Since smc_inet6_prot does not initialize ipv6_pinfo_offset, inet6_create()
copies an incorrect address value, sk + 0 (offset), to inet_sk(sk)->pinet6.
In addition, since inet_sk(sk)->pinet6 and smc_sk(sk)->clcsock practically
point to the same address, when smc_create_clcsk() stores the newly
created clcsock in smc_sk(sk)->clcsock, inet_sk(sk)->pinet6 is corrupted
into clcsock. This causes NULL pointer dereference and various other
memory corruptions.
To solve this problem, you need to initialize ipv6_pinfo_offset, add a
smc6_sock structure, and then add ipv6_pinfo as the second member of
the smc_sock structure.
Reported-by: syzkaller <syzkaller@xxxxxxxxxxxxxxxx>
Fixes: d25a92ccae6b ("net/smc: Introduce IPPROTO_SMC")
Signed-off-by: Jeongjun Park <aha310510@xxxxxxxxx>
---
net/smc/smc.h | 3 +++
net/smc/smc_inet.c | 8 +++++++-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/net/smc/smc.h b/net/smc/smc.h
index 34b781e463c4..ad77d6b6b8d3 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -284,6 +284,9 @@ struct smc_connection {
struct smc_sock { /* smc sock container */
struct sock sk;
+#if IS_ENABLED(CONFIG_IPV6)
+ struct ipv6_pinfo *pinet6;
+#endif
struct socket *clcsock; /* internal tcp socket */
void (*clcsk_state_change)(struct sock *sk);
/* original stat_change fct. */
diff --git a/net/smc/smc_inet.c b/net/smc/smc_inet.c
index bece346dd8e9..a5b2041600f9 100644
--- a/net/smc/smc_inet.c
+++ b/net/smc/smc_inet.c
@@ -60,6 +60,11 @@ static struct inet_protosw smc_inet_protosw = {
};
#if IS_ENABLED(CONFIG_IPV6)
+struct smc6_sock {
+ struct smc_sock smc;
+ struct ipv6_pinfo inet6;
+};
+
static struct proto smc_inet6_prot = {
.name = "INET6_SMC",
.owner = THIS_MODULE,
@@ -67,9 +72,10 @@ static struct proto smc_inet6_prot = {
.hash = smc_hash_sk,
.unhash = smc_unhash_sk,
.release_cb = smc_release_cb,
- .obj_size = sizeof(struct smc_sock),
+ .obj_size = sizeof(struct smc6_sock),
.h.smc_hash = &smc_v6_hashinfo,
.slab_flags = SLAB_TYPESAFE_BY_RCU,
+ .ipv6_pinfo_offset = offsetof(struct smc6_sock, inet6),
};
static const struct proto_ops smc_inet6_stream_ops = {
--
