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* pasta: do not leak netlink sock into childPaul Holzinger2023-02-121-2/+2
| | | | | | | | | | | | | | When spawning a child command with pasta command... pasta should not leak fds that it opened. Only the fds that were already open should be given to the child. Run `pasta --config-net -- ls -l /proc/self/fd` from a terminal where only stdin/out/err are open. The fd 3 was opend by ls to read the /proc/self/fd dir. But fd 5 is the netlink socket that was opend in pasta. To prevent such a leak we will open the socket with SOCK_CLOEXEC. Signed-off-by: Paul Holzinger <pholzing@redhat.com> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf: Bind inbound ports with CAP_NET_BIND_SERVICE before isolate_user()Stefano Brivio2022-10-151-19/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Even if CAP_NET_BIND_SERVICE is granted, we'll lose the capability in the target user namespace as we isolate the process, which means we're unable to bind to low ports at that point. Bind inbound ports, and only those, before isolate_user(). Keep the handling of outbound ports (for pasta mode only) after the setup of the namespace, because that's where we'll bind them. To this end, initialise the netlink socket for the init namespace before isolate_user() as well, as we actually need to know the addresses of the upstream interface before binding ports, in case they're not explicitly passed by the user. As we now call nl_sock_init() twice, checking its return code from conf() twice looks a bit heavy: make it exit(), instead, as we can't do much if we don't have netlink sockets. While at it: - move the v4_only && v6_only options check just after the first option processing loop, as this is more strictly related to option parsing proper - update the man page, explaining that CAP_NET_BIND_SERVICE is *not* the preferred way to bind ports, because passt and pasta can be abused to allow other processes to make effective usage of it. Add a note about the recommended sysctl instead - simplify nl_sock_init_do() now that it's called once for each case Reported-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* netlink: Disable duplicate address detection for configured IPv6 addressStefano Brivio2022-10-151-0/+3
| | | | | | | | | | | | | | | | | | With default options, when we pass --config-net, the IPv6 address is actually going to be recycled from the init namespace, so it is in fact duplicated, but duplicate address detection has no way to find out. With a different configured address, that's not the case, but anyway duplicate address detection will be unable to see this. In both cases, we're wasting time for nothing. Pass the IFA_F_NODAD flag as we configure globally scoped IPv6 addresses via netlink. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* Move logging functions to a new file, log.cStefano Brivio2022-10-141-0/+1
| | | | | | | | Logging to file is going to add some further complexity that we don't want to squeeze into util.c. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
* Avoid ugly 'end' members in netlink structuresDavid Gibson2022-09-291-9/+10
| | | | | | | | | | | | | | We use a number of complex structures to format messages to send to netlink. In some cases we add imaginary 'end' members not because they actually mean something on the wire, but so that we can use offsetof() on the member to determine the relevant size. Adding extra things to the structures for this is kinda nasty. We can use a different construct with offsetof and sizeof to avoid them. As a bonus this removes some cppcheck warnings about unused struct members. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* cppcheck: Reduce scope of some variablesDavid Gibson2022-09-291-2/+1
| | | | | | | Minor style improvement suggested by cppcheck. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* Separately locate external interfaces for IPv4 and IPv6David Gibson2022-07-301-72/+7
| | | | | | | | | | | | | | | | | Now that the back end allows passt/pasta to use different external interfaces for IPv4 and IPv6, use that to do the right thing in the case that the host has IPv4 and IPv6 connectivity via different interfaces. If the user hasn't explicitly chosen an interface, separately search for a suitable external interface for each protocol. As a bonus, this substantially simplifies the external interface probe. It also eliminates a subtle confusing case where in some circumstances we would pick the first interface in interface index order, and sometimes in order of routes returned from netlink. On some network configurations that could cause tests to fail, because the logic in the tests was subtly different (it always used route order). Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* netlink: In nl_addr() and nl_route(), don't return before set requestStefano Brivio2022-05-011-2/+2
| | | | | Fixes: 22ed4467a413 ("treewide: Unchecked return value from library, CWE-252") Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* treewide: Unchecked return value from library, CWE-252Stefano Brivio2022-04-071-15/+25
| | | | | | | All instances were harmless, but it might be useful to have some debug messages here and there. Reported by Coverity. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* treewide: Mark constant references as constStefano Brivio2022-03-291-2/+2
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* netlink: Avoid left-over bytes in request on MTU configurationStefano Brivio2022-02-231-4/+7
| | | | | | | | | When nl_link() configures the MTU, it shouldn't send extra bytes, otherwise we'll get a kernel warning: netlink: 4 bytes leftover after parsing attributes in process `pasta'. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* netlink: Fix swapped v4/v6-only flags in external interface detectionStefano Brivio2022-01-261-2/+2
| | | | | | | The effect of this typo became visible in an IPv6-only environment, where passt wouldn't work at all. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* tcp, netlink, HAS{BYTES_ACKED,MIN_RTT,GETRANDOM} and NETLINK_GET_STRICT_CHKStefano Brivio2022-01-261-2/+7
| | | | | | | | | | | | | | | | tcpi_bytes_acked and tcpi_min_rtt are only available on recent kernel versions: provide fall-back paths (incurring some grade of performance penalty). Support for getrandom() was introduced in Linux 3.17 and glibc 2.25: provide an alternate mechanism for that as well, reading from /dev/random. Also check if NETLINK_GET_STRICT_CHK is defined before using it: it's not strictly needed, we'll filter out irrelevant results from netlink anyway. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Drop <linux/ipv6.h> include, carry own ipv6hdr and opt_hdr definitionsStefano Brivio2022-01-261-1/+0
| | | | | | | This is the only remaining Linux-specific include -- drop it to avoid clang-tidy warnings and to make code more portable. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* netlink: Fix length of address attributeStefano Brivio2021-10-211-2/+2
| | | | | | | | ...I broke this while playing with clang-tidy, and didn't add tests for pasta's --config-net yet. Reported-by: Giuseppe Scrivano <gscrivan@redhat.com> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Add cppcheck target, test, and address resulting warningsStefano Brivio2021-10-211-5/+3
| | | | | | | ...mostly false positives, but a number of very relevant ones too, in tcp_get_sndbuf(), tcp_conn_from_tap(), and siphash PREAMBLE(). Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Fix build with gcc 7, use std=c99, enable some more Clang checkersStefano Brivio2021-10-211-36/+45
| | | | | | | | | | | | | | Unions and structs, you all have names now. Take the chance to enable bugprone-reserved-identifier, cert-dcl37-c, and cert-dcl51-cpp checkers in clang-tidy. Provide a ffsl() weak declaration using gcc built-in. Start reordering includes, but that's not enough for the llvm-include-order checker yet. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* passt: Add clang-tidy Makefile target and test, take care of warningsStefano Brivio2021-10-201-15/+18
| | | | | | | Most are just about style and form, but a few were actually serious mistakes (NDP-related). Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* netlink: NETLINK_GET_STRICT_CHK is not available on older kernelsStefano Brivio2021-10-191-3/+6
| | | | | | | For example on 4.19. Don't fail if we can't set it, filter on interface index in nl_addr(). Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* netlink, conf: Actually get prefix/mask lengthStefano Brivio2021-10-191-5/+8
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* netlink: Bring up interface even if neither MTU nor MAC address is configuredStefano Brivio2021-10-141-0/+5
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* netlink, pasta: Configure MTU of tap interface on --config-netStefano Brivio2021-10-141-16/+28
| | | | Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* conf, tap: Split netlink and pasta functions, allow interface configurationStefano Brivio2021-10-141-0/+514
Move netlink routines to their own file, and use netlink to configure or fetch all the information we need, except for the TUNSETIFF ioctl. Move pasta-specific functions to their own file as well, add parameters and calls to configure the tap interface in the namespace. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
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