diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2022-02-02 14:20:31 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-02-04 10:14:07 +0000 |
| commit | b93235e68921b9acd38ee309953a3a9808105289 (patch) | |
| tree | 48d9273feaf831aaa0b4f3393c199a049505b1f6 /net/tls | |
| parent | 6ff6064605e96db40c7e95c4924518028cd827bf (diff) | |
tls: cap the output scatter list to something reasonable
TLS recvmsg() passes user pages as destination for decrypt.
The decrypt operation is repeated record by record, each
record being 16kB, max. TLS allocates an sg_table and uses
iov_iter_get_pages() to populate it with enough pages to
fit the decrypted record.
Even though we decrypt a single message at a time we size
the sg_table based on the entire length of the iovec.
This leads to unnecessarily large allocations, risking
triggering OOM conditions.
Use iov_iter_truncate() / iov_iter_reexpand() to construct
a "capped" version of iov_iter_npages(). Alternatively we
could parametrize iov_iter_npages() to take the size as
arg instead of using i->count, or do something else..
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tls')
| -rw-r--r-- | net/tls/tls_sw.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index efc84845bb6b..0024a692f0f8 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1433,7 +1433,8 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb, if (*zc && (out_iov || out_sg)) { if (out_iov) - n_sgout = iov_iter_npages(out_iov, INT_MAX) + 1; + n_sgout = 1 + + iov_iter_npages_cap(out_iov, INT_MAX, data_len); else n_sgout = sg_nents(out_sg); n_sgin = skb_nsg(skb, rxm->offset + prot->prepend_size, |