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net/smc: prevent NULL pointer dereference in txopt_get

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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@googlegroups.com>
Fixes: d25a92ccae ("net/smc: Introduce IPPROTO_SMC")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jeongjun Park 2024-08-29 12:56:48 +09:00 committed by David S. Miller
parent 1bb3c548e4
commit 98d4435efc
2 changed files with 10 additions and 1 deletions
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3
net/smc/smc.h
View File

@ -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. */

8
net/smc/smc_inet.c
View File

@ -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 = {