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Commit a9027581 authored by Lorenzo Colitti's avatar Lorenzo Colitti
Browse files

Properly size response buffer in ifc_act_on_address 

Currently, any netlink error reported in ifc_act_on_address is
reported as EINVAL, because the receive buffer is too short and
the NLMSG_OK check fails on it.

Make the buffer long enough so the function can return the
correct netlink error to the caller.

Test: new test coverage in other CL in this topic
Change-Id: Ica752db834a0fd614312b800d88721826be08d56
parent c3d38969

libnetutils/ifc_utils.c

+4 −9
Original line number Diff line number Diff line
@@ -267,19 +267,13 @@ int ifc_act_on_address(int action, const char *name, const char *address, 
    struct {

        struct nlmsghdr n;

        struct ifaddrmsg r;

        // Allow for IPv6 address, headers, IPv4 broadcast addr and padding.

        char attrbuf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +

                     NLMSG_ALIGN(sizeof(struct rtattr)) +

                     NLMSG_ALIGN(INET6_ADDRLEN) +

                     NLMSG_ALIGN(sizeof(struct rtattr)) +

                     NLMSG_ALIGN(INET_ADDRLEN)];

        // Allow for IPv4 or IPv6 address, headers, IPv4 broadcast address and padding.

        char attrbuf[NLMSG_ALIGN(sizeof(struct rtattr)) + NLMSG_ALIGN(INET6_ADDRLEN) +

                     NLMSG_ALIGN(sizeof(struct rtattr)) + NLMSG_ALIGN(INET_ADDRLEN)];

    } req;

    struct rtattr *rta;

    struct nlmsghdr *nh;

    struct nlmsgerr *err;

    char buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +

             NLMSG_ALIGN(sizeof(struct nlmsgerr)) +

             NLMSG_ALIGN(sizeof(struct nlmsghdr))];



    // Get interface ID.

    ifindex = if_nametoindex(name);
@@ -348,6 +342,7 @@ int ifc_act_on_address(int action, const char *name, const char *address, 
        return -saved_errno;

    }



    char buf[NLMSG_ALIGN(sizeof(struct nlmsgerr)) + sizeof(req)];

    len = recv(s, buf, sizeof(buf), 0);

    saved_errno = errno;

    close(s);