6.17-stable review patch. If anyone has any objections, please let me know.
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From: Kuniyuki Iwashima kuniyu@google.com
[ Upstream commit 935d783e5de9b64587f3adb25641dd8385e64ddb ]
smc_clc_prfx_set() is called during connect() and not under RCU nor RTNL.
Using sk_dst_get(sk)->dev could trigger UAF.
Let's use __sk_dst_get() and dev_dst_rcu() under rcu_read_lock() after kernel_getsockname().
Note that the returned value of smc_clc_prfx_set() is not used in the caller.
While at it, we change the 1st arg of smc_clc_prfx_set[46]_rcu() not to touch dst there.
Fixes: a046d57da19f ("smc: CLC handshake (incl. preparation steps)") Signed-off-by: Kuniyuki Iwashima kuniyu@google.com Reviewed-by: Eric Dumazet edumazet@google.com Link: https://patch.msgid.link/20250916214758.650211-3-kuniyu@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/smc/smc_clc.c | 41 ++++++++++++++++++++++------------------- 1 file changed, 22 insertions(+), 19 deletions(-)
diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c index 08be56dfb3f24..976b2102bdfcd 100644 --- a/net/smc/smc_clc.c +++ b/net/smc/smc_clc.c @@ -509,10 +509,10 @@ static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm, bool check_trl) }
/* find ipv4 addr on device and get the prefix len, fill CLC proposal msg */ -static int smc_clc_prfx_set4_rcu(struct dst_entry *dst, __be32 ipv4, +static int smc_clc_prfx_set4_rcu(struct net_device *dev, __be32 ipv4, struct smc_clc_msg_proposal_prefix *prop) { - struct in_device *in_dev = __in_dev_get_rcu(dst->dev); + struct in_device *in_dev = __in_dev_get_rcu(dev); const struct in_ifaddr *ifa;
if (!in_dev) @@ -530,12 +530,12 @@ static int smc_clc_prfx_set4_rcu(struct dst_entry *dst, __be32 ipv4, }
/* fill CLC proposal msg with ipv6 prefixes from device */ -static int smc_clc_prfx_set6_rcu(struct dst_entry *dst, +static int smc_clc_prfx_set6_rcu(struct net_device *dev, struct smc_clc_msg_proposal_prefix *prop, struct smc_clc_ipv6_prefix *ipv6_prfx) { #if IS_ENABLED(CONFIG_IPV6) - struct inet6_dev *in6_dev = __in6_dev_get(dst->dev); + struct inet6_dev *in6_dev = __in6_dev_get(dev); struct inet6_ifaddr *ifa; int cnt = 0;
@@ -564,41 +564,44 @@ static int smc_clc_prfx_set(struct socket *clcsock, struct smc_clc_msg_proposal_prefix *prop, struct smc_clc_ipv6_prefix *ipv6_prfx) { - struct dst_entry *dst = sk_dst_get(clcsock->sk); struct sockaddr_storage addrs; struct sockaddr_in6 *addr6; struct sockaddr_in *addr; + struct net_device *dev; + struct dst_entry *dst; int rc = -ENOENT;
- if (!dst) { - rc = -ENOTCONN; - goto out; - } - if (!dst->dev) { - rc = -ENODEV; - goto out_rel; - } /* get address to which the internal TCP socket is bound */ if (kernel_getsockname(clcsock, (struct sockaddr *)&addrs) < 0) - goto out_rel; + goto out; + /* analyze IP specific data of net_device belonging to TCP socket */ addr6 = (struct sockaddr_in6 *)&addrs; + rcu_read_lock(); + + dst = __sk_dst_get(clcsock->sk); + dev = dst ? dst_dev_rcu(dst) : NULL; + if (!dev) { + rc = -ENODEV; + goto out_unlock; + } + if (addrs.ss_family == PF_INET) { /* IPv4 */ addr = (struct sockaddr_in *)&addrs; - rc = smc_clc_prfx_set4_rcu(dst, addr->sin_addr.s_addr, prop); + rc = smc_clc_prfx_set4_rcu(dev, addr->sin_addr.s_addr, prop); } else if (ipv6_addr_v4mapped(&addr6->sin6_addr)) { /* mapped IPv4 address - peer is IPv4 only */ - rc = smc_clc_prfx_set4_rcu(dst, addr6->sin6_addr.s6_addr32[3], + rc = smc_clc_prfx_set4_rcu(dev, addr6->sin6_addr.s6_addr32[3], prop); } else { /* IPv6 */ - rc = smc_clc_prfx_set6_rcu(dst, prop, ipv6_prfx); + rc = smc_clc_prfx_set6_rcu(dev, prop, ipv6_prfx); } + +out_unlock: rcu_read_unlock(); -out_rel: - dst_release(dst); out: return rc; }