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Sat, 04 Apr 2026 02:06:21 -0700 (PDT) Received: from Raptor-X102-mclgxx ([93.175.1.46]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5a2c6ccdefcsm1957236e87.68.2026.04.04.02.06.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 04 Apr 2026 02:06:20 -0700 (PDT) From: Kotlyarov Mihail To: netdev@vger.kernel.org Cc: Kotlyarov Mihail , lvc-project@linuxtesting.org, steffen.klassert@secunet.com, herbert@gondor.apana.org.au, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, fw@strlen.de, linux-kernel@vger.kernel.org Subject: [PATCH ipsec] xfrm: fix refcount leak in xfrm_migrate_policy_find Date: Sat, 4 Apr 2026 12:05:20 +0300 Message-ID: <20260404090525.105083-1-mihailkotlyarow@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit syzkaller reported a memory leak in xfrm_policy_alloc: BUG: memory leak unreferenced object 0xffff888114d79000 (size 1024): comm "syz.1.17", pid 931 ... xfrm_policy_alloc+0xb3/0x4b0 net/xfrm/xfrm_policy.c:432 The root cause is a double call to xfrm_pol_hold_rcu() in xfrm_migrate_policy_find(). The lookup function already returns a policy with held reference, making the second call redundant. Remove the redundant xfrm_pol_hold_rcu() call to fix the refcount imbalance and prevent the memory leak. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: 563d5ca93e88 ("xfrm: switch migrate to xfrm_policy_lookup_bytype") Signed-off-by: Kotlyarov Mihail --- net/xfrm/xfrm_policy.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 62486f866975..8566bc464668 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -4517,9 +4517,6 @@ static struct xfrm_policy *xfrm_migrate_policy_find(const struct xfrm_selector * pol = xfrm_policy_lookup_bytype(net, type, &fl, sel->family, dir, if_id); if (IS_ERR_OR_NULL(pol)) goto out_unlock; - - if (!xfrm_pol_hold_rcu(pol)) - pol = NULL; out_unlock: rcu_read_unlock(); return pol; -- 2.53.0