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authorEric Dumazet <edumazet@google.com>2016-06-27 18:51:53 +0200
committerDavid S. Miller <davem@davemloft.net>2016-07-01 04:02:55 -0400
commit19689e38eca5d7b32755182d4e62efd7a5376c45 (patch)
treebf400027c33a83030519e00b0c391e61e29a5566 /net/ipv4/tcp.c
parent435c556cde6096c2035207a5dceef1d99da51d01 (diff)
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/tcp.c')
-rw-r--r--net/ipv4/tcp.c10
1 files changed, 10 insertions, 0 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;