Do not crash on small files that start with the PE magic

mlschroe · mlschroe · commit df7e8b3779c3 · 2026-02-11T10:09:25.000+01:00
diff --git a/generate_sbom b/generate_sbom
@@ -205,7 +205,7 @@ sub detect_mime {
     if ($first == 0xfeedface || $first == 0xfeedfacf || $first == 0xcefaedfe || $first == 0xcffaedfe) {
       return 'application/x-mach-binary';
     }
-    if (($first & 0xffff0000) == 0x4d5a0000) {
+    if (($first & 0xffff0000) == 0x4d5a0000 && length($prefix) >= 64) {
       my $o = unpack('@60V', $prefix);
       my $type = '';
       if (seek($fd, $o, 0) && read($fd, $type, 4) == 4 && unpack('N', $type) == 0x50450000) {

Original file line number	Diff line number	Diff line change
`@@ -205,7 +205,7 @@ sub detect_mime {`
`205`	`205`	`if ($first == 0xfeedface \|\| $first == 0xfeedfacf \|\| $first == 0xcefaedfe \|\| $first == 0xcffaedfe) {`
`206`	`206`	`return 'application/x-mach-binary';`
`207`	`207`	`}`
`208`		`- if (($first & 0xffff0000) == 0x4d5a0000) {`
	`208`	`+ if (($first & 0xffff0000) == 0x4d5a0000 && length($prefix) >= 64) {`
`209`	`209`	`my $o = unpack('@60V', $prefix);`
`210`	`210`	`my $type = '';`
`211`	`211`	`if (seek($fd, $o, 0) && read($fd, $type, 4) == 4 && unpack('N', $type) == 0x50450000) {`