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authorArnd Bergmann <arnd@arndb.de>2021-07-22 17:28:59 +0300
committerDavid S. Miller <davem@davemloft.net>2021-07-23 16:20:25 +0300
commitdd98d2895de6485c884a9cb42de69fed02826fa4 (patch)
tree3cc4d41199502bb0013723b452709e6800b4994e /net/ethtool
parent1a33b18b3bd9748c9c712a23e788bf1f1c4a7025 (diff)
downloadlinux-dd98d2895de6485c884a9cb42de69fed02826fa4.tar.xz
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 84a1d9c48200 ("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>
Diffstat (limited to 'net/ethtool')
-rw-r--r--net/ethtool/ioctl.c136
1 files changed, 120 insertions, 16 deletions
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index baa5d10043cb..6134b180f59f 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -7,6 +7,7 @@
* the information ethtool needs.
*/
+#include <linux/compat.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/capability.h>
@@ -807,6 +808,120 @@ out:
return ret;
}
+static noinline_for_stack int
+ethtool_rxnfc_copy_from_compat(struct ethtool_rxnfc *rxnfc,
+ const struct compat_ethtool_rxnfc __user *useraddr,
+ size_t size)
+{
+ struct compat_ethtool_rxnfc crxnfc = {};
+
+ /* We expect there to be holes between fs.m_ext and
+ * fs.ring_cookie and at the end of fs, but nowhere else.
+ * On non-x86, no conversion should be needed.
+ */
+ BUILD_BUG_ON(!IS_ENABLED(CONFIG_X86_64) &&
+ sizeof(struct compat_ethtool_rxnfc) !=
+ sizeof(struct ethtool_rxnfc));
+ BUILD_BUG_ON(offsetof(struct compat_ethtool_rxnfc, fs.m_ext) +
+ sizeof(useraddr->fs.m_ext) !=
+ offsetof(struct ethtool_rxnfc, fs.m_ext) +
+ sizeof(rxnfc->fs.m_ext));
+ BUILD_BUG_ON(offsetof(struct compat_ethtool_rxnfc, fs.location) -
+ offsetof(struct compat_ethtool_rxnfc, fs.ring_cookie) !=
+ offsetof(struct ethtool_rxnfc, fs.location) -
+ offsetof(struct ethtool_rxnfc, fs.ring_cookie));
+
+ if (copy_from_user(&crxnfc, useraddr, min(size, sizeof(crxnfc))))
+ return -EFAULT;
+
+ *rxnfc = (struct ethtool_rxnfc) {
+ .cmd = crxnfc.cmd,
+ .flow_type = crxnfc.flow_type,
+ .data = crxnfc.data,
+ .fs = {
+ .flow_type = crxnfc.fs.flow_type,
+ .h_u = crxnfc.fs.h_u,
+ .h_ext = crxnfc.fs.h_ext,
+ .m_u = crxnfc.fs.m_u,
+ .m_ext = crxnfc.fs.m_ext,
+ .ring_cookie = crxnfc.fs.ring_cookie,
+ .location = crxnfc.fs.location,
+ },
+ .rule_cnt = crxnfc.rule_cnt,
+ };
+
+ return 0;
+}
+
+static int ethtool_rxnfc_copy_from_user(struct ethtool_rxnfc *rxnfc,
+ const void __user *useraddr,
+ size_t size)
+{
+ if (compat_need_64bit_alignment_fixup())
+ return ethtool_rxnfc_copy_from_compat(rxnfc, useraddr, size);
+
+ if (copy_from_user(rxnfc, useraddr, size))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int ethtool_rxnfc_copy_to_compat(void __user *useraddr,
+ const struct ethtool_rxnfc *rxnfc,
+ size_t size, const u32 *rule_buf)
+{
+ struct compat_ethtool_rxnfc crxnfc;
+
+ memset(&crxnfc, 0, sizeof(crxnfc));
+ crxnfc = (struct compat_ethtool_rxnfc) {
+ .cmd = rxnfc->cmd,
+ .flow_type = rxnfc->flow_type,
+ .data = rxnfc->data,
+ .fs = {
+ .flow_type = rxnfc->fs.flow_type,
+ .h_u = rxnfc->fs.h_u,
+ .h_ext = rxnfc->fs.h_ext,
+ .m_u = rxnfc->fs.m_u,
+ .m_ext = rxnfc->fs.m_ext,
+ .ring_cookie = rxnfc->fs.ring_cookie,
+ .location = rxnfc->fs.location,
+ },
+ .rule_cnt = rxnfc->rule_cnt,
+ };
+
+ if (copy_to_user(useraddr, &crxnfc, min(size, sizeof(crxnfc))))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int ethtool_rxnfc_copy_to_user(void __user *useraddr,
+ const struct ethtool_rxnfc *rxnfc,
+ size_t size, const u32 *rule_buf)
+{
+ int ret;
+
+ if (compat_need_64bit_alignment_fixup()) {
+ ret = ethtool_rxnfc_copy_to_compat(useraddr, rxnfc, size,
+ rule_buf);
+ useraddr += offsetof(struct compat_ethtool_rxnfc, rule_locs);
+ } else {
+ ret = copy_to_user(useraddr, &rxnfc, size);
+ useraddr += offsetof(struct ethtool_rxnfc, rule_locs);
+ }
+
+ if (ret)
+ return -EFAULT;
+
+ if (rule_buf) {
+ if (copy_to_user(useraddr, rule_buf,
+ rxnfc->rule_cnt * sizeof(u32)))
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
u32 cmd, void __user *useraddr)
{
@@ -825,7 +940,7 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
info_size = (offsetof(struct ethtool_rxnfc, data) +
sizeof(info.data));
- if (copy_from_user(&info, useraddr, info_size))
+ if (ethtool_rxnfc_copy_from_user(&info, useraddr, info_size))
return -EFAULT;
rc = dev->ethtool_ops->set_rxnfc(dev, &info);
@@ -833,7 +948,7 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
return rc;
if (cmd == ETHTOOL_SRXCLSRLINS &&
- copy_to_user(useraddr, &info, info_size))
+ ethtool_rxnfc_copy_to_user(useraddr, &info, info_size, NULL))
return -EFAULT;
return 0;
@@ -859,7 +974,7 @@ static noinline_for_stack int ethtool_get_rxnfc(struct net_device *dev,
info_size = (offsetof(struct ethtool_rxnfc, data) +
sizeof(info.data));
- if (copy_from_user(&info, useraddr, info_size))
+ if (ethtool_rxnfc_copy_from_user(&info, useraddr, info_size))
return -EFAULT;
/* If FLOW_RSS was requested then user-space must be using the
@@ -867,7 +982,7 @@ static noinline_for_stack int ethtool_get_rxnfc(struct net_device *dev,
*/
if (cmd == ETHTOOL_GRXFH && info.flow_type & FLOW_RSS) {
info_size = sizeof(info);
- if (copy_from_user(&info, useraddr, info_size))
+ if (ethtool_rxnfc_copy_from_user(&info, useraddr, info_size))
return -EFAULT;
/* Since malicious users may modify the original data,
* we need to check whether FLOW_RSS is still requested.
@@ -893,18 +1008,7 @@ static noinline_for_stack int ethtool_get_rxnfc(struct net_device *dev,
if (ret < 0)
goto err_out;
- ret = -EFAULT;
- if (copy_to_user(useraddr, &info, info_size))
- goto err_out;
-
- if (rule_buf) {
- useraddr += offsetof(struct ethtool_rxnfc, rule_locs);
- if (copy_to_user(useraddr, rule_buf,
- info.rule_cnt * sizeof(u32)))
- goto err_out;
- }
- ret = 0;
-
+ ret = ethtool_rxnfc_copy_to_user(useraddr, &info, info_size, rule_buf);
err_out:
kfree(rule_buf);