Re: [PATCH 19/26] net/ipv6: switch ipv6_flowlabel_opt to sockptr_t

Christoph Hellwig
2020-07-27T16:15:55Z

I have to admit I didn't spot the difference between the good and the
bad output even after trying hard..

But can you try the patch below?

---
From cce2d2e1b43ecee5f4af7cf116808b74b330080f Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 27 Jul 2020 17:42:27 +0200
Subject: net: remove sockptr_advance

sockptr_advance never properly worked. Replace it with _offset variants
of copy_from_sockptr and copy_to_sockptr.

Fixes: ba423fdaa589 ("net: add a new sockptr_t type")
Reported-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reported-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/crypto/chelsio/chtls/chtls_main.c | 12 +++++-----
include/linux/sockptr.h | 27 +++++++++++------------
net/dccp/proto.c | 5 ++---
net/ipv4/netfilter/arp_tables.c | 8 +++----
net/ipv4/netfilter/ip_tables.c | 8 +++----
net/ipv4/tcp.c | 5 +++--
net/ipv6/ip6_flowlabel.c | 11 ++++-----
net/ipv6/netfilter/ip6_tables.c | 8 +++----
net/netfilter/x_tables.c | 7 +++---
net/tls/tls_main.c | 6 ++---
10 files changed, 49 insertions(+), 48 deletions(-)

diff --git a/drivers/crypto/chelsio/chtls/chtls_main.c b/drivers/crypto/chelsio/chtls/chtls_main.c
index c3058dcdb33c5c..66d247efd5615b 100644
--- a/drivers/crypto/chelsio/chtls/chtls_main.c
+++ b/drivers/crypto/chelsio/chtls/chtls_main.c
@@ -525,9 +525,9 @@ static int do_chtls_setsockopt(struct sock *sk, int optname,
/* Obtain version and type from previous copy */
crypto_info[0] = tmp_crypto_info;
/* Now copy the following data */
- sockptr_advance(optval, sizeof(*crypto_info));
- rc = copy_from_sockptr((char *)crypto_info + sizeof(*crypto_info),
- optval,
+ rc = copy_from_sockptr_offset((char *)crypto_info +
+ sizeof(*crypto_info),
+ optval, sizeof(*crypto_info),
sizeof(struct tls12_crypto_info_aes_gcm_128)
- sizeof(*crypto_info));

@@ -542,9 +542,9 @@ static int do_chtls_setsockopt(struct sock *sk, int optname,
}
case TLS_CIPHER_AES_GCM_256: {
crypto_info[0] = tmp_crypto_info;
- sockptr_advance(optval, sizeof(*crypto_info));
- rc = copy_from_sockptr((char *)crypto_info + sizeof(*crypto_info),
- optval,
+ rc = copy_from_sockptr_offset((char *)crypto_info +
+ sizeof(*crypto_info),
+ optval, sizeof(*crypto_info),
sizeof(struct tls12_crypto_info_aes_gcm_256)
- sizeof(*crypto_info));

diff --git a/include/linux/sockptr.h b/include/linux/sockptr.h
index b13ea1422f93a5..9e6c81d474cba8 100644
--- a/include/linux/sockptr.h
+++ b/include/linux/sockptr.h
@@ -69,19 +69,26 @@ static inline bool sockptr_is_null(sockptr_t sockptr)
return !sockptr.user;
}

-static inline int copy_from_sockptr(void *dst, sockptr_t src, size_t size)
+static inline int copy_from_sockptr_offset(void *dst, sockptr_t src,
+ size_t offset, size_t size)
{
if (!sockptr_is_kernel(src))
- return copy_from_user(dst, src.user, size);
- memcpy(dst, src.kernel, size);
+ return copy_from_user(dst, src.user + offset, size);
+ memcpy(dst, src.kernel + offset, size);
return 0;
}

-static inline int copy_to_sockptr(sockptr_t dst, const void *src, size_t size)
+static inline int copy_from_sockptr(void *dst, sockptr_t src, size_t size)
+{
+ return copy_from_sockptr_offset(dst, src, 0, size);
+}
+
+static inline int copy_to_sockptr_offset(sockptr_t dst, size_t offset,
+ const void *src, size_t size)
{
if (!sockptr_is_kernel(dst))
- return copy_to_user(dst.user, src, size);
- memcpy(dst.kernel, src, size);
+ return copy_to_user(dst.user + offset, src, size);
+ memcpy(dst.kernel + offset, src, size);
return 0;
}

@@ -112,14 +119,6 @@ static inline void *memdup_sockptr_nul(sockptr_t src, size_t len)
return p;
}

-static inline void sockptr_advance(sockptr_t sockptr, size_t len)
-{
- if (sockptr_is_kernel(sockptr))
- sockptr.kernel += len;
- else
- sockptr.user += len;
-}
-
static inline long strncpy_from_sockptr(char *dst, sockptr_t src, size_t count)
{
if (sockptr_is_kernel(src)) {
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 2e9e8449698fb4..d148ab1530e57b 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -426,9 +426,8 @@ static int dccp_setsockopt_service(struct sock *sk, const __be32 service,
return -ENOMEM;

sl->dccpsl_nr = optlen / sizeof(u32) - 1;
- sockptr_advance(optval, sizeof(service));
- if (copy_from_sockptr(sl->dccpsl_list, optval,
- optlen - sizeof(service)) ||
+ if (copy_from_sockptr_offset(sl->dccpsl_list, optval,
+ sizeof(service), optlen - sizeof(service)) ||
dccp_list_has_service(sl, DCCP_SERVICE_INVALID_VALUE)) {
kfree(sl);
return -EFAULT;
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 9a1567dbc022b6..d1e04d2b5170ec 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -971,8 +971,8 @@ static int do_replace(struct net *net, sockptr_t arg, unsigned int len)
return -ENOMEM;

loc_cpu_entry = newinfo->entries;
- sockptr_advance(arg, sizeof(tmp));
- if (copy_from_sockptr(loc_cpu_entry, arg, tmp.size) != 0) {
+ if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
+ tmp.size) != 0) {
ret = -EFAULT;
goto free_newinfo;
}
@@ -1267,8 +1267,8 @@ static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
return -ENOMEM;

loc_cpu_entry = newinfo->entries;
- sockptr_advance(arg, sizeof(tmp));
- if (copy_from_sockptr(loc_cpu_entry, arg, tmp.size) != 0) {
+ if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
+ tmp.size) != 0) {
ret = -EFAULT;
goto free_newinfo;
}
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index f2a9680303d8c0..f15bc21d730164 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1126,8 +1126,8 @@ do_replace(struct net *net, sockptr_t arg, unsigned int len)
return -ENOMEM;

loc_cpu_entry = newinfo->entries;
- sockptr_advance(arg, sizeof(tmp));
- if (copy_from_sockptr(loc_cpu_entry, arg, tmp.size) != 0) {
+ if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
+ tmp.size) != 0) {
ret = -EFAULT;
goto free_newinfo;
}
@@ -1508,8 +1508,8 @@ compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
return -ENOMEM;

loc_cpu_entry = newinfo->entries;
- sockptr_advance(arg, sizeof(tmp));
- if (copy_from_sockptr(loc_cpu_entry, arg, tmp.size) != 0) {
+ if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
+ tmp.size) != 0) {
ret = -EFAULT;
goto free_newinfo;
}
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 27de9380ed140e..4afec552f211b9 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2801,12 +2801,13 @@ static int tcp_repair_options_est(struct sock *sk, sockptr_t optbuf,
{
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_repair_opt opt;
+ size_t offset = 0;

while (len >= sizeof(opt)) {
- if (copy_from_sockptr(&opt, optbuf, sizeof(opt)))
+ if (copy_from_sockptr_offset(&opt, optbuf, offset, sizeof(opt)))
return -EFAULT;

- sockptr_advance(optbuf, sizeof(opt));
+ offset += sizeof(opt);
len -= sizeof(opt);

switch (opt.opt_code) {
diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index 215b6f5e733ec9..2d655260dedc75 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -401,8 +401,8 @@ fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
memset(fl->opt, 0, sizeof(*fl->opt));
fl->opt->tot_len = sizeof(*fl->opt) + olen;
err = -EFAULT;
- sockptr_advance(optval, CMSG_ALIGN(sizeof(*freq)));
- if (copy_from_sockptr(fl->opt + 1, optval, olen))
+ if (copy_from_sockptr_offset(fl->opt + 1, optval,
+ CMSG_ALIGN(sizeof(*freq)), olen))
goto done;

msg.msg_controllen = olen;
@@ -703,9 +703,10 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
goto recheck;

if (!freq->flr_label) {
- sockptr_advance(optval,
- offsetof(struct in6_flowlabel_req, flr_label));
- if (copy_to_sockptr(optval, &fl->label, sizeof(fl->label))) {
+ size_t offset = offsetof(struct in6_flowlabel_req, flr_label);
+
+ if (copy_to_sockptr_offset(optval, offset, &fl->label,
+ sizeof(fl->label))) {
/* Intentionally ignore fault. */
}
}
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 1d52957a413f4a..2e2119bfcf1373 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1143,8 +1143,8 @@ do_replace(struct net *net, sockptr_t arg, unsigned int len)
return -ENOMEM;

loc_cpu_entry = newinfo->entries;
- sockptr_advance(arg, sizeof(tmp));
- if (copy_from_sockptr(loc_cpu_entry, arg, tmp.size) != 0) {
+ if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
+ tmp.size) != 0) {
ret = -EFAULT;
goto free_newinfo;
}
@@ -1517,8 +1517,8 @@ compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
return -ENOMEM;

loc_cpu_entry = newinfo->entries;
- sockptr_advance(arg, sizeof(tmp));
- if (copy_from_sockptr(loc_cpu_entry, arg, tmp.size) != 0) {
+ if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
+ tmp.size) != 0) {
ret = -EFAULT;
goto free_newinfo;
}
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index b97eb4b538fd4e..91bf6635ea9ee4 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1050,6 +1050,7 @@ EXPORT_SYMBOL_GPL(xt_check_target);
void *xt_copy_counters(sockptr_t arg, unsigned int len,
struct xt_counters_info *info)
{
+ size_t offset;
void *mem;
u64 size;

@@ -1067,7 +1068,7 @@ void *xt_copy_counters(sockptr_t arg, unsigned int len,

memcpy(info->name, compat_tmp.name, sizeof(info->name) - 1);
info->num_counters = compat_tmp.num_counters;
- sockptr_advance(arg, sizeof(compat_tmp));
+ offset = sizeof(compat_tmp);
} else
#endif
{
@@ -1078,7 +1079,7 @@ void *xt_copy_counters(sockptr_t arg, unsigned int len,
if (copy_from_sockptr(info, arg, sizeof(*info)) != 0)
return ERR_PTR(-EFAULT);

- sockptr_advance(arg, sizeof(*info));
+ offset = sizeof(*info);
}
info->name[sizeof(info->name) - 1] = '\0';

@@ -1092,7 +1093,7 @@ void *xt_copy_counters(sockptr_t arg, unsigned int len,
if (!mem)
return ERR_PTR(-ENOMEM);

- if (copy_from_sockptr(mem, arg, len) = 0)
+ if (copy_from_sockptr_offset(mem, arg, offset, len) = 0)
return mem;

vfree(mem);
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index d77f7d821130db..bbc52b088d2968 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -522,9 +522,9 @@ static int do_tls_setsockopt_conf(struct sock *sk, sockptr_t optval,
goto err_crypto_info;
}

- sockptr_advance(optval, sizeof(*crypto_info));
- rc = copy_from_sockptr(crypto_info + 1, optval,
- optlen - sizeof(*crypto_info));
+ rc = copy_from_sockptr_offset(crypto_info + 1, optval,
+ sizeof(*crypto_info),
+ optlen - sizeof(*crypto_info));
if (rc) {
rc = -EFAULT;
goto err_crypto_info;
--
2.27.0