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| author | Christoph Hellwig <hch@lst.de> | 2020-05-11 14:59:13 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-05-12 02:59:16 +0300 |
| commit | 1f466e1f15cf1dac7c86798d694649fc42cd868a (patch) | |
| tree | 1f8ca24224e9aa0dbaf924bec224deb08d1ab505 /net/ipv4/ip_sockglue.c | |
| parent | 2618d530dd8b7ac0fdcb83f4c95b88f7b0d37ce6 (diff) | |
| download | linux-1f466e1f15cf1dac7c86798d694649fc42cd868a.tar.xz | |
net: cleanly handle kernel vs user buffers for ->msg_control
The msg_control field in struct msghdr can either contain a user
pointer when used with the recvmsg system call, or a kernel pointer
when used with sendmsg. To complicate things further kernel_recvmsg
can stuff a kernel pointer in and then use set_fs to make the uaccess
helpers accept it.
Replace it with a union of a kernel pointer msg_control field, and
a user pointer msg_control_user one, and allow kernel_recvmsg operate
on a proper kernel pointer using a bitfield to override the normal
choice of a user pointer for recvmsg.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_sockglue.c')
| -rw-r--r-- | net/ipv4/ip_sockglue.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index aa3fd61818c4..8206047d70b6 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -1492,7 +1492,8 @@ static int do_ip_getsockopt(struct sock *sk, int level, int optname, if (sk->sk_type != SOCK_STREAM) return -ENOPROTOOPT; - msg.msg_control = (__force void *) optval; + msg.msg_control_is_user = true; + msg.msg_control_user = optval; msg.msg_controllen = len; msg.msg_flags = flags; |