提交 8e2a2bfd 编写于 作者: R Rasmus Villemoes 提交者: Linus Torvalds

lib/kasprintf.c: add sanity check to kvasprintf

kasprintf relies on being able to replay the formatting and getting the
same result (in particular, the same length).  This will almost always
work, but it is possible that the object pointed to by a %s or %p
argument changed under us (so we might get truncated output).  Add a
somewhat paranoid sanity check and let's see if it ever triggers.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Maurizio Lombardi <mlombard@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 4d72ba01
......@@ -13,19 +13,21 @@
/* Simplified asprintf. */
char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap)
{
unsigned int len;
unsigned int first, second;
char *p;
va_list aq;
va_copy(aq, ap);
len = vsnprintf(NULL, 0, fmt, aq);
first = vsnprintf(NULL, 0, fmt, aq);
va_end(aq);
p = kmalloc_track_caller(len+1, gfp);
p = kmalloc_track_caller(first+1, gfp);
if (!p)
return NULL;
vsnprintf(p, len+1, fmt, ap);
second = vsnprintf(p, first+1, fmt, ap);
WARN(first != second, "different return values (%u and %u) from vsnprintf(\"%s\", ...)",
first, second, fmt);
return p;
}
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册