[ovs-dev,v1] conntrack: Fix ICMPV4 error data L4 length check.
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Message ID 1566835595-72476-1-git-send-email-dlu998@gmail.com
State New
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Series
  • [ovs-dev,v1] conntrack: Fix ICMPV4 error data L4 length check.
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Commit Message

Darrell Ball Aug. 26, 2019, 4:06 p.m. UTC
The ICMP error data L4 length check was found to be too strict for TCP,
expecting a minimum of 20 rather than 8 bytes.  This worked by
hapenstance for other inner protocols.  The approach is to explicitly
handle the ICMPV4 error data L4 length check and to do this for all
supported inner protocols in the same way.  Making the code common
between protocols also allows the existing ICMP related UDP tests to
cover TCP and ICMP cases.

Fixes: a489b16854b5 ("conntrack: New userspace connection tracker.")
CC: Daniele Di Proietto <diproiettod@vmware.com>
Reported-at: https://mail.openvswitch.org/pipermail/ovs-dev/2019-August/361949.html
Reported-by: Vishal Deep Ajmera <vishal.deep.ajmera@ericsson.com>
Signed-off-by: Vishal Deep Ajmera <vishal.deep.ajmera@ericsson.com>
Co-authored-by: Vishal Deep Ajmera <vishal.deep.ajmera@ericsson.com>
Signed-off-by: Darrell Ball <dlu998@gmail.com>
---
 lib/conntrack.c | 38 ++++++++++++++++++++++----------------
 lib/packets.h   |  3 +++
 2 files changed, 25 insertions(+), 16 deletions(-)

Comments

Darrell Ball Aug. 26, 2019, 4:17 p.m. UTC | #1
Resent this patch, as it had a bad e-mail address

Darrell

On Mon, Aug 26, 2019 at 9:06 AM Darrell Ball <dlu998@gmail.com> wrote:

> The ICMP error data L4 length check was found to be too strict for TCP,
> expecting a minimum of 20 rather than 8 bytes.  This worked by
> hapenstance for other inner protocols.  The approach is to explicitly
> handle the ICMPV4 error data L4 length check and to do this for all
> supported inner protocols in the same way.  Making the code common
> between protocols also allows the existing ICMP related UDP tests to
> cover TCP and ICMP cases.
>
> Fixes: a489b16854b5 ("conntrack: New userspace connection tracker.")
> CC: Daniele Di Proietto <diproiettod@vmware.com>
> Reported-at:
> https://mail.openvswitch.org/pipermail/ovs-dev/2019-August/361949.html
> Reported-by: Vishal Deep Ajmera <vishal.deep.ajmera@ericsson.com>
> Signed-off-by: Vishal Deep Ajmera <vishal.deep.ajmera@ericsson.com>
> Co-authored-by: Vishal Deep Ajmera <vishal.deep.ajmera@ericsson.com>
> Signed-off-by: Darrell Ball <dlu998@gmail.com>
> ---
>  lib/conntrack.c | 38 ++++++++++++++++++++++----------------
>  lib/packets.h   |  3 +++
>  2 files changed, 25 insertions(+), 16 deletions(-)
>
> diff --git a/lib/conntrack.c b/lib/conntrack.c
> index ecf3bcc..de0ab9b 100644
> --- a/lib/conntrack.c
> +++ b/lib/conntrack.c
> @@ -1565,9 +1565,10 @@ check_l4_icmp6(const struct conn_key *key, const
> void *data, size_t size,
>  }
>
>  static inline bool
> -extract_l4_tcp(struct conn_key *key, const void *data, size_t size)
> +extract_l4_tcp(struct conn_key *key, const void *data, size_t size,
> +               size_t *chk_len)
>  {
> -    if (OVS_UNLIKELY(size < TCP_HEADER_LEN)) {
> +    if (OVS_UNLIKELY(size < (chk_len ? *chk_len : TCP_HEADER_LEN))) {
>          return false;
>      }
>
> @@ -1580,9 +1581,10 @@ extract_l4_tcp(struct conn_key *key, const void
> *data, size_t size)
>  }
>
>  static inline bool
> -extract_l4_udp(struct conn_key *key, const void *data, size_t size)
> +extract_l4_udp(struct conn_key *key, const void *data, size_t size,
> +               size_t *chk_len)
>  {
> -    if (OVS_UNLIKELY(size < UDP_HEADER_LEN)) {
> +    if (OVS_UNLIKELY(size < (chk_len ? *chk_len : UDP_HEADER_LEN))) {
>          return false;
>      }
>
> @@ -1596,7 +1598,7 @@ extract_l4_udp(struct conn_key *key, const void
> *data, size_t size)
>
>  static inline bool extract_l4(struct conn_key *key, const void *data,
>                                size_t size, bool *related, const void *l3,
> -                              bool validate_checksum);
> +                              bool validate_checksum, size_t *chk_len);
>
>  static uint8_t
>  reverse_icmp_type(uint8_t type)
> @@ -1628,9 +1630,9 @@ reverse_icmp_type(uint8_t type)
>   * possible */
>  static inline int
>  extract_l4_icmp(struct conn_key *key, const void *data, size_t size,
> -                bool *related)
> +                bool *related, size_t *chk_len)
>  {
> -    if (OVS_UNLIKELY(size < ICMP_HEADER_LEN)) {
> +    if (OVS_UNLIKELY(size < (chk_len ? *chk_len : ICMP_HEADER_LEN))) {
>          return false;
>      }
>
> @@ -1681,8 +1683,9 @@ extract_l4_icmp(struct conn_key *key, const void
> *data, size_t size,
>          key->src = inner_key.src;
>          key->dst = inner_key.dst;
>          key->nw_proto = inner_key.nw_proto;
> +        size_t check_len = ICMP_ERROR_DATA_L4_LEN;
>
> -        ok = extract_l4(key, l4, tail - l4, NULL, l3, false);
> +        ok = extract_l4(key, l4, tail - l4, NULL, l3, false, &check_len);
>          if (ok) {
>              conn_key_reverse(key);
>              *related = true;
> @@ -1769,7 +1772,7 @@ extract_l4_icmp6(struct conn_key *key, const void
> *data, size_t size,
>          key->dst = inner_key.dst;
>          key->nw_proto = inner_key.nw_proto;
>
> -        ok = extract_l4(key, l4, tail - l4, NULL, l3, false);
> +        ok = extract_l4(key, l4, tail - l4, NULL, l3, false, NULL);
>          if (ok) {
>              conn_key_reverse(key);
>              *related = true;
> @@ -1797,23 +1800,25 @@ extract_l4_icmp6(struct conn_key *key, const void
> *data, size_t size,
>   * in an ICMP error.  In this case, we skip checksum and length
> validation. */
>  static inline bool
>  extract_l4(struct conn_key *key, const void *data, size_t size, bool
> *related,
> -           const void *l3, bool validate_checksum)
> +           const void *l3, bool validate_checksum, size_t *chk_len)
>  {
>      if (key->nw_proto == IPPROTO_TCP) {
>          return (!related || check_l4_tcp(key, data, size, l3,
> -                validate_checksum)) && extract_l4_tcp(key, data, size);
> +                validate_checksum))
> +               && extract_l4_tcp(key, data, size, chk_len);
>      } else if (key->nw_proto == IPPROTO_UDP) {
>          return (!related || check_l4_udp(key, data, size, l3,
> -                validate_checksum)) && extract_l4_udp(key, data, size);
> +                validate_checksum))
> +               && extract_l4_udp(key, data, size, chk_len);
>      } else if (key->dl_type == htons(ETH_TYPE_IP)
>                 && key->nw_proto == IPPROTO_ICMP) {
>          return (!related || check_l4_icmp(data, size, validate_checksum))
> -               && extract_l4_icmp(key, data, size, related);
> +               && extract_l4_icmp(key, data, size, related, chk_len);
>      } else if (key->dl_type == htons(ETH_TYPE_IPV6)
>                 && key->nw_proto == IPPROTO_ICMPV6) {
>          return (!related || check_l4_icmp6(key, data, size, l3,
> -                validate_checksum)) && extract_l4_icmp6(key, data, size,
> -                related);
> +                validate_checksum))
> +               && extract_l4_icmp6(key, data, size, related);
>      } else {
>          return false;
>      }
> @@ -1892,7 +1897,8 @@ conn_key_extract(struct conntrack *ct, struct
> dp_packet *pkt, ovs_be16 dl_type,
>              bool  hwol_good_l4_csum = dp_packet_l4_checksum_valid(pkt);
>              /* Validate the checksum only when hwol is not supported. */
>              if (extract_l4(&ctx->key, l4, dp_packet_l4_size(pkt),
> -                           &ctx->icmp_related, l3, !hwol_good_l4_csum)) {
> +                           &ctx->icmp_related, l3, !hwol_good_l4_csum,
> +                           NULL)) {
>                  ctx->hash = conn_key_hash(&ctx->key, ct->hash_basis);
>                  return true;
>              }
> diff --git a/lib/packets.h b/lib/packets.h
> index 0b3e3a2..c78defb 100644
> --- a/lib/packets.h
> +++ b/lib/packets.h
> @@ -780,6 +780,9 @@ struct icmp_header {
>  };
>  BUILD_ASSERT_DECL(ICMP_HEADER_LEN == sizeof(struct icmp_header));
>
> +/* ICMPV4 */
> +#define ICMP_ERROR_DATA_L4_LEN 8
> +
>  #define IGMP_HEADER_LEN 8
>  struct igmp_header {
>      uint8_t igmp_type;
> --
> 1.9.1
>
>

Patch
diff mbox series

diff --git a/lib/conntrack.c b/lib/conntrack.c
index ecf3bcc..de0ab9b 100644
--- a/lib/conntrack.c
+++ b/lib/conntrack.c
@@ -1565,9 +1565,10 @@  check_l4_icmp6(const struct conn_key *key, const void *data, size_t size,
 }
 
 static inline bool
-extract_l4_tcp(struct conn_key *key, const void *data, size_t size)
+extract_l4_tcp(struct conn_key *key, const void *data, size_t size,
+               size_t *chk_len)
 {
-    if (OVS_UNLIKELY(size < TCP_HEADER_LEN)) {
+    if (OVS_UNLIKELY(size < (chk_len ? *chk_len : TCP_HEADER_LEN))) {
         return false;
     }
 
@@ -1580,9 +1581,10 @@  extract_l4_tcp(struct conn_key *key, const void *data, size_t size)
 }
 
 static inline bool
-extract_l4_udp(struct conn_key *key, const void *data, size_t size)
+extract_l4_udp(struct conn_key *key, const void *data, size_t size,
+               size_t *chk_len)
 {
-    if (OVS_UNLIKELY(size < UDP_HEADER_LEN)) {
+    if (OVS_UNLIKELY(size < (chk_len ? *chk_len : UDP_HEADER_LEN))) {
         return false;
     }
 
@@ -1596,7 +1598,7 @@  extract_l4_udp(struct conn_key *key, const void *data, size_t size)
 
 static inline bool extract_l4(struct conn_key *key, const void *data,
                               size_t size, bool *related, const void *l3,
-                              bool validate_checksum);
+                              bool validate_checksum, size_t *chk_len);
 
 static uint8_t
 reverse_icmp_type(uint8_t type)
@@ -1628,9 +1630,9 @@  reverse_icmp_type(uint8_t type)
  * possible */
 static inline int
 extract_l4_icmp(struct conn_key *key, const void *data, size_t size,
-                bool *related)
+                bool *related, size_t *chk_len)
 {
-    if (OVS_UNLIKELY(size < ICMP_HEADER_LEN)) {
+    if (OVS_UNLIKELY(size < (chk_len ? *chk_len : ICMP_HEADER_LEN))) {
         return false;
     }
 
@@ -1681,8 +1683,9 @@  extract_l4_icmp(struct conn_key *key, const void *data, size_t size,
         key->src = inner_key.src;
         key->dst = inner_key.dst;
         key->nw_proto = inner_key.nw_proto;
+        size_t check_len = ICMP_ERROR_DATA_L4_LEN;
 
-        ok = extract_l4(key, l4, tail - l4, NULL, l3, false);
+        ok = extract_l4(key, l4, tail - l4, NULL, l3, false, &check_len);
         if (ok) {
             conn_key_reverse(key);
             *related = true;
@@ -1769,7 +1772,7 @@  extract_l4_icmp6(struct conn_key *key, const void *data, size_t size,
         key->dst = inner_key.dst;
         key->nw_proto = inner_key.nw_proto;
 
-        ok = extract_l4(key, l4, tail - l4, NULL, l3, false);
+        ok = extract_l4(key, l4, tail - l4, NULL, l3, false, NULL);
         if (ok) {
             conn_key_reverse(key);
             *related = true;
@@ -1797,23 +1800,25 @@  extract_l4_icmp6(struct conn_key *key, const void *data, size_t size,
  * in an ICMP error.  In this case, we skip checksum and length validation. */
 static inline bool
 extract_l4(struct conn_key *key, const void *data, size_t size, bool *related,
-           const void *l3, bool validate_checksum)
+           const void *l3, bool validate_checksum, size_t *chk_len)
 {
     if (key->nw_proto == IPPROTO_TCP) {
         return (!related || check_l4_tcp(key, data, size, l3,
-                validate_checksum)) && extract_l4_tcp(key, data, size);
+                validate_checksum))
+               && extract_l4_tcp(key, data, size, chk_len);
     } else if (key->nw_proto == IPPROTO_UDP) {
         return (!related || check_l4_udp(key, data, size, l3,
-                validate_checksum)) && extract_l4_udp(key, data, size);
+                validate_checksum))
+               && extract_l4_udp(key, data, size, chk_len);
     } else if (key->dl_type == htons(ETH_TYPE_IP)
                && key->nw_proto == IPPROTO_ICMP) {
         return (!related || check_l4_icmp(data, size, validate_checksum))
-               && extract_l4_icmp(key, data, size, related);
+               && extract_l4_icmp(key, data, size, related, chk_len);
     } else if (key->dl_type == htons(ETH_TYPE_IPV6)
                && key->nw_proto == IPPROTO_ICMPV6) {
         return (!related || check_l4_icmp6(key, data, size, l3,
-                validate_checksum)) && extract_l4_icmp6(key, data, size,
-                related);
+                validate_checksum))
+               && extract_l4_icmp6(key, data, size, related);
     } else {
         return false;
     }
@@ -1892,7 +1897,8 @@  conn_key_extract(struct conntrack *ct, struct dp_packet *pkt, ovs_be16 dl_type,
             bool  hwol_good_l4_csum = dp_packet_l4_checksum_valid(pkt);
             /* Validate the checksum only when hwol is not supported. */
             if (extract_l4(&ctx->key, l4, dp_packet_l4_size(pkt),
-                           &ctx->icmp_related, l3, !hwol_good_l4_csum)) {
+                           &ctx->icmp_related, l3, !hwol_good_l4_csum,
+                           NULL)) {
                 ctx->hash = conn_key_hash(&ctx->key, ct->hash_basis);
                 return true;
             }
diff --git a/lib/packets.h b/lib/packets.h
index 0b3e3a2..c78defb 100644
--- a/lib/packets.h
+++ b/lib/packets.h
@@ -780,6 +780,9 @@  struct icmp_header {
 };
 BUILD_ASSERT_DECL(ICMP_HEADER_LEN == sizeof(struct icmp_header));
 
+/* ICMPV4 */
+#define ICMP_ERROR_DATA_L4_LEN 8
+
 #define IGMP_HEADER_LEN 8
 struct igmp_header {
     uint8_t igmp_type;