From: Al Viro <viro@zeniv•linux.org.uk>
To: netdev@vger•kernel.org
Cc: David Miller <davem@davemloft•net>
Subject: [PATCH net-next] switch cmsghdr_from_user_compat_to_kern() to copy_from_user()
Date: Sun, 31 May 2020 02:06:55 +0100 [thread overview]
Message-ID: <20200531010655.GX23230@ZenIV.linux.org.uk> (raw)
no point getting compat_cmsghdr field-by-field
Signed-off-by: Al Viro <viro@zeniv•linux.org.uk>
---
diff --git a/net/compat.c b/net/compat.c
index afd7b444e0bf..5e3041a2c37d 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -183,20 +183,21 @@ int cmsghdr_from_user_compat_to_kern(struct msghdr *kmsg, struct sock *sk,
memset(kcmsg, 0, kcmlen);
ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);
while (ucmsg != NULL) {
- if (__get_user(ucmlen, &ucmsg->cmsg_len))
+ struct compat_cmsghdr cmsg;
+ if (copy_from_user(&cmsg, ucmsg, sizeof(cmsg)))
goto Efault;
- if (!CMSG_COMPAT_OK(ucmlen, ucmsg, kmsg))
+ if (!CMSG_COMPAT_OK(cmsg.cmsg_len, ucmsg, kmsg))
goto Einval;
- tmp = ((ucmlen - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
+ tmp = ((cmsg.cmsg_len - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
if ((char *)kcmsg_base + kcmlen - (char *)kcmsg < CMSG_ALIGN(tmp))
goto Einval;
kcmsg->cmsg_len = tmp;
+ kcmsg->cmsg_level = cmsg.cmsg_level;
+ kcmsg->cmsg_type = cmsg.cmsg_type;
tmp = CMSG_ALIGN(tmp);
- if (__get_user(kcmsg->cmsg_level, &ucmsg->cmsg_level) ||
- __get_user(kcmsg->cmsg_type, &ucmsg->cmsg_type) ||
- copy_from_user(CMSG_DATA(kcmsg),
+ if (copy_from_user(CMSG_DATA(kcmsg),
CMSG_COMPAT_DATA(ucmsg),
- (ucmlen - sizeof(*ucmsg))))
+ (cmsg.cmsg_len - sizeof(*ucmsg))))
goto Efault;
/* Advance. */
next reply other threads:[~2020-05-31 1:06 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-31 1:06 Al Viro [this message]
2020-06-01 19:06 ` [PATCH net-next] switch cmsghdr_from_user_compat_to_kern() to copy_from_user() David Miller
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