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Fix CVE-2016-6265 (use after free in pdf_load_xref()).
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-6265
https://security-tracker.debian.org/tracker/CVE-2016-6265
Patch copied from upstream source repository:
http://git.ghostscript.com/?p=mupdf.git;h=fa1936405b6a84e5c9bb440912c23d532772f958
diff --git a/source/pdf/pdf-xref.c b/source/pdf/pdf-xref.c
index 576c315..3222599 100644
--- a/source/pdf/pdf-xref.c
+++ b/source/pdf/pdf-xref.c
@@ -1184,8 +1184,14 @@ pdf_load_xref(fz_context *ctx, pdf_document *doc, pdf_lexbuf *buf)
fz_throw(ctx, FZ_ERROR_GENERIC, "object offset out of range: %d (%d 0 R)", (int)entry->ofs, i);
}
if (entry->type == 'o')
- if (entry->ofs <= 0 || entry->ofs >= xref_len || pdf_get_xref_entry(ctx, doc, entry->ofs)->type != 'n')
- fz_throw(ctx, FZ_ERROR_GENERIC, "invalid reference to an objstm that does not exist: %d (%d 0 R)", (int)entry->ofs, i);
+ {
+ /* Read this into a local variable here, because pdf_get_xref_entry
+ * may solidify the xref, hence invalidating "entry", meaning we
+ * need a stashed value for the throw. */
+ fz_off_t ofs = entry->ofs;
+ if (ofs <= 0 || ofs >= xref_len || pdf_get_xref_entry(ctx, doc, ofs)->type != 'n')
+ fz_throw(ctx, FZ_ERROR_GENERIC, "invalid reference to an objstm that does not exist: %d (%d 0 R)", (int)ofs, i);
+ }
}
}
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