On Tue, Oct 9, 2018 at 1:50 PM, Borislav Petkov <[email protected]> wrote: > From: Borislav Petkov <[email protected]> > > 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 <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Kees Cook <[email protected]> > Cc: "Steven Rostedt (VMware)" <[email protected]> > Cc: [email protected]
Ah yes, I like this. :) Acked-by: Kees Cook <[email protected]> -Kees > --- > 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 > /* > -- > 2.19.0.271.gfe8321ec057f > -- Kees Cook Pixel Security
