From 464d62421cb8b2a6812dcb8c45184ff17b1bc5da Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 4 Jun 2017 03:24:26 -0400
Subject: [PATCH] select: switch compat_{get,put}_fd_set() to
compat_{get,put}_bitmap()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/select.c | 44 +++++---------------------------------------
1 file changed, 5 insertions(+), 39 deletions(-)
diff --git a/fs/select.c b/fs/select.c
index d6c652a31e99d..806d2d92672f3 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -1161,59 +1161,25 @@ static
int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
unsigned long *fdset)
{
- nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS);
if (ufdset) {
- unsigned long odd;
-
- if (!access_ok(VERIFY_WRITE, ufdset, nr*sizeof(compat_ulong_t)))
- return -EFAULT;
-
- odd = nr & 1UL;
- nr &= ~1UL;
- while (nr) {
- unsigned long h, l;
- if (__get_user(l, ufdset) || __get_user(h, ufdset+1))
- return -EFAULT;
- ufdset += 2;
- *fdset++ = h << 32 | l;
- nr -= 2;
- }
- if (odd && __get_user(*fdset, ufdset))
- return -EFAULT;
+ return compat_get_bitmap(fdset, ufdset, nr);
} else {
/* Tricky, must clear full unsigned long in the
- * kernel fdset at the end, this makes sure that
+ * kernel fdset at the end, ALIGN makes sure that
* actually happens.
*/
- memset(fdset, 0, ((nr + 1) & ~1)*sizeof(compat_ulong_t));
+ memset(fdset, 0, ALIGN(nr, BITS_PER_LONG));
+ return 0;
}
- return 0;
}
static
int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
unsigned long *fdset)
{
- unsigned long odd;
- nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS);
-
if (!ufdset)
return 0;
-
- odd = nr & 1UL;
- nr &= ~1UL;
- while (nr) {
- unsigned long h, l;
- l = *fdset++;
- h = l >> 32;
- if (__put_user(l, ufdset) || __put_user(h, ufdset+1))
- return -EFAULT;
- ufdset += 2;
- nr -= 2;
- }
- if (odd && __put_user(*fdset, ufdset))
- return -EFAULT;
- return 0;
+ return compat_put_bitmap(ufdset, fdset, nr);
}
--
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