From 281327c99bcaa8dbd4fe49cc32178dc59b0e61b8 Mon Sep 17 00:00:00 2001 From: Yury Norov Date: Tue, 14 May 2019 15:43:11 -0700 Subject: [PATCH] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist() Patch series "lib: rework bitmap_parselist and tests", v5. bitmap_parselist has been evolved from a pretty simple idea for long and now lacks for refactoring. It is not structured, has nested loops and a set of opaque-named variables. Things are more complicated because bitmap_parselist() is a part of user interface, and its behavior should not change. In this patchset - bitmap_parselist_user() made a wrapper on bitmap_parselist(); - bitmap_parselist() reworked (patch 2); - time measurement in test_bitmap_parselist switched to ktime_get (patch 3); - new tests introduced (patch 4), and - bitmap_parselist_user() testing enabled with the same testset as bitmap_parselist() (patch 5). This patch (of 5): Currently we parse user data byte after byte which leads to overcomplification of parsing algorithm. The only user of bitmap_parselist_user() is not performance-critical, and so we can duplicate user data to kernel buffer and simply call bitmap_parselist(). This rework lets us unify and simplify bitmap_parselist() and bitmap_parselist_user(), which is done in the following patch. Link: http://lkml.kernel.org/r/20190405173211.11373-2-ynorov@marvell.com Signed-off-by: Yury Norov Reviewed-by: Andy Shevchenko Cc: Rasmus Villemoes Cc: Arnd Bergmann Cc: Kees Cook Cc: Matthew Wilcox Cc: Tetsuo Handa Cc: Mike Travis Cc: Guenter Roeck Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/bitmap.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index 3f3b8051f342..c63ddd06a5da 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -632,19 +632,22 @@ EXPORT_SYMBOL(bitmap_parselist); * @nmaskbits: size of bitmap, in bits. * * Wrapper for bitmap_parselist(), providing it with user buffer. - * - * We cannot have this as an inline function in bitmap.h because it needs - * linux/uaccess.h to get the access_ok() declaration and this causes - * cyclic dependencies. */ int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen, unsigned long *maskp, int nmaskbits) { - if (!access_ok(ubuf, ulen)) - return -EFAULT; - return __bitmap_parselist((const char __force *)ubuf, - ulen, 1, maskp, nmaskbits); + char *buf; + int ret; + + buf = memdup_user_nul(ubuf, ulen); + if (IS_ERR(buf)) + return PTR_ERR(buf); + + ret = bitmap_parselist(buf, maskp, nmaskbits); + + kfree(buf); + return ret; } EXPORT_SYMBOL(bitmap_parselist_user); -- 2.30.2