It's possible to crash the kernel in several different ways by sending
messages to the SMC_PNETID generic netlink family that are missing the
expected attributes:
- Missing SMC_PNETID_NAME => null pointer dereference when comparing
names.
- Missing SMC_PNETID_ETHNAME => null pointer dereference accessing
smc_pnetentry::ndev.
- Missing SMC_PNETID_IBNAME => null pointer dereference accessing
smc_pnetentry::smcibdev.
- Missing SMC_PNETID_IBPORT => out of bounds array access to
smc_ib_device::pattr[-1].
Fix it by validating that all expected attributes are present and that
SMC_PNETID_IBPORT is nonzero.
Reported-by: syzbot+5cd61039dc9b8bfa6e47@syzkaller.appspotmail.com
Fixes: 6812baabf2 ("smc: establish pnet table management")
Cc: <stable@vger.kernel.org> # v4.11+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
d49baa7e12