diff options
| author | Maxim Mikityanskiy <maximmi@nvidia.com> | 2022-05-12 12:18:30 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-18 11:23:45 +0300 |
| commit | fccf4bf3f25dff4aa47d80926298f3707b8d1072 (patch) | |
| tree | f3029a7720b0e517783aedefa641afbe419bb5fa /net/tls | |
| parent | 161c4edeca45a1b24a589693efbc639ecf850c20 (diff) | |
| download | linux-fccf4bf3f25dff4aa47d80926298f3707b8d1072.tar.xz | |
tls: Fix context leak on tls_device_down
[ Upstream commit 3740651bf7e200109dd42d5b2fb22226b26f960a ]
The commit cited below claims to fix a use-after-free condition after
tls_device_down. Apparently, the description wasn't fully accurate. The
context stayed alive, but ctx->netdev became NULL, and the offload was
torn down without a proper fallback, so a bug was present, but a
different kind of bug.
Due to misunderstanding of the issue, the original patch dropped the
refcount_dec_and_test line for the context to avoid the alleged
premature deallocation. That line has to be restored, because it matches
the refcount_inc_not_zero from the same function, otherwise the contexts
that survived tls_device_down are leaked.
This patch fixes the described issue by restoring refcount_dec_and_test.
After this change, there is no leak anymore, and the fallback to
software kTLS still works.
Fixes: c55dcdd435aa ("net/tls: Fix use-after-free after the TLS device goes down and up")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20220512091830.678684-1-maximmi@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/tls')
| -rw-r--r-- | net/tls/tls_device.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c index 1f56225a10e3..3c82286e5bcc 100644 --- a/net/tls/tls_device.c +++ b/net/tls/tls_device.c @@ -1345,7 +1345,10 @@ static int tls_device_down(struct net_device *netdev) /* Device contexts for RX and TX will be freed in on sk_destruct * by tls_device_free_ctx. rx_conf and tx_conf stay in TLS_HW. + * Now release the ref taken above. */ + if (refcount_dec_and_test(&ctx->refcount)) + tls_device_free_ctx(ctx); } up_write(&device_offload_lock); |