| Message ID | 20250305-mptcp-tcp-ulp-diag-cap-v2-2-d53fd80748eb@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 61da849b89369c2e7beb1218cb7071014d7d20e7 |
| Delegated to: | Matthieu Baerts |
| Headers | show |
| Series | tcp: ulp: diag: remove net admin restriction | expand |
| Context | Check | Description |
|---|---|---|
| matttbe/build | success | Build and static analysis OK |
| matttbe/checkpatch | warning | total: 0 errors, 6 warnings, 0 checks, 122 lines checked |
| matttbe/shellcheck | success | MPTCP selftests files have not been modified |
| matttbe/KVM_Validation__normal | success | Success! ✅ |
| matttbe/KVM_Validation__debug | success | Success! ✅ |
| matttbe/KVM_Validation__btf-normal__only_bpftest_all_ | success | Success! ✅ |
| matttbe/KVM_Validation__btf-debug__only_bpftest_all_ | success | Success! ✅ |
On Wed, 5 Mar 2025, Matthieu Baerts (NGI0) wrote: > When introduced in commit 61723b393292 ("tcp: ulp: add functions to dump > ulp-specific information"), the whole ULP diag info has been exported > only if the requester had CAP_NET_ADMIN. > > It looks like not everything is sensitive, and some info can be exported > to all users in order to ease the debugging from the userspace side > without requiring additional capabilities. Each layer should then decide > what can be exposed to everybody. The 'net_admin' boolean is then passed > to the different layers. > > On kTLS side, it looks like there is nothing sensitive there, only some > metadata about the configuration, no cryptographic information. Then, > everything can be exported to all users. > > On MPTCP side, that's different. The MPTCP-related sequence numbers per > subflow should certainly not be exposed to everybody. For example, the > DSS mapping and ssn_offset would give all users on the system access to > narrow ranges of values for the subflow TCP sequence numbers and > MPTCP-level DSNs, and then ease packet injection. The TCP diag interface > doesn't expose the TCP sequence numbers for TCP sockets, so best to do > the same here. > > Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> > --- > include/net/tcp.h | 4 ++-- > net/ipv4/tcp_diag.c | 8 ++++---- > net/mptcp/diag.c | 42 ++++++++++++++++++++++++++---------------- > net/tls/tls_main.c | 4 ++-- > 4 files changed, 34 insertions(+), 24 deletions(-) Matthieu - This patch also LGTM: Acked-by: Mat Martineau <martineau@kernel.org> > > diff --git a/include/net/tcp.h b/include/net/tcp.h > index a9bc959fb102fc6697b4a664b3773b47b3309f13..7207c52b1fc9ce3cd9cf2a8580310d0e629f82d6 100644 > --- a/include/net/tcp.h > +++ b/include/net/tcp.h > @@ -2598,8 +2598,8 @@ struct tcp_ulp_ops { > /* cleanup ulp */ > void (*release)(struct sock *sk); > /* diagnostic */ > - int (*get_info)(struct sock *sk, struct sk_buff *skb); > - size_t (*get_info_size)(const struct sock *sk); > + int (*get_info)(struct sock *sk, struct sk_buff *skb, bool net_admin); > + size_t (*get_info_size)(const struct sock *sk, bool net_admin); > /* clone ulp */ > void (*clone)(const struct request_sock *req, struct sock *newsk, > const gfp_t priority); > diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c > index d8bba37dbffd8c6cc7fab2328a88b6ce6ea3e9f4..45e174b8cd22173b6b8eeffe71df334c45498b15 100644 > --- a/net/ipv4/tcp_diag.c > +++ b/net/ipv4/tcp_diag.c > @@ -96,8 +96,8 @@ static int tcp_diag_put_ulp(struct sk_buff *skb, struct sock *sk, > if (err) > goto nla_failure; > > - if (net_admin && ulp_ops->get_info) > - err = ulp_ops->get_info(sk, skb); > + if (ulp_ops->get_info) > + err = ulp_ops->get_info(sk, skb, net_admin); > if (err) > goto nla_failure; > > @@ -170,8 +170,8 @@ static size_t tcp_diag_get_aux_size(struct sock *sk, bool net_admin) > if (ulp_ops) { > size += nla_total_size(0) + > nla_total_size(TCP_ULP_NAME_MAX); > - if (net_admin && ulp_ops->get_info_size) > - size += ulp_ops->get_info_size(sk); > + if (ulp_ops->get_info_size) > + size += ulp_ops->get_info_size(sk, net_admin); > } > } > return size; > diff --git a/net/mptcp/diag.c b/net/mptcp/diag.c > index 02205f7994d752cc505991efdf7aa0bbbfd830db..70cf9ebce8338bde3b0bb10fc8620905b15f5190 100644 > --- a/net/mptcp/diag.c > +++ b/net/mptcp/diag.c > @@ -12,7 +12,7 @@ > #include <net/netlink.h> > #include "protocol.h" > > -static int subflow_get_info(struct sock *sk, struct sk_buff *skb) > +static int subflow_get_info(struct sock *sk, struct sk_buff *skb, bool net_admin) > { > struct mptcp_subflow_context *sf; > struct nlattr *start; > @@ -56,15 +56,6 @@ static int subflow_get_info(struct sock *sk, struct sk_buff *skb) > > if (nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_TOKEN_REM, sf->remote_token) || > nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_TOKEN_LOC, sf->token) || > - nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ, > - sf->rel_write_seq) || > - nla_put_u64_64bit(skb, MPTCP_SUBFLOW_ATTR_MAP_SEQ, sf->map_seq, > - MPTCP_SUBFLOW_ATTR_PAD) || > - nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_MAP_SFSEQ, > - sf->map_subflow_seq) || > - nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_SSN_OFFSET, sf->ssn_offset) || > - nla_put_u16(skb, MPTCP_SUBFLOW_ATTR_MAP_DATALEN, > - sf->map_data_len) || > nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_FLAGS, flags) || > nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_REM, sf->remote_id) || > nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_LOC, subflow_get_local_id(sf))) { > @@ -72,6 +63,21 @@ static int subflow_get_info(struct sock *sk, struct sk_buff *skb) > goto nla_failure; > } > > + /* Only export seq related counters to user with CAP_NET_ADMIN */ > + if (net_admin && > + (nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ, > + sf->rel_write_seq) || > + nla_put_u64_64bit(skb, MPTCP_SUBFLOW_ATTR_MAP_SEQ, sf->map_seq, > + MPTCP_SUBFLOW_ATTR_PAD) || > + nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_MAP_SFSEQ, > + sf->map_subflow_seq) || > + nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_SSN_OFFSET, sf->ssn_offset) || > + nla_put_u16(skb, MPTCP_SUBFLOW_ATTR_MAP_DATALEN, > + sf->map_data_len))) { > + err = -EMSGSIZE; > + goto nla_failure; > + } > + > rcu_read_unlock(); > unlock_sock_fast(sk, slow); > nla_nest_end(skb, start); > @@ -84,22 +90,26 @@ static int subflow_get_info(struct sock *sk, struct sk_buff *skb) > return err; > } > > -static size_t subflow_get_info_size(const struct sock *sk) > +static size_t subflow_get_info_size(const struct sock *sk, bool net_admin) > { > size_t size = 0; > > size += nla_total_size(0) + /* INET_ULP_INFO_MPTCP */ > nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_TOKEN_REM */ > nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_TOKEN_LOC */ > - nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */ > - nla_total_size_64bit(8) + /* MPTCP_SUBFLOW_ATTR_MAP_SEQ */ > - nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */ > - nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */ > - nla_total_size(2) + /* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */ > nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_FLAGS */ > nla_total_size(1) + /* MPTCP_SUBFLOW_ATTR_ID_REM */ > nla_total_size(1) + /* MPTCP_SUBFLOW_ATTR_ID_LOC */ > 0; > + > + if (net_admin) > + size += nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */ > + nla_total_size_64bit(8) + /* MPTCP_SUBFLOW_ATTR_MAP_SEQ */ > + nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */ > + nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */ > + nla_total_size(2) + /* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */ > + 0; > + > return size; > } > > diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c > index 99ca4465f70216c5a44e4ca7477df0e93df6b76d..cb86b0bf9a53e1ff060d8e69eddbd6acfbee5194 100644 > --- a/net/tls/tls_main.c > +++ b/net/tls/tls_main.c > @@ -1057,7 +1057,7 @@ static u16 tls_user_config(struct tls_context *ctx, bool tx) > return 0; > } > > -static int tls_get_info(struct sock *sk, struct sk_buff *skb) > +static int tls_get_info(struct sock *sk, struct sk_buff *skb, bool net_admin) > { > u16 version, cipher_type; > struct tls_context *ctx; > @@ -1115,7 +1115,7 @@ static int tls_get_info(struct sock *sk, struct sk_buff *skb) > return err; > } > > -static size_t tls_get_info_size(const struct sock *sk) > +static size_t tls_get_info_size(const struct sock *sk, bool net_admin) > { > size_t size = 0; > > > -- > 2.47.1 > >
diff --git a/include/net/tcp.h b/include/net/tcp.h index a9bc959fb102fc6697b4a664b3773b47b3309f13..7207c52b1fc9ce3cd9cf2a8580310d0e629f82d6 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2598,8 +2598,8 @@ struct tcp_ulp_ops { /* cleanup ulp */ void (*release)(struct sock *sk); /* diagnostic */ - int (*get_info)(struct sock *sk, struct sk_buff *skb); - size_t (*get_info_size)(const struct sock *sk); + int (*get_info)(struct sock *sk, struct sk_buff *skb, bool net_admin); + size_t (*get_info_size)(const struct sock *sk, bool net_admin); /* clone ulp */ void (*clone)(const struct request_sock *req, struct sock *newsk, const gfp_t priority); diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c index d8bba37dbffd8c6cc7fab2328a88b6ce6ea3e9f4..45e174b8cd22173b6b8eeffe71df334c45498b15 100644 --- a/net/ipv4/tcp_diag.c +++ b/net/ipv4/tcp_diag.c @@ -96,8 +96,8 @@ static int tcp_diag_put_ulp(struct sk_buff *skb, struct sock *sk, if (err) goto nla_failure; - if (net_admin && ulp_ops->get_info) - err = ulp_ops->get_info(sk, skb); + if (ulp_ops->get_info) + err = ulp_ops->get_info(sk, skb, net_admin); if (err) goto nla_failure; @@ -170,8 +170,8 @@ static size_t tcp_diag_get_aux_size(struct sock *sk, bool net_admin) if (ulp_ops) { size += nla_total_size(0) + nla_total_size(TCP_ULP_NAME_MAX); - if (net_admin && ulp_ops->get_info_size) - size += ulp_ops->get_info_size(sk); + if (ulp_ops->get_info_size) + size += ulp_ops->get_info_size(sk, net_admin); } } return size; diff --git a/net/mptcp/diag.c b/net/mptcp/diag.c index 02205f7994d752cc505991efdf7aa0bbbfd830db..70cf9ebce8338bde3b0bb10fc8620905b15f5190 100644 --- a/net/mptcp/diag.c +++ b/net/mptcp/diag.c @@ -12,7 +12,7 @@ #include <net/netlink.h> #include "protocol.h" -static int subflow_get_info(struct sock *sk, struct sk_buff *skb) +static int subflow_get_info(struct sock *sk, struct sk_buff *skb, bool net_admin) { struct mptcp_subflow_context *sf; struct nlattr *start; @@ -56,15 +56,6 @@ static int subflow_get_info(struct sock *sk, struct sk_buff *skb) if (nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_TOKEN_REM, sf->remote_token) || nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_TOKEN_LOC, sf->token) || - nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ, - sf->rel_write_seq) || - nla_put_u64_64bit(skb, MPTCP_SUBFLOW_ATTR_MAP_SEQ, sf->map_seq, - MPTCP_SUBFLOW_ATTR_PAD) || - nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_MAP_SFSEQ, - sf->map_subflow_seq) || - nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_SSN_OFFSET, sf->ssn_offset) || - nla_put_u16(skb, MPTCP_SUBFLOW_ATTR_MAP_DATALEN, - sf->map_data_len) || nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_FLAGS, flags) || nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_REM, sf->remote_id) || nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_LOC, subflow_get_local_id(sf))) { @@ -72,6 +63,21 @@ static int subflow_get_info(struct sock *sk, struct sk_buff *skb) goto nla_failure; } + /* Only export seq related counters to user with CAP_NET_ADMIN */ + if (net_admin && + (nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ, + sf->rel_write_seq) || + nla_put_u64_64bit(skb, MPTCP_SUBFLOW_ATTR_MAP_SEQ, sf->map_seq, + MPTCP_SUBFLOW_ATTR_PAD) || + nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_MAP_SFSEQ, + sf->map_subflow_seq) || + nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_SSN_OFFSET, sf->ssn_offset) || + nla_put_u16(skb, MPTCP_SUBFLOW_ATTR_MAP_DATALEN, + sf->map_data_len))) { + err = -EMSGSIZE; + goto nla_failure; + } + rcu_read_unlock(); unlock_sock_fast(sk, slow); nla_nest_end(skb, start); @@ -84,22 +90,26 @@ static int subflow_get_info(struct sock *sk, struct sk_buff *skb) return err; } -static size_t subflow_get_info_size(const struct sock *sk) +static size_t subflow_get_info_size(const struct sock *sk, bool net_admin) { size_t size = 0; size += nla_total_size(0) + /* INET_ULP_INFO_MPTCP */ nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_TOKEN_REM */ nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_TOKEN_LOC */ - nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */ - nla_total_size_64bit(8) + /* MPTCP_SUBFLOW_ATTR_MAP_SEQ */ - nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */ - nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */ - nla_total_size(2) + /* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */ nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_FLAGS */ nla_total_size(1) + /* MPTCP_SUBFLOW_ATTR_ID_REM */ nla_total_size(1) + /* MPTCP_SUBFLOW_ATTR_ID_LOC */ 0; + + if (net_admin) + size += nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */ + nla_total_size_64bit(8) + /* MPTCP_SUBFLOW_ATTR_MAP_SEQ */ + nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */ + nla_total_size(4) + /* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */ + nla_total_size(2) + /* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */ + 0; + return size; } diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c index 99ca4465f70216c5a44e4ca7477df0e93df6b76d..cb86b0bf9a53e1ff060d8e69eddbd6acfbee5194 100644 --- a/net/tls/tls_main.c +++ b/net/tls/tls_main.c @@ -1057,7 +1057,7 @@ static u16 tls_user_config(struct tls_context *ctx, bool tx) return 0; } -static int tls_get_info(struct sock *sk, struct sk_buff *skb) +static int tls_get_info(struct sock *sk, struct sk_buff *skb, bool net_admin) { u16 version, cipher_type; struct tls_context *ctx; @@ -1115,7 +1115,7 @@ static int tls_get_info(struct sock *sk, struct sk_buff *skb) return err; } -static size_t tls_get_info_size(const struct sock *sk) +static size_t tls_get_info_size(const struct sock *sk, bool net_admin) { size_t size = 0;
When introduced in commit 61723b393292 ("tcp: ulp: add functions to dump ulp-specific information"), the whole ULP diag info has been exported only if the requester had CAP_NET_ADMIN. It looks like not everything is sensitive, and some info can be exported to all users in order to ease the debugging from the userspace side without requiring additional capabilities. Each layer should then decide what can be exposed to everybody. The 'net_admin' boolean is then passed to the different layers. On kTLS side, it looks like there is nothing sensitive there, only some metadata about the configuration, no cryptographic information. Then, everything can be exported to all users. On MPTCP side, that's different. The MPTCP-related sequence numbers per subflow should certainly not be exposed to everybody. For example, the DSS mapping and ssn_offset would give all users on the system access to narrow ranges of values for the subflow TCP sequence numbers and MPTCP-level DSNs, and then ease packet injection. The TCP diag interface doesn't expose the TCP sequence numbers for TCP sockets, so best to do the same here. Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> --- include/net/tcp.h | 4 ++-- net/ipv4/tcp_diag.c | 8 ++++---- net/mptcp/diag.c | 42 ++++++++++++++++++++++++++---------------- net/tls/tls_main.c | 4 ++-- 4 files changed, 34 insertions(+), 24 deletions(-)