[ovs-dev] [PATCH] ofproto-dpif: Fix using uninitialised memory in user_action_cookie.

Ilya Maximets i.maximets at samsung.com
Thu Aug 22 07:39:25 UTC 2019


On 25.07.2019 19:31, Ilya Maximets wrote:
> Designated initializers are not suitable for initializing non-packed
> structures and unions which are subjects for comparison by memcmp().
> 
> Whole memory for 'struct user_action_cookie' must be explicitly cleared
> before using because it will be copied with memcpy and later compared
> by memcmp in ofpbuf_equal().
> 
> Few issues found be valgrind:
> 
>  Thread 13 revalidator11:
>  Conditional jump or move depends on uninitialised value(s)
>     at 0x4C35D96: __memcmp_sse4_1 (in vgpreload_memcheck.so)
>     by 0x9D4404: ofpbuf_equal (ofpbuf.h:273)
>     by 0x9D4404: revalidate_ukey__ (ofproto-dpif-upcall.c:2219)
>     by 0x9D4404: revalidate_ukey (ofproto-dpif-upcall.c:2286)
>     by 0x9D62AC: revalidate (ofproto-dpif-upcall.c:2685)
>     by 0x9D62AC: udpif_revalidator (ofproto-dpif-upcall.c:942)
>     by 0xA9C732: ovsthread_wrapper (ovs-thread.c:383)
>     by 0x5FF86DA: start_thread (pthread_create.c:463)
>     by 0x6AF488E: clone (clone.S:95)
>   Uninitialised value was created by a stack allocation
>     at 0x9D4450: compose_slow_path (ofproto-dpif-upcall.c:1062)
> 
>  Thread 11 revalidator16:
>  Conditional jump or move depends on uninitialised value(s)
>     at 0x4C35D96: __memcmp_sse4_1 (in vgpreload_memcheck.so)
>     by 0x9D4404: ofpbuf_equal (ofpbuf.h:273)
>     by 0x9D4404: revalidate_ukey__ (ofproto-dpif-upcall.c:2220)
>     by 0x9D4404: revalidate_ukey (ofproto-dpif-upcall.c:2287)
>     by 0x9D62BC: revalidate (ofproto-dpif-upcall.c:2686)
>     by 0x9D62BC: udpif_revalidator (ofproto-dpif-upcall.c:942)
>     by 0xA9C6D2: ovsthread_wrapper (ovs-thread.c:383)
>     by 0x5FF86DA: start_thread (pthread_create.c:463)
>     by 0x6AF488E: clone (clone.S:95)
>   Uninitialised value was created by a stack allocation
>     at 0x9DC4E0: compose_sflow_action (ofproto-dpif-xlate.c:3211)
> 
> The struct was never marked as 'packed', however it was manually
> adjusted to be so in practice.
> Old IPFIX related commit first made the structure non-contiguous.
> Commit 8de6ff3ea864 ("ofproto-dpif: Use a fixed size userspace cookie.")
> added uninitialized parts of the additional union space and the next
> one introduced new holes between structure fields for all cases.
> 
> CC: Justin Pettit <jpettit at ovn.org>
> Fixes: 8b7ea2d48033 ("Extend OVS IPFIX exporter to export tunnel headers")
> Fixes: 8de6ff3ea864 ("ofproto-dpif: Use a fixed size userspace cookie.")
> Fixes: fcb9579be3c7 ("ofproto: Add 'ofproto_uuid' and 'ofp_in_port' to user action cookie.")
> Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
> ---

Kind reminder.
It'll be good to have this before the official 2.12 release.

Best regards, Ilya Maximets.

>  ofproto/ofproto-dpif-upcall.c |  1 +
>  ofproto/ofproto-dpif-xlate.c  | 52 +++++++++++++++++++----------------
>  2 files changed, 29 insertions(+), 24 deletions(-)
> 
> diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c
> index 731ee7280..f46cdf213 100644
> --- a/ofproto/ofproto-dpif-upcall.c
> +++ b/ofproto/ofproto-dpif-upcall.c
> @@ -1064,6 +1064,7 @@ compose_slow_path(struct udpif *udpif, struct xlate_out *xout,
>      odp_port_t port;
>      uint32_t pid;
>  
> +    memset(&cookie, 0, sizeof cookie);
>      cookie.type = USER_ACTION_COOKIE_SLOW_PATH;
>      cookie.ofp_in_port = ofp_in_port;
>      cookie.ofproto_uuid = *ofproto_uuid;
> diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
> index 28a7fdd84..b7da8cead 100644
> --- a/ofproto/ofproto-dpif-xlate.c
> +++ b/ofproto/ofproto-dpif-xlate.c
> @@ -3214,11 +3214,13 @@ compose_sflow_action(struct xlate_ctx *ctx)
>          return 0;
>      }
>  
> -    struct user_action_cookie cookie = {
> -        .type = USER_ACTION_COOKIE_SFLOW,
> -        .ofp_in_port = ctx->xin->flow.in_port.ofp_port,
> -        .ofproto_uuid = ctx->xbridge->ofproto->uuid
> -    };
> +    struct user_action_cookie cookie;
> +
> +    memset(&cookie, 0, sizeof cookie);
> +    cookie.type = USER_ACTION_COOKIE_SFLOW;
> +    cookie.ofp_in_port = ctx->xin->flow.in_port.ofp_port;
> +    cookie.ofproto_uuid = ctx->xbridge->ofproto->uuid;
> +
>      return compose_sample_action(ctx, dpif_sflow_get_probability(sflow),
>                                   &cookie, ODPP_NONE, true);
>  }
> @@ -3258,12 +3260,14 @@ compose_ipfix_action(struct xlate_ctx *ctx, odp_port_t output_odp_port)
>          }
>      }
>  
> -    struct user_action_cookie cookie = {
> -        .type = USER_ACTION_COOKIE_IPFIX,
> -        .ofp_in_port = ctx->xin->flow.in_port.ofp_port,
> -        .ofproto_uuid = ctx->xbridge->ofproto->uuid,
> -        .ipfix.output_odp_port = output_odp_port
> -    };
> +    struct user_action_cookie cookie;
> +
> +    memset(&cookie, 0, sizeof cookie);
> +    cookie.type = USER_ACTION_COOKIE_IPFIX;
> +    cookie.ofp_in_port = ctx->xin->flow.in_port.ofp_port;
> +    cookie.ofproto_uuid = ctx->xbridge->ofproto->uuid;
> +    cookie.ipfix.output_odp_port = output_odp_port;
> +
>      compose_sample_action(ctx,
>                            dpif_ipfix_get_bridge_exporter_probability(ipfix),
>                            &cookie, tunnel_out_port, false);
> @@ -5521,19 +5525,19 @@ xlate_sample_action(struct xlate_ctx *ctx,
>          }
>      }
>  
> -    struct user_action_cookie cookie = {
> -        .type = USER_ACTION_COOKIE_FLOW_SAMPLE,
> -        .ofp_in_port = ctx->xin->flow.in_port.ofp_port,
> -        .ofproto_uuid = ctx->xbridge->ofproto->uuid,
> -        .flow_sample = {
> -            .probability = os->probability,
> -            .collector_set_id = os->collector_set_id,
> -            .obs_domain_id = os->obs_domain_id,
> -            .obs_point_id = os->obs_point_id,
> -            .output_odp_port = output_odp_port,
> -            .direction = os->direction,
> -        }
> -    };
> +    struct user_action_cookie cookie;
> +
> +    memset(&cookie, 0, sizeof cookie);
> +    cookie.type = USER_ACTION_COOKIE_FLOW_SAMPLE;
> +    cookie.ofp_in_port = ctx->xin->flow.in_port.ofp_port;
> +    cookie.ofproto_uuid = ctx->xbridge->ofproto->uuid;
> +    cookie.flow_sample.probability = os->probability;
> +    cookie.flow_sample.collector_set_id = os->collector_set_id;
> +    cookie.flow_sample.obs_domain_id = os->obs_domain_id;
> +    cookie.flow_sample.obs_point_id = os->obs_point_id;
> +    cookie.flow_sample.output_odp_port = output_odp_port;
> +    cookie.flow_sample.direction = os->direction;
> +
>      compose_sample_action(ctx, probability, &cookie, tunnel_out_port, false);
>  }
>  
> 


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