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    Subject[PATCH 4.4 23/23] sctp: validate from_addr_param return
    Date
    From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

    commit 0c5dc070ff3d6246d22ddd931f23a6266249e3db upstream.

    Ilja reported that, simply putting it, nothing was validating that
    from_addr_param functions were operating on initialized memory. That is,
    the parameter itself was being validated by sctp_walk_params, but it
    doesn't check for types and their specific sizes and it could be a 0-length
    one, causing from_addr_param to potentially work over the next parameter or
    even uninitialized memory.

    The fix here is to, in all calls to from_addr_param, check if enough space
    is there for the wanted IP address type.

    Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
    Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    include/net/sctp/structs.h | 2 +-
    net/sctp/bind_addr.c | 20 +++++++++++---------
    net/sctp/input.c | 6 ++++--
    net/sctp/ipv6.c | 7 ++++++-
    net/sctp/protocol.c | 7 ++++++-
    net/sctp/sm_make_chunk.c | 29 ++++++++++++++++-------------
    6 files changed, 44 insertions(+), 27 deletions(-)

    --- a/include/net/sctp/structs.h
    +++ b/include/net/sctp/structs.h
    @@ -469,7 +469,7 @@ struct sctp_af {
    int saddr);
    void (*from_sk) (union sctp_addr *,
    struct sock *sk);
    - void (*from_addr_param) (union sctp_addr *,
    + bool (*from_addr_param) (union sctp_addr *,
    union sctp_addr_param *,
    __be16 port, int iif);
    int (*to_addr_param) (const union sctp_addr *,
    --- a/net/sctp/bind_addr.c
    +++ b/net/sctp/bind_addr.c
    @@ -284,19 +284,15 @@ int sctp_raw_to_bind_addrs(struct sctp_b
    rawaddr = (union sctp_addr_param *)raw_addr_list;

    af = sctp_get_af_specific(param_type2af(param->type));
    - if (unlikely(!af)) {
    + if (unlikely(!af) ||
    + !af->from_addr_param(&addr, rawaddr, htons(port), 0)) {
    retval = -EINVAL;
    - sctp_bind_addr_clean(bp);
    - break;
    + goto out_err;
    }

    - af->from_addr_param(&addr, rawaddr, htons(port), 0);
    retval = sctp_add_bind_addr(bp, &addr, SCTP_ADDR_SRC, gfp);
    - if (retval) {
    - /* Can't finish building the list, clean up. */
    - sctp_bind_addr_clean(bp);
    - break;
    - }
    + if (retval)
    + goto out_err;

    len = ntohs(param->length);
    addrs_len -= len;
    @@ -304,6 +300,12 @@ int sctp_raw_to_bind_addrs(struct sctp_b
    }

    return retval;
    +
    +out_err:
    + if (retval)
    + sctp_bind_addr_clean(bp);
    +
    + return retval;
    }

    /********************************************************************
    --- a/net/sctp/input.c
    +++ b/net/sctp/input.c
    @@ -972,7 +972,8 @@ static struct sctp_association *__sctp_r
    if (!af)
    continue;

    - af->from_addr_param(paddr, params.addr, sh->source, 0);
    + if (!af->from_addr_param(paddr, params.addr, sh->source, 0))
    + continue;

    asoc = __sctp_lookup_association(net, laddr, paddr, &transport);
    if (asoc)
    @@ -1018,7 +1019,8 @@ static struct sctp_association *__sctp_r
    if (unlikely(!af))
    return NULL;

    - af->from_addr_param(&paddr, param, peer_port, 0);
    + if (af->from_addr_param(&paddr, param, peer_port, 0))
    + return NULL;

    return __sctp_lookup_association(net, laddr, &paddr, transportp);
    }
    --- a/net/sctp/ipv6.c
    +++ b/net/sctp/ipv6.c
    @@ -488,15 +488,20 @@ static void sctp_v6_to_sk_daddr(union sc
    }

    /* Initialize a sctp_addr from an address parameter. */
    -static void sctp_v6_from_addr_param(union sctp_addr *addr,
    +static bool sctp_v6_from_addr_param(union sctp_addr *addr,
    union sctp_addr_param *param,
    __be16 port, int iif)
    {
    + if (ntohs(param->v6.param_hdr.length) < sizeof(struct sctp_ipv6addr_param))
    + return false;
    +
    addr->v6.sin6_family = AF_INET6;
    addr->v6.sin6_port = port;
    addr->v6.sin6_flowinfo = 0; /* BUG */
    addr->v6.sin6_addr = param->v6.addr;
    addr->v6.sin6_scope_id = iif;
    +
    + return true;
    }

    /* Initialize an address parameter from a sctp_addr and return the length
    --- a/net/sctp/protocol.c
    +++ b/net/sctp/protocol.c
    @@ -272,14 +272,19 @@ static void sctp_v4_to_sk_daddr(union sc
    }

    /* Initialize a sctp_addr from an address parameter. */
    -static void sctp_v4_from_addr_param(union sctp_addr *addr,
    +static bool sctp_v4_from_addr_param(union sctp_addr *addr,
    union sctp_addr_param *param,
    __be16 port, int iif)
    {
    + if (ntohs(param->v4.param_hdr.length) < sizeof(struct sctp_ipv4addr_param))
    + return false;
    +
    addr->v4.sin_family = AF_INET;
    addr->v4.sin_port = port;
    addr->v4.sin_addr.s_addr = param->v4.addr.s_addr;
    memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
    +
    + return true;
    }

    /* Initialize an address parameter from a sctp_addr and return the length
    --- a/net/sctp/sm_make_chunk.c
    +++ b/net/sctp/sm_make_chunk.c
    @@ -2333,11 +2333,13 @@ int sctp_process_init(struct sctp_associ

    /* Process the initialization parameters. */
    sctp_walk_params(param, peer_init, init_hdr.params) {
    - if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
    - param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
    + if (!src_match &&
    + (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
    + param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
    af = sctp_get_af_specific(param_type2af(param.p->type));
    - af->from_addr_param(&addr, param.addr,
    - chunk->sctp_hdr->source, 0);
    + if (!af->from_addr_param(&addr, param.addr,
    + chunk->sctp_hdr->source, 0))
    + continue;
    if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
    src_match = 1;
    }
    @@ -2531,7 +2533,8 @@ static int sctp_process_param(struct sct
    break;
    do_addr_param:
    af = sctp_get_af_specific(param_type2af(param.p->type));
    - af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
    + if (!af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0))
    + break;
    scope = sctp_scope(peer_addr);
    if (sctp_in_scope(net, &addr, scope))
    if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
    @@ -2624,15 +2627,13 @@ do_addr_param:
    addr_param = param.v + sizeof(sctp_addip_param_t);

    af = sctp_get_af_specific(param_type2af(addr_param->p.type));
    - if (af == NULL)
    + if (!af)
    break;

    - af->from_addr_param(&addr, addr_param,
    - htons(asoc->peer.port), 0);
    + if (!af->from_addr_param(&addr, addr_param,
    + htons(asoc->peer.port), 0))
    + break;

    - /* if the address is invalid, we can't process it.
    - * XXX: see spec for what to do.
    - */
    if (!af->addr_valid(&addr, NULL, NULL))
    break;

    @@ -3042,7 +3043,8 @@ static __be16 sctp_process_asconf_param(
    if (unlikely(!af))
    return SCTP_ERROR_DNS_FAILED;

    - af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
    + if (!af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0))
    + return SCTP_ERROR_DNS_FAILED;

    /* ADDIP 4.2.1 This parameter MUST NOT contain a broadcast
    * or multicast address.
    @@ -3308,7 +3310,8 @@ static void sctp_asconf_param_success(st

    /* We have checked the packet before, so we do not check again. */
    af = sctp_get_af_specific(param_type2af(addr_param->p.type));
    - af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
    + if (!af->from_addr_param(&addr, addr_param, htons(bp->port), 0))
    + return;

    switch (asconf_param->param_hdr.type) {
    case SCTP_PARAM_ADD_IP:

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