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Fri, 24 Jul 2026 14:47:03 -0700 (PDT) From: Fredric Cover To: sfrench@samba.org Cc: pc@manguebit.org, ronniesahlberg@gmail.com, sprasad@microsoft.com, tom@talpey.com, bharathsm@microsoft.com, linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org, Fredric Cover , stable@vger.kernel.org Subject: [PATCH v2 2/2] smb: client: clear ce->tgthint in free_tgts() Date: Fri, 24 Jul 2026 14:44:35 -0700 Message-ID: <20260724214435.1850384-3-fredric.cover.lkernel@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260724214435.1850384-1-fredric.cover.lkernel@gmail.com> References: <20260724023539.1596955-1-fredric.cover.lkernel@gmail.com> <20260724214435.1850384-1-fredric.cover.lkernel@gmail.com> Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When free_tgts() frees all structures in ce->tlist, ce->tgthint is left pointing to one of the freed cache_dfs_tgt structures. If ce->tgthint is not reset before it is used later, it results in a use-after-free. Set ce->tgthint to NULL in free_tgts() after the elements are freed to reflect that no elements remain. Fixes: 54be1f6c1c37 ("cifs: Add DFS cache routines") Cc: stable@vger.kernel.org # depends on: smb: client: harden DFS cache against invalid target hints Signed-off-by: Fredric Cover --- fs/smb/client/dfs_cache.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/smb/client/dfs_cache.c b/fs/smb/client/dfs_cache.c index c9ace4326a35..86dba25b7a5a 100644 --- a/fs/smb/client/dfs_cache.c +++ b/fs/smb/client/dfs_cache.c @@ -122,6 +122,8 @@ static inline void free_tgts(struct cache_entry *ce) kfree(t->name); kfree(t); } + + WRITE_ONCE(ce->tgthint, NULL); } static inline void flush_cache_ent(struct cache_entry *ce) -- 2.53.0