From ac1a1de31515d950f858ba47d2bba74ff9a2614d Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Thu, 24 Nov 2011 23:08:49 +0000 Subject: NET: NETROM: When adding a route verify length of mnemonic string. struct nr_route_struct's mnemonic permits a string of up to 7 bytes to be used. If userland passes a not zero terminated string to the kernel adding a node to the routing table might result in the kernel attempting to read copy a too long string. Mnemonic is part of the NET/ROM routing protocol; NET/ROM routing table updates only broadcast 6 bytes. The 7th byte in the mnemonic array exists only as a \0 termination character for the kernel code's convenience. Fixed by rejecting mnemonic strings that have no terminating \0 in the first 7 characters. Do this test only NETROM_NODE to avoid breaking NETROM_NEIGH where userland might passing an uninitialized mnemonic field. Initial patch by Dan Carpenter . Signed-off-by: Ralf Baechle Cc: Dan Carpenter Cc: Walter Harms Cc: Thomas Osterried Acked-by: Dan Carpenter Signed-off-by: David S. Miller --- net/netrom/nr_route.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'net/netrom/nr_route.c') diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c index 915a87ba23e1..8d7716ca5342 100644 --- a/net/netrom/nr_route.c +++ b/net/netrom/nr_route.c @@ -678,6 +678,11 @@ int nr_rt_ioctl(unsigned int cmd, void __user *arg) } switch (nr_route.type) { case NETROM_NODE: + if (strnlen(nr_route.mnemonic, 7) == 7) { + ret = -EINVAL; + break; + } + ret = nr_add_node(&nr_route.callsign, nr_route.mnemonic, &nr_route.neighbour, -- cgit v1.2.3 From 10cae1c8dfbbdee55bdfcb7034f4c2c1197dc0a4 Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Thu, 24 Nov 2011 23:09:00 +0000 Subject: NET: NETROM: Cleanup argument SIOCADDRT ioctl argument checking. nr_route.ndigis is unsigned int so the nr_route.ndigis < 0 expression is never true and can be dropped. Doing the nr_ax25_dev_get call later allows the nr_route.ndigis test to bail out without having to dev_put. Signed-off-by: Ralf Baechle Cc: Thomas Osterried Signed-off-by: David S. Miller --- net/netrom/nr_route.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'net/netrom/nr_route.c') diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c index 8d7716ca5342..2cf330162d7e 100644 --- a/net/netrom/nr_route.c +++ b/net/netrom/nr_route.c @@ -670,12 +670,10 @@ int nr_rt_ioctl(unsigned int cmd, void __user *arg) case SIOCADDRT: if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct))) return -EFAULT; - if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL) + if (nr_route.ndigis > AX25_MAX_DIGIS) return -EINVAL; - if (nr_route.ndigis < 0 || nr_route.ndigis > AX25_MAX_DIGIS) { - dev_put(dev); + if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL) return -EINVAL; - } switch (nr_route.type) { case NETROM_NODE: if (strnlen(nr_route.mnemonic, 7) == 7) { -- cgit v1.2.3