[ovs-dev,v2] datapath-windows: Fix potential memory leak while creating conntrack entry

OvsCtAddEntry returns TRUE or FALSE depending on whether
OvsNatTranslateCtEntry was successful or not. In the case of an
unsuccesful NAT translation, this will fail to insert the newly created
entry to the Conntrack Table. This entry needs to be freed and the states
should be accordingly in the flowKey instead of returning out.

Consolidated the parentEntry lookup and assignment portion across
different protocols and some minor refactoring to make the code more
readable.

Tests Done: Enabled driver verifier and tested the following:
- TCP & ICMP traffic through Conntrack Module.
- Flushed Conntrack Entries while traffic was flowing.
- Uninstalled and re-installed the driver when traffic was in progress.

Signed-off-by: Sairam Venugopal <vsairam@vmware.com>
---
 datapath-windows/ovsext/Conntrack.c | 123 +++++++++++++++++-------------------
 1 file changed, 57 insertions(+), 66 deletions(-)

On 21 June 2017 at 10:08, Sairam Venugopal <vsairam@vmware.com> wrote:

> OvsCtAddEntry returns TRUE or FALSE depending on whether
> OvsNatTranslateCtEntry was successful or not. In the case of an
> unsuccesful NAT translation, this will fail to insert the newly created
> entry to the Conntrack Table. This entry needs to be freed and the states
> should be accordingly in the flowKey instead of returning out.
>
> Consolidated the parentEntry lookup and assignment portion across
> different protocols and some minor refactoring to make the code more
> readable.
>
> Tests Done: Enabled driver verifier and tested the following:
> - TCP & ICMP traffic through Conntrack Module.
> - Flushed Conntrack Entries while traffic was flowing.
> - Uninstalled and re-installed the driver when traffic was in progress.
>
> Signed-off-by: Sairam Venugopal <vsairam@vmware.com>
>
Applied, thanks!


> ---
>  datapath-windows/ovsext/Conntrack.c | 123 +++++++++++++++++-------------
> ------
>  1 file changed, 57 insertions(+), 66 deletions(-)
>
> diff --git a/datapath-windows/ovsext/Conntrack.c
> b/datapath-windows/ovsext/Conntrack.c
> index 68ed395..b010484 100644
> --- a/datapath-windows/ovsext/Conntrack.c
> +++ b/datapath-windows/ovsext/Conntrack.c
> @@ -214,87 +214,78 @@ OvsCtEntryCreate(OvsForwardingContext *fwdCtx,
>                   BOOLEAN *entryCreated)
>  {
>      POVS_CT_ENTRY entry = NULL;
> -    *entryCreated = FALSE;
>      UINT32 state = 0;
> +    POVS_CT_ENTRY parentEntry;
>      PNET_BUFFER_LIST curNbl = fwdCtx->curNbl;
> -    switch (ipProto)
> -    {
> -        case IPPROTO_TCP:
> -        {
> -            TCPHdr tcpStorage;
> -            const TCPHdr *tcp;
> -            tcp = OvsGetTcp(curNbl, l4Offset, &tcpStorage);
> -            if (!OvsConntrackValidateTcpPacket(tcp)) {
> -                goto invalid;
> -            }
> -
> -            state |= OVS_CS_F_NEW;
> -            POVS_CT_ENTRY parentEntry;
> -            parentEntry = OvsCtRelatedLookup(ctx->key, currentTime);
> -            if (parentEntry != NULL) {
> -                state |= OVS_CS_F_RELATED;
> -            }
>
> -            if (commit) {
> -                entry = OvsConntrackCreateTcpEntry(tcp, curNbl,
> currentTime);
> -                if (!entry) {
> -                    return NULL;
> -                }
> +    *entryCreated = FALSE;
> +    state |= OVS_CS_F_NEW;
>
> -                /* Set parent entry for related FTP connections */
> -                entry->parent = parentEntry;
> +    parentEntry = OvsCtRelatedLookup(ctx->key, currentTime);
> +    if (parentEntry != NULL) {
> +        state |= OVS_CS_F_RELATED;
> +    }
>
> -                *entryCreated = TRUE;
> -            }
> +    switch (ipProto) {
> +    case IPPROTO_TCP:
> +    {
> +        TCPHdr tcpStorage;
> +        const TCPHdr *tcp;
> +        tcp = OvsGetTcp(curNbl, l4Offset, &tcpStorage);
> +        if (!OvsConntrackValidateTcpPacket(tcp)) {
> +            state = OVS_CS_F_INVALID;
>              break;
>          }
> -        case IPPROTO_ICMP:
> -        {
> -            ICMPHdr storage;
> -            const ICMPHdr *icmp;
> -            icmp = OvsGetIcmp(curNbl, l4Offset, &storage);
> -            if (!OvsConntrackValidateIcmpPacket(icmp)) {
> -                goto invalid;
> -            }
>
> -            state |= OVS_CS_F_NEW;
> -            if (commit) {
> -                entry = OvsConntrackCreateIcmpEntry(currentTime);
> -                if (entry) {
> -                    /* XXX Add support for ICMP-Related */
> -                    entry->parent = NULL;
> -                }
> -                *entryCreated = TRUE;
> -            }
> +        if (commit) {
> +            entry = OvsConntrackCreateTcpEntry(tcp, curNbl, currentTime);
> +        }
> +        break;
> +    }
> +    case IPPROTO_ICMP:
> +    {
> +        ICMPHdr storage;
> +        const ICMPHdr *icmp;
> +        icmp = OvsGetIcmp(curNbl, l4Offset, &storage);
> +        if (!OvsConntrackValidateIcmpPacket(icmp)) {
> +            state = OVS_CS_F_INVALID;
>              break;
>          }
> -        case IPPROTO_UDP:
> -        {
> -            state |= OVS_CS_F_NEW;
> -            if (commit) {
> -                entry = OvsConntrackCreateOtherEntry(currentTime);
> -                if (entry) {
> -                    /* Default UDP related to NULL until TFTP is
> supported */
> -                    entry->parent = NULL;
> -                }
> +
> +        if (commit) {
> +            entry = OvsConntrackCreateIcmpEntry(currentTime);
> +        }
> +        break;
> +    }
> +    case IPPROTO_UDP:
> +    {
> +        if (commit) {
> +            entry = OvsConntrackCreateOtherEntry(currentTime);
> +        }
> +        break;
> +    }
> +    default:
> +        state = OVS_CS_F_INVALID;
> +        break;
> +    }
> +
> +    if (state != OVS_CS_F_INVALID && commit) {
> +        if (entry) {
> +            entry->parent = parentEntry;
> +            if (OvsCtAddEntry(entry, ctx, natInfo, currentTime)) {
>                  *entryCreated = TRUE;
> +            } else {
> +                /* Unable to add entry to the list */
> +                OvsFreeMemoryWithTag(entry, OVS_CT_POOL_TAG);
> +                state = OVS_CS_F_INVALID;
> +                entry = NULL;
>              }
> -            break;
> +        } else {
> +            /* OvsAllocateMemoryWithTag returned NULL; treat as invalid */
> +            state = OVS_CS_F_INVALID;
>          }
> -        default:
> -            goto invalid;
>      }
>
> -    if (commit && !entry) {
> -        return NULL;
> -    }
> -    if (entry && !OvsCtAddEntry(entry, ctx, natInfo, currentTime)) {
> -        return NULL;
> -    }
> -    OvsCtUpdateFlowKey(key, state, ctx->key.zone, 0, NULL);
> -    return entry;
> -invalid:
> -    state |= OVS_CS_F_INVALID;
>      OvsCtUpdateFlowKey(key, state, ctx->key.zone, 0, NULL);
>      return entry;
>  }
> --
> 2.9.0.windows.1
>
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