[llvm] [llvm-objdump][ELF] Ensure offset to verdaux entry array does not go past size (PR #115284)

[James Henderson via llvm-commits]

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@@ -398,6 +401,12 @@ static void printSymbolVersionDefinition(const typename ELFT::Shdr &Shdr,
            << format("0x%08" PRIx32 " ", (uint32_t)Verdef->vd_hash);
 
     const uint8_t *BufAux = Buf + Verdef->vd_aux;
+    if (BufAux > Contents.end()) {
+      reportWarning("corrupted section: vd_aux value " + Twine(Verdef->vd_aux) +
+                        " in section verdef points past end of the section",
+                    Obj.getFileName());
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jh7370 wrote:

> I went with 'vd_aux value %val in section verdef points past end of the section, corrupted section,' as I don't think it’s that relevant to provide the exact byte count by which the aux entry went out of bounds. I added 'corrupted section' consistently with the other warnings.

I just searched for the string "corrupted section" and haven't found any relevant reference. What other warnings are you trying to be consistent with?

Please use the `describe` method (in Object\ELF.h) in place of "in section verdef" to be consistent with other recent messages added/changed in llvm-readelf.

The idea of including the section size is that it could be the size that is malformed, not the vd_aux value (for whatever reason). ELFDumper.cpp in llvm-readelf has a number of examples of this sort of message pattern (search for "past the end"). There may be others too.

https://github.com/llvm/llvm-project/pull/115284