diff mbox series

[net-next,4/6] inet: annotate data-races around ifa->ifa_flags

Message ID 20240229114016.2995906-5-edumazet@google.com (mailing list archive)
State Accepted
Commit 3ddc2231c8108302a8229d3c5849ee792a63230d
Delegated to: Netdev Maintainers
Headers show
Series inet: no longer use RTNL to protect inet_dump_ifaddr() | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 942 this patch: 942
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 958 this patch: 958
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 959 this patch: 959
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 77 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-03-01--06-00 (tests: 882)

Commit Message

Eric Dumazet Feb. 29, 2024, 11:40 a.m. UTC 
ifa->ifa_flags can be read locklessly.

Add appropriate READ_ONCE()/WRITE_ONCE() annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/devinet.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 368fb56e1f1b2e3b7888f611a3f113f3bd5fc2af..550b775cbbf3c140c66e224c69996df7051b3d36 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -716,8 +716,10 @@  static void check_lifetime(struct work_struct *work)
 			unsigned long age, tstamp;
 			u32 preferred_lft;
 			u32 valid_lft;
+			u32 flags;
 
-			if (ifa->ifa_flags & IFA_F_PERMANENT)
+			flags = READ_ONCE(ifa->ifa_flags);
+			if (flags & IFA_F_PERMANENT)
 				continue;
 
 			preferred_lft = READ_ONCE(ifa->ifa_preferred_lft);
@@ -737,7 +739,7 @@  static void check_lifetime(struct work_struct *work)
 				if (time_before(tstamp + valid_lft * HZ, next))
 					next = tstamp + valid_lft * HZ;
 
-				if (!(ifa->ifa_flags & IFA_F_DEPRECATED))
+				if (!(flags & IFA_F_DEPRECATED))
 					change_needed = true;
 			} else if (time_before(tstamp + preferred_lft * HZ,
 					       next)) {
@@ -805,21 +807,23 @@  static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft,
 			     __u32 prefered_lft)
 {
 	unsigned long timeout;
+	u32 flags;
 
-	ifa->ifa_flags &= ~(IFA_F_PERMANENT | IFA_F_DEPRECATED);
+	flags = ifa->ifa_flags & ~(IFA_F_PERMANENT | IFA_F_DEPRECATED);
 
 	timeout = addrconf_timeout_fixup(valid_lft, HZ);
 	if (addrconf_finite_timeout(timeout))
 		WRITE_ONCE(ifa->ifa_valid_lft, timeout);
 	else
-		ifa->ifa_flags |= IFA_F_PERMANENT;
+		flags |= IFA_F_PERMANENT;
 
 	timeout = addrconf_timeout_fixup(prefered_lft, HZ);
 	if (addrconf_finite_timeout(timeout)) {
 		if (timeout == 0)
-			ifa->ifa_flags |= IFA_F_DEPRECATED;
+			flags |= IFA_F_DEPRECATED;
 		WRITE_ONCE(ifa->ifa_preferred_lft, timeout);
 	}
+	WRITE_ONCE(ifa->ifa_flags, flags);
 	WRITE_ONCE(ifa->ifa_tstamp, jiffies);
 	if (!ifa->ifa_cstamp)
 		WRITE_ONCE(ifa->ifa_cstamp, ifa->ifa_tstamp);
@@ -1313,7 +1317,7 @@  static __be32 in_dev_select_addr(const struct in_device *in_dev,
 	const struct in_ifaddr *ifa;
 
 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
-		if (ifa->ifa_flags & IFA_F_SECONDARY)
+		if (READ_ONCE(ifa->ifa_flags) & IFA_F_SECONDARY)
 			continue;
 		if (ifa->ifa_scope != RT_SCOPE_LINK &&
 		    ifa->ifa_scope <= scope)
@@ -1341,7 +1345,7 @@  __be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope)
 		localnet_scope = RT_SCOPE_LINK;
 
 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
-		if (ifa->ifa_flags & IFA_F_SECONDARY)
+		if (READ_ONCE(ifa->ifa_flags) & IFA_F_SECONDARY)
 			continue;
 		if (min(ifa->ifa_scope, localnet_scope) > scope)
 			continue;
@@ -1688,7 +1692,7 @@  static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
 	ifm = nlmsg_data(nlh);
 	ifm->ifa_family = AF_INET;
 	ifm->ifa_prefixlen = ifa->ifa_prefixlen;
-	ifm->ifa_flags = ifa->ifa_flags;
+	ifm->ifa_flags = READ_ONCE(ifa->ifa_flags);
 	ifm->ifa_scope = ifa->ifa_scope;
 	ifm->ifa_index = ifa->ifa_dev->dev->ifindex;
 
@@ -1728,7 +1732,7 @@  static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
 	     nla_put_string(skb, IFA_LABEL, ifa->ifa_label)) ||
 	    (ifa->ifa_proto &&
 	     nla_put_u8(skb, IFA_PROTO, ifa->ifa_proto)) ||
-	    nla_put_u32(skb, IFA_FLAGS, ifa->ifa_flags) ||
+	    nla_put_u32(skb, IFA_FLAGS, ifm->ifa_flags) ||
 	    (ifa->ifa_rt_priority &&
 	     nla_put_u32(skb, IFA_RT_PRIORITY, ifa->ifa_rt_priority)) ||
 	    put_cacheinfo(skb, READ_ONCE(ifa->ifa_cstamp), tstamp,