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authorKlement Sekera <ksekera@cisco.com>2018-12-10 13:46:09 +0100
committerDave Barach <openvpp@barachs.net>2018-12-13 14:42:50 +0000
commit14d7e90788f87a4b7b174bb5a67171f8c9a7f842 (patch)
treee89f6b874b29d9d20ea243a635728cacc4d2d85d /src
parent69db1a60846f3e7dea3e1f615c396c356a49532e (diff)
VPP-1522: harden reassembly code
Change-Id: Ib5a20bff7d8a340ecf50bcd4a023d6bf36382ba3 Signed-off-by: Klement Sekera <ksekera@cisco.com>
Diffstat (limited to 'src')
-rw-r--r--src/vnet/ip/ip4_error.h3
-rw-r--r--src/vnet/ip/ip4_reassembly.c61
2 files changed, 40 insertions, 24 deletions
diff --git a/src/vnet/ip/ip4_error.h b/src/vnet/ip/ip4_error.h
index 52c43adb12c..15828e39ac5 100644
--- a/src/vnet/ip/ip4_error.h
+++ b/src/vnet/ip/ip4_error.h
@@ -86,7 +86,8 @@
/* Errors signalled by ip4-reassembly */ \
_ (REASS_DUPLICATE_FRAGMENT, "duplicate/overlapping fragments") \
_ (REASS_LIMIT_REACHED, "drops due to concurrent reassemblies limit") \
- _ (REASS_TIMEOUT, "fragments dropped due to reassembly timeout")
+ _ (REASS_TIMEOUT, "fragments dropped due to reassembly timeout") \
+ _ (REASS_MALFORMED_PACKET, "malformed packets")
typedef enum
{
diff --git a/src/vnet/ip/ip4_reassembly.c b/src/vnet/ip/ip4_reassembly.c
index bd33026db85..9bcc20a2285 100644
--- a/src/vnet/ip/ip4_reassembly.c
+++ b/src/vnet/ip/ip4_reassembly.c
@@ -654,12 +654,12 @@ ip4_reass_update (vlib_main_t * vm, vlib_node_runtime_t * node,
ASSERT (fb->current_length >= sizeof (*fip));
vnet_buffer_opaque_t *fvnb = vnet_buffer (fb);
reass->next_index = fvnb->ip.reass.next_index; // store next_index before it's overwritten
- u32 fragment_first = fvnb->ip.reass.fragment_first =
- ip4_get_fragment_offset_bytes (fip);
- u32 fragment_length =
+ const u32 fragment_first = ip4_get_fragment_offset_bytes (fip);
+ const u32 fragment_length =
clib_net_to_host_u16 (fip->length) - ip4_header_bytes (fip);
- u32 fragment_last = fvnb->ip.reass.fragment_last =
- fragment_first + fragment_length - 1;
+ const u32 fragment_last = fragment_first + fragment_length - 1;
+ fvnb->ip.reass.fragment_first = fragment_first;
+ fvnb->ip.reass.fragment_last = fragment_last;
int more_fragments = ip4_get_fragment_more (fip);
u32 candidate_range_bi = reass->first_bi;
u32 prev_range_bi = ~0;
@@ -927,28 +927,43 @@ ip4_reassembly_inline (vlib_main_t * vm,
}
else
{
- ip4_reass_key_t k;
- k.as_u64[0] =
- (u64) vnet_buffer (b0)->sw_if_index[VLIB_RX] << 32 | (u64)
- ip0->src_address.as_u32;
- k.as_u64[1] =
- (u64) ip0->dst_address.
- as_u32 << 32 | (u64) ip0->fragment_id << 16 | (u64) ip0->
- protocol << 8;
-
- ip4_reass_t *reass =
- ip4_reass_find_or_create (vm, rm, rt, &k, &vec_drop_timeout);
-
- if (reass)
+ ip4_header_t *fip = vlib_buffer_get_current (b0);
+ const u32 fragment_first = ip4_get_fragment_offset_bytes (fip);
+ const u32 fragment_length =
+ clib_net_to_host_u16 (fip->length) - ip4_header_bytes (fip);
+ const u32 fragment_last = fragment_first + fragment_length - 1;
+ if (fragment_first > fragment_last
+ || fragment_first + fragment_length > UINT16_MAX - 20)
{
- ip4_reass_update (vm, node, rm, rt, reass, &bi0, &next0,
- &error0, &vec_drop_overlap,
- &vec_drop_compress, is_feature);
+ next0 = IP4_REASSEMBLY_NEXT_DROP;
+ error0 = IP4_ERROR_REASS_MALFORMED_PACKET;
}
else
{
- next0 = IP4_REASSEMBLY_NEXT_DROP;
- error0 = IP4_ERROR_REASS_LIMIT_REACHED;
+ ip4_reass_key_t k;
+ k.as_u64[0] =
+ (u64) vnet_buffer (b0)->sw_if_index[VLIB_RX] << 32 | (u64)
+ ip0->src_address.as_u32;
+ k.as_u64[1] =
+ (u64) ip0->dst_address.
+ as_u32 << 32 | (u64) ip0->fragment_id << 16 | (u64) ip0->
+ protocol << 8;
+
+ ip4_reass_t *reass =
+ ip4_reass_find_or_create (vm, rm, rt, &k,
+ &vec_drop_timeout);
+
+ if (reass)
+ {
+ ip4_reass_update (vm, node, rm, rt, reass, &bi0, &next0,
+ &error0, &vec_drop_overlap,
+ &vec_drop_compress, is_feature);
+ }
+ else
+ {
+ next0 = IP4_REASSEMBLY_NEXT_DROP;
+ error0 = IP4_ERROR_REASS_LIMIT_REACHED;
+ }
}
b0->error = node->errors[error0];