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Merge branch 'msg_control-split'

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Kevin Brodsky says:

====================
net: Finish up ->msg_control{,_user} split

Commit 1f466e1f15cf ("net: cleanly handle kernel vs user buffers for
->msg_control") introduced the msg_control_user and
msg_control_is_user fields in struct msghdr, to ensure that user
pointers are represented as such. It also took care of converting most
users of struct msghdr::msg_control where user pointers are involved. It
did however miss a number of cases, and some code using msg_control
inappropriately has also appeared in the meantime.

This series is attempting to complete the split, by eliminating the
remaining cases where msg_control is used when in fact a user
pointer is stored in the union (patch 1).

It also addresses a couple of issues with msg_control_is_user: one where
it is not updated as it should (patch 2), and one where it is not
initialised (patch 3).

v1..v2:
* Split out the msg_control_is_user fixes into separate patches.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2023-04-14 11:09:27 +01:00
commit c11d2e718c
4 changed files with 16 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
net/compat.c
View File

@ -113,7 +113,7 @@ int get_compat_msghdr(struct msghdr *kmsg,
#define CMSG_COMPAT_FIRSTHDR(msg) \
(((msg)->msg_controllen) >= sizeof(struct compat_cmsghdr) ? \
(struct compat_cmsghdr __user *)((msg)->msg_control) : \
(struct compat_cmsghdr __user *)((msg)->msg_control_user) : \
(struct compat_cmsghdr __user *)NULL)
#define CMSG_COMPAT_OK(ucmlen, ucmsg, mhdr) \
@ -126,7 +126,7 @@ static inline struct compat_cmsghdr __user *cmsg_compat_nxthdr(struct msghdr *ms
struct compat_cmsghdr __user *cmsg, int cmsg_len)
{
char __user *ptr = (char __user *)cmsg + CMSG_COMPAT_ALIGN(cmsg_len);
if ((unsigned long)(ptr + 1 - (char __user *)msg->msg_control) >
if ((unsigned long)(ptr + 1 - (char __user *)msg->msg_control_user) >
msg->msg_controllen)
return NULL;
return (struct compat_cmsghdr __user *)ptr;
@ -211,6 +211,7 @@ int cmsghdr_from_user_compat_to_kern(struct msghdr *kmsg, struct sock *sk,
goto Einval;
/* Ok, looks like we made it. Hook it up and return success. */
kmsg->msg_control_is_user = false;
kmsg->msg_control = kcmsg_base;
kmsg->msg_controllen = kcmlen;
return 0;
@ -225,7 +226,7 @@ Efault:
int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *data)
{
struct compat_cmsghdr __user *cm = (struct compat_cmsghdr __user *) kmsg->msg_control;
struct compat_cmsghdr __user *cm = (struct compat_cmsghdr __user *) kmsg->msg_control_user;
struct compat_cmsghdr cmhdr;
struct old_timeval32 ctv;
struct old_timespec32 cts[3];
@ -274,7 +275,7 @@ int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *dat
cmlen = CMSG_COMPAT_SPACE(len);
if (kmsg->msg_controllen < cmlen)
cmlen = kmsg->msg_controllen;
kmsg->msg_control += cmlen;
kmsg->msg_control_user += cmlen;
kmsg->msg_controllen -= cmlen;
return 0;
}
@ -289,7 +290,7 @@ static int scm_max_fds_compat(struct msghdr *msg)
void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm)
{
struct compat_cmsghdr __user *cm =
(struct compat_cmsghdr __user *)msg->msg_control;
(struct compat_cmsghdr __user *)msg->msg_control_user;
unsigned int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
int fdmax = min_t(int, scm_max_fds_compat(msg), scm->fp->count);
int __user *cmsg_data = CMSG_COMPAT_DATA(cm);
@ -313,7 +314,7 @@ void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm)
cmlen = CMSG_COMPAT_SPACE(i * sizeof(int));
if (msg->msg_controllen < cmlen)
cmlen = msg->msg_controllen;
msg->msg_control += cmlen;
msg->msg_control_user += cmlen;
msg->msg_controllen -= cmlen;
}
}

9
net/core/scm.c
View File

@ -250,7 +250,10 @@ int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data)
}
cmlen = min(CMSG_SPACE(len), msg->msg_controllen);
msg->msg_control += cmlen;
if (msg->msg_control_is_user)
msg->msg_control_user += cmlen;
else
msg->msg_control += cmlen;
msg->msg_controllen -= cmlen;
return 0;
@ -299,7 +302,7 @@ static int scm_max_fds(struct msghdr *msg)
void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
{
struct cmsghdr __user *cm =
(__force struct cmsghdr __user *)msg->msg_control;
(__force struct cmsghdr __user *)msg->msg_control_user;
unsigned int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
int fdmax = min_t(int, scm_max_fds(msg), scm->fp->count);
int __user *cmsg_data = CMSG_USER_DATA(cm);
@ -332,7 +335,7 @@ void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
cmlen = CMSG_SPACE(i * sizeof(int));
if (msg->msg_controllen < cmlen)
cmlen = msg->msg_controllen;
msg->msg_control += cmlen;
msg->msg_control_user += cmlen;
msg->msg_controllen -= cmlen;
}
}

4
net/ipv4/tcp.c
View File

@ -2165,7 +2165,7 @@ static void tcp_zc_finalize_rx_tstamp(struct sock *sk,
struct msghdr cmsg_dummy;
msg_control_addr = (unsigned long)zc->msg_control;
cmsg_dummy.msg_control = (void *)msg_control_addr;
cmsg_dummy.msg_control_user = (void __user *)msg_control_addr;
cmsg_dummy.msg_controllen =
(__kernel_size_t)zc->msg_controllen;
cmsg_dummy.msg_flags = in_compat_syscall()
@ -2176,7 +2176,7 @@ static void tcp_zc_finalize_rx_tstamp(struct sock *sk,
zc->msg_controllen == cmsg_dummy.msg_controllen) {
tcp_recv_timestamp(&cmsg_dummy, sk, tss);
zc->msg_control = (__u64)
((uintptr_t)cmsg_dummy.msg_control);
((uintptr_t)cmsg_dummy.msg_control_user);
zc->msg_controllen =
(__u64)cmsg_dummy.msg_controllen;
zc->msg_flags = (__u32)cmsg_dummy.msg_flags;

1
net/ipv6/ipv6_sockglue.c
View File

@ -716,6 +716,7 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
goto done;
msg.msg_controllen = optlen;
msg.msg_control_is_user = false;
msg.msg_control = (void *)(opt+1);
ipc6.opt = opt;