Messages in this thread | | | Date | Tue, 9 Oct 2018 17:23:11 -0400 | From | Steven Rostedt <> | Subject | Re: [RFC PATCH] kernel/panic: Filter out a potential trailing newline |
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On Tue, 9 Oct 2018 22:50:19 +0200 Borislav Petkov <bp@alien8.de> wrote:
> From: Borislav Petkov <bp@suse.de> > > If a call to panic() terminates the string with a \n, the result puts > the closing brace ']---' on a newline because panic() itself adds \n > too. > > Now, if one goes and removes the newline chars from all panic() > invocations - and the stats right now look like this: > > ~300 calls with an \n > ~500 calls without a \n > > one is destined to a neverending game of whack-a-mole because the usual > thing to do is add a newline at the end of a string a function is > supposed to print. > > Therefore, simply zap any \n at the end of the panic string to avoid > touching so many places in the kernel. > > Signed-off-by: Borislav Petkov <bp@suse.de> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Kees Cook <keescook@chromium.org> > Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org> > Cc: x86@kernel.org > --- > kernel/panic.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/kernel/panic.c b/kernel/panic.c > index 8b2e002d52eb..5776d2879650 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -136,7 +136,7 @@ void panic(const char *fmt, ...) > { > static char buf[1024]; > va_list args; > - long i, i_next = 0; > + long i, i_next = 0, len; > int state = 0; > int old_cpu, this_cpu; > bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; > @@ -173,8 +173,12 @@ void panic(const char *fmt, ...) > console_verbose(); > bust_spinlocks(1); > va_start(args, fmt); > - vsnprintf(buf, sizeof(buf), fmt, args); > + len = vscnprintf(buf, sizeof(buf), fmt, args); > va_end(args); > + > + if (len && buf[len - 1] == '\n') > + buf[len - 1] = '\0'; > + > pr_emerg("Kernel panic - not syncing: %s\n", buf); > #ifdef CONFIG_DEBUG_BUGVERBOSE > /*
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
-- Steve
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