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authorEric Dumazet <edumazet@google.com>2016-06-27 19:51:53 +0300
committerDavid S. Miller <davem@davemloft.net>2016-07-01 11:02:55 +0300
commit19689e38eca5d7b32755182d4e62efd7a5376c45 (patch)
treebf400027c33a83030519e00b0c391e61e29a5566 /net/ipv4
parent435c556cde6096c2035207a5dceef1d99da51d01 (diff)
downloadlinux-19689e38eca5d7b32755182d4e62efd7a5376c45.tar.xz
tcp: md5: use kmalloc() backed scratch areas
Some arches have virtually mapped kernel stacks, or will soon have. tcp_md5_hash_header() uses an automatic variable to copy tcp header before mangling th->check and calling crypto function, which might be problematic on such arches. David says that using percpu storage is also problematic on non SMP builds. Just use kmalloc() to allocate scratch areas. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp.c10
-rw-r--r--net/ipv4/tcp_ipv4.c31
2 files changed, 24 insertions, 17 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 108ef2a6665c..032a96d78c99 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3026,8 +3026,18 @@ static void __tcp_alloc_md5sig_pool(void)
return;
for_each_possible_cpu(cpu) {
+ void *scratch = per_cpu(tcp_md5sig_pool, cpu).scratch;
struct ahash_request *req;
+ if (!scratch) {
+ scratch = kmalloc_node(sizeof(union tcp_md5sum_block) +
+ sizeof(struct tcphdr),
+ GFP_KERNEL,
+ cpu_to_node(cpu));
+ if (!scratch)
+ return;
+ per_cpu(tcp_md5sig_pool, cpu).scratch = scratch;
+ }
if (per_cpu(tcp_md5sig_pool, cpu).md5_req)
continue;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 3708de2a6683..32b048e524d6 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1018,27 +1018,28 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
GFP_KERNEL);
}
-static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
- __be32 daddr, __be32 saddr, int nbytes)
+static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
+ __be32 daddr, __be32 saddr,
+ const struct tcphdr *th, int nbytes)
{
struct tcp4_pseudohdr *bp;
struct scatterlist sg;
+ struct tcphdr *_th;
- bp = &hp->md5_blk.ip4;
-
- /*
- * 1. the TCP pseudo-header (in the order: source IP address,
- * destination IP address, zero-padded protocol number, and
- * segment length)
- */
+ bp = hp->scratch;
bp->saddr = saddr;
bp->daddr = daddr;
bp->pad = 0;
bp->protocol = IPPROTO_TCP;
bp->len = cpu_to_be16(nbytes);
- sg_init_one(&sg, bp, sizeof(*bp));
- ahash_request_set_crypt(hp->md5_req, &sg, NULL, sizeof(*bp));
+ _th = (struct tcphdr *)(bp + 1);
+ memcpy(_th, th, sizeof(*th));
+ _th->check = 0;
+
+ sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th));
+ ahash_request_set_crypt(hp->md5_req, &sg, NULL,
+ sizeof(*bp) + sizeof(*th));
return crypto_ahash_update(hp->md5_req);
}
@@ -1055,9 +1056,7 @@ static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
if (crypto_ahash_init(req))
goto clear_hash;
- if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
- goto clear_hash;
- if (tcp_md5_hash_header(hp, th))
+ if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2))
goto clear_hash;
if (tcp_md5_hash_key(hp, key))
goto clear_hash;
@@ -1101,9 +1100,7 @@ int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
if (crypto_ahash_init(req))
goto clear_hash;
- if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
- goto clear_hash;
- if (tcp_md5_hash_header(hp, th))
+ if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len))
goto clear_hash;
if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
goto clear_hash;