lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

tcp: fix MD5 (RFC2385) support

Browse Source 
TCP MD5 support uses percpu data for temporary storage. It currently
disables preemption so that same storage cannot be reclaimed by another
thread on same cpu.

We also have to make sure a softirq handler wont try to use also same
context. Various bug reports demonstrated corruptions.

Fix is to disable preemption and BH.

Reported-by: Bhaskar Dutta <bhaskie@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2010-05-16 00:34:04 -07:00
committed by David S. Miller
parent d77f873fdd
commit 35790c0421
2 changed files with 27 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
net/ipv4/tcp.c
View File

@@ -2839,7 +2839,6 @@ static void __tcp_free_md5sig_pool(struct tcp_md5sig_pool * __percpu *pool)
if (p->md5_desc.tfm)
crypto_free_hash(p->md5_desc.tfm);
kfree(p);
p = NULL;
}
}
free_percpu(pool);
@@ -2937,25 +2936,40 @@ retry:
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)
/**
* tcp_get_md5sig_pool - get md5sig_pool for this user
*
* We use percpu structure, so if we succeed, we exit with preemption
* and BH disabled, to make sure another thread or softirq handling
* wont try to get same context.
*/
struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
{
struct tcp_md5sig_pool * __percpu *p;
spin_lock_bh(&tcp_md5sig_pool_lock);
local_bh_disable();
spin_lock(&tcp_md5sig_pool_lock);
p = tcp_md5sig_pool;
if (p)
tcp_md5sig_users++;
spin_unlock_bh(&tcp_md5sig_pool_lock);
return (p ? *per_cpu_ptr(p, cpu) : NULL);
spin_unlock(&tcp_md5sig_pool_lock);
if (p)
return *per_cpu_ptr(p, smp_processor_id());
local_bh_enable();
return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
EXPORT_SYMBOL(__tcp_get_md5sig_pool);
void __tcp_put_md5sig_pool(void)
void tcp_put_md5sig_pool(void)
{
local_bh_enable();
tcp_free_md5sig_pool();
}
EXPORT_SYMBOL(__tcp_put_md5sig_pool);
EXPORT_SYMBOL(tcp_put_md5sig_pool);
int tcp_md5_hash_header(struct tcp_md5sig_pool *hp,
struct tcphdr *th)