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authorMaxim Mikityanskiy <maximmi@nvidia.com>2022-05-12 12:18:30 +0300
committerJakub Kicinski <kuba@kernel.org>2022-05-12 10:01:36 -0700
commit3740651bf7e200109dd42d5b2fb22226b26f960a (patch)
tree642623aed22f6d728acd0e129891856c10cdfcac /net
parent1fa89ffbc04545b7582518e57f4b63e2a062870f (diff)
tls: Fix context leak on tls_device_down
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>
Diffstat (limited to 'net')
-rw-r--r--net/tls/tls_device.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index af875ad4a822..3919fe2c58c5 100644
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -1347,7 +1347,10 @@ 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);