Messages in this thread | | | Date | Wed, 22 Jun 2011 20:53:55 +0400 | From | Vasiliy Kulikov <> | Subject | Re: [PATCH] kernel: escape non-ASCII and control characters in printk() |
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On Wed, Jun 22, 2011 at 09:38 -0700, Joe Perches wrote: > On Wed, 2011-06-22 at 13:53 +0400, Vasiliy Kulikov wrote: > > This patch escapes all characters outside of allowed '\n' plus 0x20-0x7E > > charset passed to printk(). > > [] > > > diff --git a/kernel/printk.c b/kernel/printk.c > [] > > +static void emit_log_char_escaped(char c) > > +{ > > + char buffer[8]; > > + int i, len; > > + > > + if ((c >= ' ' && c < 127) || c == '\n') > > if (isprint(c))
#define isprint(c) ((__ismask(c)&(_P|_U|_L|_D|_SP)) != 0)
It slightly differs from what I've written. It (1) lacks '\n', (2) passes non-ASCII symbols. How would non-ASCII symbols look like if terminal doesn't support it? (I don't know, merely asking).
But if >159 (the number got from _ctype[]) is not an issue then (isprint(c) || (c == '\n')) looks really better.
> Why not add this to emit_log_char?
No real need, but someone may want to explicitly bypass the check, it should use emit_log_char() instead of emit_log_char_escaped().
Thanks,
-- Vasiliy Kulikov http://www.openwall.com - bringing security into open computing environments
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