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    Subject[PATCH 3.2 070/140] af_key: fix buffer overread in verify_address_len()
    3.2.100-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Eric Biggers <ebiggers@google.com>

    commit 06b335cb51af018d5feeff5dd4fd53847ddb675a upstream.

    If a message sent to a PF_KEY socket ended with one of the extensions
    that takes a 'struct sadb_address' but there were not enough bytes
    remaining in the message for the ->sa_family member of the 'struct
    sockaddr' which is supposed to follow, then verify_address_len() read
    past the end of the message, into uninitialized memory. Fix it by
    returning -EINVAL in this case.

    This bug was found using syzkaller with KMSAN.

    Reproducer:

    #include <linux/pfkeyv2.h>
    #include <sys/socket.h>
    #include <unistd.h>

    int main()
    {
    int sock = socket(PF_KEY, SOCK_RAW, PF_KEY_V2);
    char buf[24] = { 0 };
    struct sadb_msg *msg = (void *)buf;
    struct sadb_address *addr = (void *)(msg + 1);

    msg->sadb_msg_version = PF_KEY_V2;
    msg->sadb_msg_type = SADB_DELETE;
    msg->sadb_msg_len = 3;
    addr->sadb_address_len = 1;
    addr->sadb_address_exttype = SADB_EXT_ADDRESS_SRC;

    write(sock, buf, 24);
    }

    Reported-by: Alexander Potapenko <glider@google.com>
    Signed-off-by: Eric Biggers <ebiggers@google.com>
    Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    net/key/af_key.c | 5 +++++
    1 file changed, 5 insertions(+)

    --- a/net/key/af_key.c
    +++ b/net/key/af_key.c
    @@ -398,6 +398,11 @@ static int verify_address_len(const void
    #endif
    int len;

    + if (sp->sadb_address_len <
    + DIV_ROUND_UP(sizeof(*sp) + offsetofend(typeof(*addr), sa_family),
    + sizeof(uint64_t)))
    + return -EINVAL;
    +
    switch (addr->sa_family) {
    case AF_INET:
    len = DIV_ROUND_UP(sizeof(*sp) + sizeof(*sin), sizeof(uint64_t));
    \
     
     \ /
      Last update: 2018-02-28 18:24    [W:4.214 / U:0.052 seconds]
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