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netfilter: nf_flow_table_offload: Correct memcpy size for flow_overlo…
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…ad_mangle()

In function 'memcpy',
     inlined from 'flow_offload_mangle' at net/netfilter/nf_flow_table_offload.c:112:2,
     inlined from 'flow_offload_port_dnat' at net/netfilter/nf_flow_table_offload.c:373:2,
     inlined from 'nf_flow_rule_route_ipv4' at net/netfilter/nf_flow_table_offload.c:424:3:
./include/linux/string.h:376:4: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter
   376 |    __read_overflow2();
       |    ^~~~~~~~~~~~~~~~~~

The original u8* was done in the hope to make this more adaptable but
consensus is to keep this like it is in tc pedit.

Fixes: c29f74e ("netfilter: nf_flow_table: hardware offload support")
Reported-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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@ummakynes
ummakynes committed Dec 9, 2019
1 parent 5604285 commit 7acd937
Showing 1 changed file with 28 additions and 31 deletions.
59 changes: 28 additions & 31 deletions net/netfilter/nf_flow_table_offload.c
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Original file line number Diff line number Diff line change
Expand Up @@ -112,8 +112,8 @@ static int nf_flow_rule_match(struct nf_flow_match *match,
}

static void flow_offload_mangle(struct flow_action_entry *entry,
enum flow_action_mangle_base htype,
u32 offset, u8 *value, u8 *mask)
enum flow_action_mangle_base htype, u32 offset,
const __be32 *value, const __be32 *mask)
{
entry->id = FLOW_ACTION_MANGLE;
entry->mangle.htype = htype;
Expand Down Expand Up @@ -150,12 +150,12 @@ static int flow_offload_eth_src(struct net *net,
memcpy(&val16, dev->dev_addr, 2);
val = val16 << 16;
flow_offload_mangle(entry0, FLOW_ACT_MANGLE_HDR_TYPE_ETH, 4,
(u8 *)&val, (u8 *)&mask);
&val, &mask);

mask = ~0xffffffff;
memcpy(&val, dev->dev_addr + 2, 4);
flow_offload_mangle(entry1, FLOW_ACT_MANGLE_HDR_TYPE_ETH, 8,
(u8 *)&val, (u8 *)&mask);
&val, &mask);
dev_put(dev);

return 0;
Expand All @@ -180,13 +180,13 @@ static int flow_offload_eth_dst(struct net *net,
mask = ~0xffffffff;
memcpy(&val, n->ha, 4);
flow_offload_mangle(entry0, FLOW_ACT_MANGLE_HDR_TYPE_ETH, 0,
(u8 *)&val, (u8 *)&mask);
&val, &mask);

mask = ~0x0000ffff;
memcpy(&val16, n->ha + 4, 2);
val = val16;
flow_offload_mangle(entry1, FLOW_ACT_MANGLE_HDR_TYPE_ETH, 4,
(u8 *)&val, (u8 *)&mask);
&val, &mask);
neigh_release(n);

return 0;
Expand Down Expand Up @@ -216,7 +216,7 @@ static void flow_offload_ipv4_snat(struct net *net,
}

flow_offload_mangle(entry, FLOW_ACT_MANGLE_HDR_TYPE_IP4, offset,
(u8 *)&addr, (u8 *)&mask);
&addr, &mask);
}

static void flow_offload_ipv4_dnat(struct net *net,
Expand All @@ -243,21 +243,20 @@ static void flow_offload_ipv4_dnat(struct net *net,
}

flow_offload_mangle(entry, FLOW_ACT_MANGLE_HDR_TYPE_IP4, offset,
(u8 *)&addr, (u8 *)&mask);
&addr, &mask);
}

static void flow_offload_ipv6_mangle(struct nf_flow_rule *flow_rule,
unsigned int offset,
u8 *addr, u8 *mask)
const __be32 *addr, const __be32 *mask)
{
struct flow_action_entry *entry;
int i;

for (i = 0; i < sizeof(struct in6_addr) / sizeof(u32); i += sizeof(u32)) {
entry = flow_action_entry_next(flow_rule);
flow_offload_mangle(entry, FLOW_ACT_MANGLE_HDR_TYPE_IP6,
offset + i,
&addr[i], mask);
offset + i, &addr[i], mask);
}
}

Expand All @@ -267,23 +266,23 @@ static void flow_offload_ipv6_snat(struct net *net,
struct nf_flow_rule *flow_rule)
{
u32 mask = ~htonl(0xffffffff);
const u8 *addr;
const __be32 *addr;
u32 offset;

switch (dir) {
case FLOW_OFFLOAD_DIR_ORIGINAL:
addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v6.s6_addr;
addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v6.s6_addr32;
offset = offsetof(struct ipv6hdr, saddr);
break;
case FLOW_OFFLOAD_DIR_REPLY:
addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v6.s6_addr;
addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v6.s6_addr32;
offset = offsetof(struct ipv6hdr, daddr);
break;
default:
return;
}

flow_offload_ipv6_mangle(flow_rule, offset, (u8 *)addr, (u8 *)&mask);
flow_offload_ipv6_mangle(flow_rule, offset, addr, &mask);
}

static void flow_offload_ipv6_dnat(struct net *net,
Expand All @@ -292,23 +291,23 @@ static void flow_offload_ipv6_dnat(struct net *net,
struct nf_flow_rule *flow_rule)
{
u32 mask = ~htonl(0xffffffff);
const u8 *addr;
const __be32 *addr;
u32 offset;

switch (dir) {
case FLOW_OFFLOAD_DIR_ORIGINAL:
addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v6.s6_addr;
addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v6.s6_addr32;
offset = offsetof(struct ipv6hdr, daddr);
break;
case FLOW_OFFLOAD_DIR_REPLY:
addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v6.s6_addr;
addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v6.s6_addr32;
offset = offsetof(struct ipv6hdr, saddr);
break;
default:
return;
}

flow_offload_ipv6_mangle(flow_rule, offset, (u8 *)addr, (u8 *)&mask);
flow_offload_ipv6_mangle(flow_rule, offset, addr, &mask);
}

static int flow_offload_l4proto(const struct flow_offload *flow)
Expand Down Expand Up @@ -336,25 +335,24 @@ static void flow_offload_port_snat(struct net *net,
struct nf_flow_rule *flow_rule)
{
struct flow_action_entry *entry = flow_action_entry_next(flow_rule);
u32 mask = ~htonl(0xffff0000);
__be16 port;
u32 mask = ~htonl(0xffff0000), port;
u32 offset;

switch (dir) {
case FLOW_OFFLOAD_DIR_ORIGINAL:
port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port;
port = ntohs(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port);
offset = 0; /* offsetof(struct tcphdr, source); */
break;
case FLOW_OFFLOAD_DIR_REPLY:
port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port;
port = ntohs(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port);
offset = 0; /* offsetof(struct tcphdr, dest); */
break;
default:
return;
}

port = htonl(port << 16);
flow_offload_mangle(entry, flow_offload_l4proto(flow), offset,
(u8 *)&port, (u8 *)&mask);
&port, &mask);
}

static void flow_offload_port_dnat(struct net *net,
Expand All @@ -363,25 +361,24 @@ static void flow_offload_port_dnat(struct net *net,
struct nf_flow_rule *flow_rule)
{
struct flow_action_entry *entry = flow_action_entry_next(flow_rule);
u32 mask = ~htonl(0xffff);
__be16 port;
u32 mask = ~htonl(0xffff), port;
u32 offset;

switch (dir) {
case FLOW_OFFLOAD_DIR_ORIGINAL:
port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port;
port = ntohs(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port);
offset = 0; /* offsetof(struct tcphdr, source); */
break;
case FLOW_OFFLOAD_DIR_REPLY:
port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port;
port = ntohs(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port);
offset = 0; /* offsetof(struct tcphdr, dest); */
break;
default:
return;
}

port = htonl(port);
flow_offload_mangle(entry, flow_offload_l4proto(flow), offset,
(u8 *)&port, (u8 *)&mask);
&port, &mask);
}

static void flow_offload_ipv4_checksum(struct net *net,
Expand Down

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