kernel/kexec.c: use vscnprintf() instead of vsnprintf() in vmcoreinfo_append_str()

vsnprintf() may let 'r' larger than sizeof(buf), in this case, if 'r' is
also less than "vmcoreinfo_max_size - vmcoreinfo_size" (left size of
destination buffer), next memcpy() will read the unexpected addresses.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/kexec.c b/kernel/kexec.c
index ac738781d356..60bafbed06ab 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1537,7 +1537,7 @@ void vmcoreinfo_append_str(const char *fmt, ...)
         size_t r;
 
         va_start(args, fmt);
-        r = vsnprintf(buf, sizeof(buf), fmt, args);
+        r = vscnprintf(buf, sizeof(buf), fmt, args);
         va_end(args);
 
         r = min(r, vmcoreinfo_max_size - vmcoreinfo_size);