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| author | Maxim Mikityanskiy <maximmi@nvidia.com> | 2022-05-12 12:18:30 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-05-12 10:01:36 -0700 |
| commit | 3740651bf7e200109dd42d5b2fb22226b26f960a (patch) | |
| tree | 642623aed22f6d728acd0e129891856c10cdfcac /net | |
| parent | 1fa89ffbc04545b7582518e57f4b63e2a062870f (diff) | |
| download | linux-3740651bf7e200109dd42d5b2fb22226b26f960a.tar.gz linux-3740651bf7e200109dd42d5b2fb22226b26f960a.tar.bz2 linux-3740651bf7e200109dd42d5b2fb22226b26f960a.zip | |
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.c | 3 |
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); |