[llvm] [llvm-objdump][ELF]Fix crash when reading strings from .dynstr(#86612) (PR #125679)

[James Henderson via llvm-commits]

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@@ -235,6 +252,12 @@ template <class ELFT> void ELFDumper<ELFT>::printDynamicSection() {
       Expected<StringRef> StrTabOrErr = getDynamicStrTab(Elf);
       if (StrTabOrErr) {
         const char *Data = StrTabOrErr->data();
+        if (Dyn.getVal() >= StringTableSize) {
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jh7370 wrote:

This will only catch the class of cases where the tag points at or past the end of the string table. Are there existing checks anywhere that ensures the string table ends with a null byte (there might be - I haven't checked all the code)? Otherwise, you could have a case where the tag points within the table, but reading the data still reads garbage. Again, if you want to validate this, you could do so with a separate warning in a separate PR.

https://github.com/llvm/llvm-project/pull/125679