The patch titled
Subject: kernel/panic.c: filter out a potential trailing newline
has been added to the -mm tree. Its filename is
kernel-panic-filter-out-a-potential-trailing-newline.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kernel-panic-filter-out-a-potential-trailing-newline.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kernel-panic-filter-out-a-potential-trailing-newline.patch
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------------------------------------------------------
From: Borislav Petkov <bp@xxxxxxx>
Subject: kernel/panic.c: filter out a potential trailing newline
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 a \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.
Link: http://lkml.kernel.org/r/20181009205019.2786-1-bp@xxxxxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN kernel/panic.c~kernel-panic-filter-out-a-potential-trailing-newline kernel/panic.c
--- a/kernel/panic.c~kernel-panic-filter-out-a-potential-trailing-newline
+++ a/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
/*
_
Patches currently in -mm which might be from bp@xxxxxxx are
kernel-panic-filter-out-a-potential-trailing-newline.patch
