linux-toradex.git/net/ipv4/ip_options.c, branch v3.2.74

ipv4: fix buffer overflow in ip_options_compile()

2014-08-06T17:07:39+00:00

[ Upstream commit 10ec9472f05b45c94db3c854d22581a20b97db41 ]

There is a benign buffer overflow in ip_options_compile spotted by
AddressSanitizer[1] :

Its benign because we always can access one extra byte in skb->head
(because header is followed by struct skb_shared_info), and in this case
this byte is not even used.

[28504.910798] ==================================================================
[28504.912046] AddressSanitizer: heap-buffer-overflow in ip_options_compile
[28504.913170] Read of size 1 by thread T15843:
[28504.914026]  [] ip_options_compile+0x121/0x9c0
[28504.915394]  [] ip_options_get_from_user+0xad/0x120
[28504.916843]  [] do_ip_setsockopt.isra.15+0x8df/0x1630
[28504.918175]  [] ip_setsockopt+0x30/0xa0
[28504.919490]  [] tcp_setsockopt+0x5b/0x90
[28504.920835]  [] sock_common_setsockopt+0x5f/0x70
[28504.922208]  [] SyS_setsockopt+0xa2/0x140
[28504.923459]  [] system_call_fastpath+0x16/0x1b
[28504.924722]
[28504.925106] Allocated by thread T15843:
[28504.925815]  [] ip_options_get_from_user+0x35/0x120
[28504.926884]  [] do_ip_setsockopt.isra.15+0x8df/0x1630
[28504.927975]  [] ip_setsockopt+0x30/0xa0
[28504.929175]  [] tcp_setsockopt+0x5b/0x90
[28504.930400]  [] sock_common_setsockopt+0x5f/0x70
[28504.931677]  [] SyS_setsockopt+0xa2/0x140
[28504.932851]  [] system_call_fastpath+0x16/0x1b
[28504.934018]
[28504.934377] The buggy address ffff880026382828 is located 0 bytes to the right
[28504.934377]  of 40-byte region [ffff880026382800, ffff880026382828)
[28504.937144]
[28504.937474] Memory state around the buggy address:
[28504.938430]  ffff880026382300: ........ rrrrrrrr rrrrrrrr rrrrrrrr
[28504.939884]  ffff880026382400: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr
[28504.941294]  ffff880026382500: .....rrr rrrrrrrr rrrrrrrr rrrrrrrr
[28504.942504]  ffff880026382600: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr
[28504.943483]  ffff880026382700: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr
[28504.944511] >ffff880026382800: .....rrr rrrrrrrr rrrrrrrr rrrrrrrr
[28504.945573]                         ^
[28504.946277]  ffff880026382900: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr
[28505.094949]  ffff880026382a00: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr
[28505.096114]  ffff880026382b00: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr
[28505.097116]  ffff880026382c00: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr
[28505.098472]  ffff880026382d00: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr
[28505.099804] Legend:
[28505.100269]  f - 8 freed bytes
[28505.100884]  r - 8 redzone bytes
[28505.101649]  . - 8 allocated bytes
[28505.102406]  x=1..7 - x allocated bytes + (8-x) redzone bytes
[28505.103637] ==================================================================

[1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

net/ipv4: Ensure that location of timestamp option is stored

2013-03-27T02:41:04+00:00

[ Upstream commit 4660c7f498c07c43173142ea95145e9dac5a6d14 ]

This is needed in order to detect if the timestamp option appears
more than once in a packet, to remove the option if the packet is
fragmented, etc. My previous change neglected to store the option
location when the router addresses were prespecified and Pointer >
Length. But now the option location is also stored when Flag is an
unrecognized value, to ensure these option handling behaviors are
still performed.

Signed-off-by: David Ward 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv4: Fix wrong order of ip_rt_get_source() and update iph->daddr.

2012-03-01T00:31:02+00:00

[ Upstream commit 5dc7883f2a7c25f8df40d7479687153558cd531b ]

This patch fix a bug which introduced by commit ac8a4810 (ipv4: Save
nexthop address of LSRR/SSRR option to IPCB.).In that patch, we saved
the nexthop of SRR in ip_option->nexthop and update iph->daddr until
we get to ip_forward_options(), but we need to update it before
ip_rt_get_source(), otherwise we may get a wrong src.

Signed-off-by: Li Wei 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: Save nexthop address of LSRR/SSRR option to IPCB.

2011-11-24T00:19:32+00:00

We can not update iph->daddr in ip_options_rcv_srr(), It is too early.
When some exception ocurred later (eg. in ip_forward() when goto
sr_failed) we need the ip header be identical to the original one as
ICMP need it.

Add a field 'nexthop' in struct ip_options to save nexthop of LSRR
or SSRR option.

Signed-off-by: Li Wei 
Signed-off-by: David S. Miller

ipv4: fix for ip_options_rcv_srr() daddr update.

2011-11-09T20:59:00+00:00

When opt->srr_is_hit is set skb_rtable(skb) has been updated for
'nexthop' and iph->daddr should always equals to skb_rtable->rt_dst
holds, We need update iph->daddr either.

Signed-off-by: Li Wei 
Signed-off-by: David S. Miller

ip_options_compile: properly handle unaligned pointer

2011-05-31T22:11:02+00:00

The current code takes an unaligned pointer and does htonl() on it to
make it big-endian, then does a memcpy().  The problem is that the
compiler decides that since the pointer is to a __be32, it is legal
to optimize the copy into a processor word store.  However, on an
architecture that does not handled unaligned writes in kernel space,
this produces an unaligned exception fault.

The solution is to track the pointer as a "char *" (which removes a bunch
of unpleasant casts in any case), and then just use put_unaligned_be32()
to write the value to memory.

Signed-off-by: Chris Metcalf 
Signed-off-by: David S. Miller

ipv4: Remove rt->rt_dst reference from ip_forward_options().

2011-05-13T21:31:02+00:00

At this point iph->daddr equals what rt->rt_dst would hold.

Signed-off-by: David S. Miller

ipv4: Remove route key identity dependencies in ip_rt_get_source().

2011-05-13T21:29:41+00:00

Pass in the sk_buff so that we can fetch the necessary keys from
the packet header when working with input routes.

Signed-off-by: David S. Miller

ipv4: Kill spurious write to iph->daddr in ip_forward_options().

2011-05-13T21:15:50+00:00

This code block executes when opt->srr_is_hit is set.  It will be
set only by ip_options_rcv_srr().

ip_options_rcv_srr() walks until it hits a matching nexthop in the SRR
option addresses, and when it matches one 1) looks up the route for
that nexthop and 2) on route lookup success it writes that nexthop
value into iph->daddr.

ip_forward_options() runs later, and again walks the SRR option
addresses looking for the option matching the destination of the route
stored in skb_rtable().  This route will be the same exact one looked
up for the nexthop by ip_options_rcv_srr().

Therefore "rt->rt_dst == iph->daddr" must be true.

All it really needs to do is record the route's source address in the
matching SRR option adddress.  It need not write iph->daddr again,
since that has already been done by ip_options_rcv_srr() as detailed
above.

Signed-off-by: David S. Miller

ipv4: Simplify iph->daddr overwrite in ip_options_rcv_srr().

2011-05-12T23:30:58+00:00

We already copy the 4-byte nexthop from the options block into
local variable "nexthop" for the route lookup.

Re-use that variable instead of memcpy()'ing again when assigning
to iph->daddr after the route lookup succeeds.

Signed-off-by: David S. Miller