_clone in dev_queue_xmit_nit (esp. for MSG_ZEROCOPY packets). Instead, introduce a new fanout group flag with the same behavior. Tested with https://github.com/wdebruij/kerneltools/blob/master/tests/test_psock_fanout_ignore_outgoing.c Signed-off-by: Willem de Bruijn Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20221027211014.3581513-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski

net/packet: make packet_fanout.arr size configurable up to 64K

2020-11-10T00:41:40+00:00

One use case of PACKET_FANOUT is lockless reception with one socket per CPU. 256 is a practical limit on increasingly many machines. Increase PACKET_FANOUT_MAX to 64K. Expand setsockopt PACKET_FANOUT to take an extra argument max_num_members. Also explicitly define a fanout_args struct, instead of implicitly casting to an integer. This documents the API and simplifies the control flow. If max_num_members is not specified or is set to 0, then 256 is used, same as before. Signed-off-by: Tanner Love Signed-off-by: Willem de Bruijn Reviewed-by: Eric Dumazet Signed-off-by: Jakub Kicinski

packet: Fix undefined behavior in bit shift

2019-06-29T18:06:17+00:00

Shifting signed 32-bit value by 31 bits is undefined. Changing most significant bit to unsigned. Changes included in v2: - use subsystem specific subject lines - CC required mailing lists Signed-off-by: Jiunn Chang Signed-off-by: David S. Miller

packet: add sockopt to ignore outgoing packets

2018-09-06T05:09:37+00:00

Currently, the only way to ignore outgoing packets on a packet socket is via the BPF filter. With MSG_ZEROCOPY, packets that are looped into AF_PACKET are copied in dev_queue_xmit_nit(), and this copy happens even if the filter run from packet_rcv() would reject them. So the presence of a packet socket on the interface takes away the benefits of MSG_ZEROCOPY, even if the packet socket is not interested in outgoing packets. (Even when MSG_ZEROCOPY is not used, the skb is unnecessarily cloned, but the cost for that is much lower.) Add a socket option to allow AF_PACKET sockets to ignore outgoing packets to solve this. Note that the *BSDs already have something similar: BIOCSSEESENT/BIOCSDIRECTION and BIOCSDIRFILT. The first intended user is lldpd. Signed-off-by: Vincent Whitchurch Signed-off-by: David S. Miller

License cleanup: add SPDX license identifier to uapi header files with no license

2017-11-02T10:19:54+00:00

Many user space API headers are missing licensing information, which makes it hard for compliance tools to determine the correct license. By default are files without license information under the default license of the kernel, which is GPLV2. Marking them GPLV2 would exclude them from being included in non GPLV2 code, which is obviously not intended. The user space API headers fall under the syscall exception which is in the kernels COPYING file: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". otherwise syscall usage would not be possible. Update the files which contain no license information with an SPDX license identifier. The chosen identifier is 'GPL-2.0 WITH Linux-syscall-note' which is the officially assigned identifier for the Linux syscall exception. SPDX license identifiers are a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. See the previous patch in this series for the methodology of how this patch was researched. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

packet: add PACKET_FANOUT_FLAG_UNIQUEID to assign new fanout group id.

2017-04-24T16:46:00+00:00

Fanout uses a per net global namespace. A process that intends to create a new fanout group can accidentally join an existing group. It is not possible to detect this. Add socket option PACKET_FANOUT_FLAG_UNIQUEID. When specified the supplied fanout group id must be set to 0, and the kernel chooses an id that is not already in use. This is an ephemeral flag so that other sockets can be added to this group using setsockopt, but NOT specifying this flag. The current getsockopt(..., PACKET_FANOUT, ...) can be used to retrieve the new group id. We assume that there are not a lot of fanout groups and that this is not a high frequency call. The method assigns ids starting at zero and increases until it finds an unused id. It keeps track of the last assigned id, and uses it as a starting point to find new ids. Signed-off-by: Mike Maloney Acked-by: Willem de Bruijn Signed-off-by: David S. Miller