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<base href="https://bugzilla.netfilter.org/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - EMLINK error for NFT_GOTO"
href="https://bugzilla.netfilter.org/show_bug.cgi?id=1459">1459</a>
</td>
</tr>
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<th>Summary</th>
<td>EMLINK error for NFT_GOTO
</td>
</tr>
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<th>Product</th>
<td>nftables
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
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<th>Hardware</th>
<td>x86_64
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P5
</td>
</tr>
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<th>Component</th>
<td>kernel
</td>
</tr>
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<th>Assignee</th>
<td>pablo@netfilter.org
</td>
</tr>
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<th>Reporter</th>
<td>steve@opendium.com
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=605" name="attach_605" title="Don't increment pctx->level when following gotos">attachment 605</a> <a href="attachment.cgi?id=605&action=edit" title="Don't increment pctx->level when following gotos">[details]</a></span>
Don't increment pctx->level when following gotos
nft_immediate_validate() and nft_lookup_validate_setelem() treat NFT_GOTO and
NFT_JUMP identically, incrementing pctx->level for both. This results in a
-EMLINK ("Too many links") being unexpectedly returned for rulesets that use
lots of gotos.
Having looked at other parts of the code, I can't see a reason for incrementing
the stack level for NFT_GOTO - it doesn't appear to use any real stack space.
The attached patch fixes this problem.
A couple of stylistic comments on the code, which I haven't attempted to fix:
1. ctx is passed as a const, but the constness is cast away, which isn't great
practice.
2. ctx->level is modified, even though ctx is passed as a const, and in the
case of an error the original value isn't restored. I'm guessing that the
caller probably throws away ctx anyway, so this probably doesn't have any
real-world implications, other than the potential for future bugs introduced by
someone expecting const to mean const.</pre>
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