4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Biggers ebiggers@google.com
[ Upstream commit d49baa7e12ee70c0a7b821d088a770c94c02e494 ]
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: 6812baabf24d ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/smc/smc_pnet.c | 71 +++++++++++++++++++++++++++++------------------------ 1 file changed, 40 insertions(+), 31 deletions(-)
--- a/net/smc/smc_pnet.c +++ b/net/smc/smc_pnet.c @@ -245,40 +245,45 @@ out: static int smc_pnet_fill_entry(struct net *net, struct smc_pnetentry *pnetelem, struct nlattr *tb[]) { - char *string, *ibname = NULL; - int rc = 0; + char *string, *ibname; + int rc;
memset(pnetelem, 0, sizeof(*pnetelem)); INIT_LIST_HEAD(&pnetelem->list); - if (tb[SMC_PNETID_NAME]) { - string = (char *)nla_data(tb[SMC_PNETID_NAME]); - if (!smc_pnetid_valid(string, pnetelem->pnet_name)) { - rc = -EINVAL; - goto error; - } - } - if (tb[SMC_PNETID_ETHNAME]) { - string = (char *)nla_data(tb[SMC_PNETID_ETHNAME]); - pnetelem->ndev = dev_get_by_name(net, string); - if (!pnetelem->ndev) - return -ENOENT; - } - if (tb[SMC_PNETID_IBNAME]) { - ibname = (char *)nla_data(tb[SMC_PNETID_IBNAME]); - ibname = strim(ibname); - pnetelem->smcibdev = smc_pnet_find_ib(ibname); - if (!pnetelem->smcibdev) { - rc = -ENOENT; - goto error; - } - } - if (tb[SMC_PNETID_IBPORT]) { - pnetelem->ib_port = nla_get_u8(tb[SMC_PNETID_IBPORT]); - if (pnetelem->ib_port > SMC_MAX_PORTS) { - rc = -EINVAL; - goto error; - } - } + + rc = -EINVAL; + if (!tb[SMC_PNETID_NAME]) + goto error; + string = (char *)nla_data(tb[SMC_PNETID_NAME]); + if (!smc_pnetid_valid(string, pnetelem->pnet_name)) + goto error; + + rc = -EINVAL; + if (!tb[SMC_PNETID_ETHNAME]) + goto error; + rc = -ENOENT; + string = (char *)nla_data(tb[SMC_PNETID_ETHNAME]); + pnetelem->ndev = dev_get_by_name(net, string); + if (!pnetelem->ndev) + goto error; + + rc = -EINVAL; + if (!tb[SMC_PNETID_IBNAME]) + goto error; + rc = -ENOENT; + ibname = (char *)nla_data(tb[SMC_PNETID_IBNAME]); + ibname = strim(ibname); + pnetelem->smcibdev = smc_pnet_find_ib(ibname); + if (!pnetelem->smcibdev) + goto error; + + rc = -EINVAL; + if (!tb[SMC_PNETID_IBPORT]) + goto error; + pnetelem->ib_port = nla_get_u8(tb[SMC_PNETID_IBPORT]); + if (pnetelem->ib_port < 1 || pnetelem->ib_port > SMC_MAX_PORTS) + goto error; + return 0;
error: @@ -307,6 +312,8 @@ static int smc_pnet_get(struct sk_buff * void *hdr; int rc;
+ if (!info->attrs[SMC_PNETID_NAME]) + return -EINVAL; pnetelem = smc_pnet_find_pnetid( (char *)nla_data(info->attrs[SMC_PNETID_NAME])); if (!pnetelem) @@ -359,6 +366,8 @@ static int smc_pnet_add(struct sk_buff *
static int smc_pnet_del(struct sk_buff *skb, struct genl_info *info) { + if (!info->attrs[SMC_PNETID_NAME]) + return -EINVAL; return smc_pnet_remove_by_pnetid( (char *)nla_data(info->attrs[SMC_PNETID_NAME])); }