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| author | Al Viro <viro@zeniv.linux.org.uk> | 2017-06-26 20:19:16 +0300 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2018-01-25 03:13:45 +0300 |
| commit | 36fd633ec98acd2028585c22128fcaa3da6d5770 (patch) | |
| tree | 1fa77e8bf1662dea936b52107a0d39485110edb1 /net/core/dev_ioctl.c | |
| parent | be1b6e8b5470e8311bfa1a3dfd7bd59e85a99759 (diff) | |
| download | linux-36fd633ec98acd2028585c22128fcaa3da6d5770.tar.xz | |
net: separate SIOCGIFCONF handling from dev_ioctl()
Only two of dev_ioctl() callers may pass SIOCGIFCONF to it.
Separating that codepath from the rest of dev_ioctl() allows both
to simplify dev_ioctl() itself (all other cases work with struct ifreq *)
*and* seriously simplify the compat side of that beast: all it takes
is passing to inet_gifconf() an extra argument - the size of individual
records (sizeof(struct ifreq) or sizeof(struct compat_ifreq)). With
dev_ifconf() called directly from sock_do_ioctl()/compat_dev_ifconf()
that's easy to arrange.
As the result, compat side of SIOCGIFCONF doesn't need any
allocations, copy_in_user() back and forth, etc.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'net/core/dev_ioctl.c')
| -rw-r--r-- | net/core/dev_ioctl.c | 29 |
1 files changed, 7 insertions, 22 deletions
diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c index 7e690d0ccd05..5cdec23dd28e 100644 --- a/net/core/dev_ioctl.c +++ b/net/core/dev_ioctl.c @@ -66,9 +66,8 @@ EXPORT_SYMBOL(register_gifconf); * Thus we will need a 'compatibility mode'. */ -static int dev_ifconf(struct net *net, char __user *arg) +int dev_ifconf(struct net *net, struct ifconf *ifc, int size) { - struct ifconf ifc; struct net_device *dev; char __user *pos; int len; @@ -79,11 +78,8 @@ static int dev_ifconf(struct net *net, char __user *arg) * Fetch the caller's info block. */ - if (copy_from_user(&ifc, arg, sizeof(struct ifconf))) - return -EFAULT; - - pos = ifc.ifc_buf; - len = ifc.ifc_len; + pos = ifc->ifc_buf; + len = ifc->ifc_len; /* * Loop over the interfaces, and write an info block for each. @@ -95,10 +91,10 @@ static int dev_ifconf(struct net *net, char __user *arg) if (gifconf_list[i]) { int done; if (!pos) - done = gifconf_list[i](dev, NULL, 0); + done = gifconf_list[i](dev, NULL, 0, size); else done = gifconf_list[i](dev, pos + total, - len - total); + len - total, size); if (done < 0) return -EFAULT; total += done; @@ -109,12 +105,12 @@ static int dev_ifconf(struct net *net, char __user *arg) /* * All done. Write the updated control block back to the caller. */ - ifc.ifc_len = total; + ifc->ifc_len = total; /* * Both BSD and Solaris return 0 here, so we do too. */ - return copy_to_user(arg, &ifc, sizeof(struct ifconf)) ? -EFAULT : 0; + return 0; } /* @@ -412,17 +408,6 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg) int ret; char *colon; - /* One special case: SIOCGIFCONF takes ifconf argument - and requires shared lock, because it sleeps writing - to user space. - */ - - if (cmd == SIOCGIFCONF) { - rtnl_lock(); - ret = dev_ifconf(net, (char __user *) arg); - rtnl_unlock(); - return ret; - } if (cmd == SIOCGIFNAME) return dev_ifname(net, (struct ifreq __user *)arg); |