Re: [PATCH] s390: Warn if kernel command line contains non-printable EBCDIC characters
Ilya Leoshkevich <[email protected]>
| Newsgroups | org.kernel.vger.linux-s390,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On 8/26/26 15:51, David Laight wrote: > On Tue, 25 Aug 2026 17:08:08 +0200 > Ilya Leoshkevich <[email protected]> wrote: > >> Users may accidentally add multi-byte UTF-8 characters to zipl.conf >> parmline, for example, by copying snippets containing non-breaking >> spaces (\xC2\xA0) from web pages. >> >> The kernel will then interpret the entire command line as EBCDIC, >> making it unusable. Distinguish this situation from the legitimate >> EBCDIC conversion by looking for non-printable characters and issue >> a warning. > > Would it be better to check for the entire line being printable ebcdic? > All of EBCDIC a-zA-Z0-9 have the 0x80 bit set and most of 0x20..0x7f > are invalid or control characters (or punctuation). > > David I actually started with that, but this required introducing a new _ctype-like table (unfortunately it's not as simple as checking a couple ranges), so I decided against that and took a shortcut via ASCII. [...]