ethtool: improve compat ioctl handling
The ethtool compat ioctl handling is hidden away in net/socket.c,
which introduces a couple of minor oddities:
- The implementation may end up diverging, as seen in the RXNFC
extension in commit 84a1d9c482 ("net: ethtool: extend RXNFC
API to support RSS spreading of filter matches") that does not work
in compat mode.
- Most architectures do not need the compat handling at all
because u64 and compat_u64 have the same alignment.
- On x86, the conversion is done for both x32 and i386 user space,
but it's actually wrong to do it for x32 and cannot work there.
- On 32-bit Arm, it never worked for compat oabi user space, since
that needs to do the same conversion but does not.
- It would be nice to get rid of both compat_alloc_user_space()
and copy_in_user() throughout the kernel.
None of these actually seems to be a serious problem that real
users are likely to encounter, but fixing all of them actually
leads to code that is both shorter and more readable.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arnd Bergmann
David S. Miller
parent
1a33b18b3b
commit
dd98d2895d
@ -17,8 +17,6 @@
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#include <linux/compat.h>
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#include <uapi/linux/ethtool.h>
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#ifdef CONFIG_COMPAT
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struct compat_ethtool_rx_flow_spec {
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u32 flow_type;
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union ethtool_flow_union h_u;
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@ -38,8 +36,6 @@ struct compat_ethtool_rxnfc {
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u32 rule_locs[];
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};
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#endif /* CONFIG_COMPAT */
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#include <linux/rculist.h>
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/**
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@ -7,6 +7,7 @@
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* the information ethtool needs.
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*/
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#include <linux/compat.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/capability.h>
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@ -807,6 +808,120 @@ out:
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return ret;
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}
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static noinline_for_stack int
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ethtool_rxnfc_copy_from_compat(struct ethtool_rxnfc *rxnfc,
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const struct compat_ethtool_rxnfc __user *useraddr,
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size_t size)
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{
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struct compat_ethtool_rxnfc crxnfc = {};
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/* We expect there to be holes between fs.m_ext and
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* fs.ring_cookie and at the end of fs, but nowhere else.
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* On non-x86, no conversion should be needed.
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*/
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BUILD_BUG_ON(!IS_ENABLED(CONFIG_X86_64) &&
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sizeof(struct compat_ethtool_rxnfc) !=
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sizeof(struct ethtool_rxnfc));
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BUILD_BUG_ON(offsetof(struct compat_ethtool_rxnfc, fs.m_ext) +
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sizeof(useraddr->fs.m_ext) !=
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offsetof(struct ethtool_rxnfc, fs.m_ext) +
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sizeof(rxnfc->fs.m_ext));
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BUILD_BUG_ON(offsetof(struct compat_ethtool_rxnfc, fs.location) -
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offsetof(struct compat_ethtool_rxnfc, fs.ring_cookie) !=
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offsetof(struct ethtool_rxnfc, fs.location) -
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offsetof(struct ethtool_rxnfc, fs.ring_cookie));
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if (copy_from_user(&crxnfc, useraddr, min(size, sizeof(crxnfc))))
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return -EFAULT;
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*rxnfc = (struct ethtool_rxnfc) {
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.cmd = crxnfc.cmd,
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.flow_type = crxnfc.flow_type,
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.data = crxnfc.data,
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.fs = {
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.flow_type = crxnfc.fs.flow_type,
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.h_u = crxnfc.fs.h_u,
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.h_ext = crxnfc.fs.h_ext,
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.m_u = crxnfc.fs.m_u,
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.m_ext = crxnfc.fs.m_ext,
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.ring_cookie = crxnfc.fs.ring_cookie,
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.location = crxnfc.fs.location,
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},
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.rule_cnt = crxnfc.rule_cnt,
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};
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return 0;
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}
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static int ethtool_rxnfc_copy_from_user(struct ethtool_rxnfc *rxnfc,
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const void __user *useraddr,
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size_t size)
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{
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if (compat_need_64bit_alignment_fixup())
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return ethtool_rxnfc_copy_from_compat(rxnfc, useraddr, size);
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if (copy_from_user(rxnfc, useraddr, size))
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return -EFAULT;
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return 0;
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}
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static int ethtool_rxnfc_copy_to_compat(void __user *useraddr,
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const struct ethtool_rxnfc *rxnfc,
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size_t size, const u32 *rule_buf)
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{
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struct compat_ethtool_rxnfc crxnfc;
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memset(&crxnfc, 0, sizeof(crxnfc));
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crxnfc = (struct compat_ethtool_rxnfc) {
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.cmd = rxnfc->cmd,
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.flow_type = rxnfc->flow_type,
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.data = rxnfc->data,
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.fs = {
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.flow_type = rxnfc->fs.flow_type,
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.h_u = rxnfc->fs.h_u,
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.h_ext = rxnfc->fs.h_ext,
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.m_u = rxnfc->fs.m_u,
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.m_ext = rxnfc->fs.m_ext,
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.ring_cookie = rxnfc->fs.ring_cookie,
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.location = rxnfc->fs.location,
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},
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.rule_cnt = rxnfc->rule_cnt,
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};
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if (copy_to_user(useraddr, &crxnfc, min(size, sizeof(crxnfc))))
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return -EFAULT;
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return 0;
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}
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static int ethtool_rxnfc_copy_to_user(void __user *useraddr,
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const struct ethtool_rxnfc *rxnfc,
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size_t size, const u32 *rule_buf)
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{
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int ret;
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if (compat_need_64bit_alignment_fixup()) {
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ret = ethtool_rxnfc_copy_to_compat(useraddr, rxnfc, size,
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rule_buf);
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useraddr += offsetof(struct compat_ethtool_rxnfc, rule_locs);
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} else {
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ret = copy_to_user(useraddr, &rxnfc, size);
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useraddr += offsetof(struct ethtool_rxnfc, rule_locs);
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}
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if (ret)
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return -EFAULT;
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if (rule_buf) {
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if (copy_to_user(useraddr, rule_buf,
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rxnfc->rule_cnt * sizeof(u32)))
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return -EFAULT;
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}
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return 0;
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}
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static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
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u32 cmd, void __user *useraddr)
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{
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@ -825,7 +940,7 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
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info_size = (offsetof(struct ethtool_rxnfc, data) +
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sizeof(info.data));
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if (copy_from_user(&info, useraddr, info_size))
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if (ethtool_rxnfc_copy_from_user(&info, useraddr, info_size))
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return -EFAULT;
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rc = dev->ethtool_ops->set_rxnfc(dev, &info);
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@ -833,7 +948,7 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
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return rc;
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if (cmd == ETHTOOL_SRXCLSRLINS &&
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copy_to_user(useraddr, &info, info_size))
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ethtool_rxnfc_copy_to_user(useraddr, &info, info_size, NULL))
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return -EFAULT;
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return 0;
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@ -859,7 +974,7 @@ static noinline_for_stack int ethtool_get_rxnfc(struct net_device *dev,
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info_size = (offsetof(struct ethtool_rxnfc, data) +
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sizeof(info.data));
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if (copy_from_user(&info, useraddr, info_size))
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if (ethtool_rxnfc_copy_from_user(&info, useraddr, info_size))
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return -EFAULT;
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/* If FLOW_RSS was requested then user-space must be using the
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@ -867,7 +982,7 @@ static noinline_for_stack int ethtool_get_rxnfc(struct net_device *dev,
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*/
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if (cmd == ETHTOOL_GRXFH && info.flow_type & FLOW_RSS) {
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info_size = sizeof(info);
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if (copy_from_user(&info, useraddr, info_size))
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if (ethtool_rxnfc_copy_from_user(&info, useraddr, info_size))
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return -EFAULT;
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/* Since malicious users may modify the original data,
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* we need to check whether FLOW_RSS is still requested.
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@ -893,18 +1008,7 @@ static noinline_for_stack int ethtool_get_rxnfc(struct net_device *dev,
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if (ret < 0)
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goto err_out;
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ret = -EFAULT;
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if (copy_to_user(useraddr, &info, info_size))
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goto err_out;
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if (rule_buf) {
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useraddr += offsetof(struct ethtool_rxnfc, rule_locs);
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if (copy_to_user(useraddr, rule_buf,
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info.rule_cnt * sizeof(u32)))
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goto err_out;
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}
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ret = 0;
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ret = ethtool_rxnfc_copy_to_user(useraddr, &info, info_size, rule_buf);
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err_out:
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kfree(rule_buf);
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125
net/socket.c
125
net/socket.c
@ -3152,128 +3152,6 @@ static int compat_dev_ifconf(struct net *net, struct compat_ifconf __user *uifc3
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return 0;
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}
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static int ethtool_ioctl(struct net *net, struct compat_ifreq __user *ifr32)
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{
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struct compat_ethtool_rxnfc __user *compat_rxnfc;
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bool convert_in = false, convert_out = false;
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size_t buf_size = 0;
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struct ethtool_rxnfc __user *rxnfc = NULL;
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struct ifreq ifr;
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u32 rule_cnt = 0, actual_rule_cnt;
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u32 ethcmd;
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u32 data;
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int ret;
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if (get_user(data, &ifr32->ifr_ifru.ifru_data))
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return -EFAULT;
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compat_rxnfc = compat_ptr(data);
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if (get_user(ethcmd, &compat_rxnfc->cmd))
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return -EFAULT;
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/* Most ethtool structures are defined without padding.
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* Unfortunately struct ethtool_rxnfc is an exception.
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*/
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switch (ethcmd) {
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default:
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break;
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case ETHTOOL_GRXCLSRLALL:
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/* Buffer size is variable */
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if (get_user(rule_cnt, &compat_rxnfc->rule_cnt))
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return -EFAULT;
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if (rule_cnt > KMALLOC_MAX_SIZE / sizeof(u32))
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return -ENOMEM;
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buf_size += rule_cnt * sizeof(u32);
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fallthrough;
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case ETHTOOL_GRXRINGS:
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case ETHTOOL_GRXCLSRLCNT:
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case ETHTOOL_GRXCLSRULE:
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case ETHTOOL_SRXCLSRLINS:
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convert_out = true;
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fallthrough;
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case ETHTOOL_SRXCLSRLDEL:
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buf_size += sizeof(struct ethtool_rxnfc);
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convert_in = true;
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rxnfc = compat_alloc_user_space(buf_size);
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break;
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}
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if (copy_from_user(&ifr.ifr_name, &ifr32->ifr_name, IFNAMSIZ))
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return -EFAULT;
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ifr.ifr_data = convert_in ? rxnfc : (void __user *)compat_rxnfc;
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if (convert_in) {
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/* We expect there to be holes between fs.m_ext and
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* fs.ring_cookie and at the end of fs, but nowhere else.
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*/
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BUILD_BUG_ON(offsetof(struct compat_ethtool_rxnfc, fs.m_ext) +
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sizeof(compat_rxnfc->fs.m_ext) !=
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offsetof(struct ethtool_rxnfc, fs.m_ext) +
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sizeof(rxnfc->fs.m_ext));
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BUILD_BUG_ON(
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offsetof(struct compat_ethtool_rxnfc, fs.location) -
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offsetof(struct compat_ethtool_rxnfc, fs.ring_cookie) !=
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offsetof(struct ethtool_rxnfc, fs.location) -
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offsetof(struct ethtool_rxnfc, fs.ring_cookie));
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if (copy_in_user(rxnfc, compat_rxnfc,
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(void __user *)(&rxnfc->fs.m_ext + 1) -
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(void __user *)rxnfc) ||
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copy_in_user(&rxnfc->fs.ring_cookie,
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&compat_rxnfc->fs.ring_cookie,
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(void __user *)(&rxnfc->fs.location + 1) -
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(void __user *)&rxnfc->fs.ring_cookie))
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return -EFAULT;
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if (ethcmd == ETHTOOL_GRXCLSRLALL) {
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if (put_user(rule_cnt, &rxnfc->rule_cnt))
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return -EFAULT;
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} else if (copy_in_user(&rxnfc->rule_cnt,
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&compat_rxnfc->rule_cnt,
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sizeof(rxnfc->rule_cnt)))
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return -EFAULT;
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}
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ret = dev_ioctl(net, SIOCETHTOOL, &ifr, NULL);
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if (ret)
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return ret;
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if (convert_out) {
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if (copy_in_user(compat_rxnfc, rxnfc,
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(const void __user *)(&rxnfc->fs.m_ext + 1) -
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(const void __user *)rxnfc) ||
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copy_in_user(&compat_rxnfc->fs.ring_cookie,
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&rxnfc->fs.ring_cookie,
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(const void __user *)(&rxnfc->fs.location + 1) -
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(const void __user *)&rxnfc->fs.ring_cookie) ||
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copy_in_user(&compat_rxnfc->rule_cnt, &rxnfc->rule_cnt,
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sizeof(rxnfc->rule_cnt)))
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return -EFAULT;
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if (ethcmd == ETHTOOL_GRXCLSRLALL) {
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/* As an optimisation, we only copy the actual
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* number of rules that the underlying
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* function returned. Since Mallory might
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* change the rule count in user memory, we
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* check that it is less than the rule count
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* originally given (as the user buffer size),
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* which has been range-checked.
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*/
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if (get_user(actual_rule_cnt, &rxnfc->rule_cnt))
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return -EFAULT;
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if (actual_rule_cnt < rule_cnt)
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rule_cnt = actual_rule_cnt;
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if (copy_in_user(&compat_rxnfc->rule_locs[0],
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&rxnfc->rule_locs[0],
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rule_cnt * sizeof(u32)))
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return -EFAULT;
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}
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}
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return 0;
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}
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static int compat_siocwandev(struct net *net, struct compat_ifreq __user *uifr32)
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{
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compat_uptr_t uptr32;
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@ -3428,8 +3306,6 @@ static int compat_sock_ioctl_trans(struct file *file, struct socket *sock,
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return old_bridge_ioctl(argp);
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case SIOCGIFCONF:
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return compat_dev_ifconf(net, argp);
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case SIOCETHTOOL:
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return ethtool_ioctl(net, argp);
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case SIOCWANDEV:
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return compat_siocwandev(net, argp);
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case SIOCGIFMAP:
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@ -3442,6 +3318,7 @@ static int compat_sock_ioctl_trans(struct file *file, struct socket *sock,
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return sock->ops->gettstamp(sock, argp, cmd == SIOCGSTAMP_OLD,
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!COMPAT_USE_64BIT_TIME);
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case SIOCETHTOOL:
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case SIOCBONDSLAVEINFOQUERY:
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case SIOCBONDINFOQUERY:
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case SIOCSHWTSTAMP:
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