[PATCH] D50387: [WASM] Fix overflow when reading custom section

[Jonas Devlieghere via Phabricator via llvm-commits]

JDevlieghere added inline comments.


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Comment at: llvm/lib/Object/WasmObjectFile.cpp:222
+    const uint32_t NameLength = Ctx.Ptr - NameStart;
+    if (NameLength > Size)
+      return make_error<StringError>(
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sbc100 wrote:
> JDevlieghere wrote:
> > Can this section be empty? (i.e. should I make this greater or equal)
> I think the ReadContext is probably a better way to enforce this.  readString already does this check based on the context.
> 
> This check seems a little strange since it reads the string before checking if its too long.
> 
I started out by doing that that but then you still have to update the current pointer and the size which made the code less intuitive. That combined with a less readable error message made me go this route. I'm happy to change it if you still think the ReadContext is better given the context. (pun not intended :-) 


Repository:
  rL LLVM

https://reviews.llvm.org/D50387