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Wed, 26 Aug 2026 12:10:56 -0700 (PDT) From: Fredric Cover To: Paulo Alcantara , Namjae Jeon Cc: ChenXiaoSong , Tom Talpey , Ronnie Sahlberg , Shyam Prasad N , Bharath SM , linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org, Fredric Cover Subject: [PATCH 2/2] smb: client: prevent out-of-bounds dfs_info3_param access in copy_ref_data() Date: Wed, 26 Aug 2026 12:10:33 -0700 Message-ID: <20260826191033.162320-3-fredric.cover.lkernel@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260826191033.162320-1-fredric.cover.lkernel@gmail.com> References: <20260826191033.162320-1-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 Currently, copy_ref_data() assumes that numrefs > 0, and unconditinally accesses refs[0]. If copy_ref_data() somehow is passed an empty list, this would cause major out-of-bounds write and read problems. Enforce numrefs > 0. Signed-off-by: Fredric Cover --- fs/smb/client/dfs_cache.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/smb/client/dfs_cache.c b/fs/smb/client/dfs_cache.c index b0388c460499..b51c8355d73d 100644 --- a/fs/smb/client/dfs_cache.c +++ b/fs/smb/client/dfs_cache.c @@ -389,6 +389,9 @@ static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs, struct cache_dfs_tgt *target; int i; + if (WARN_ON_ONCE(numrefs <= 0)) + return -EINVAL; + for (i = 0; i < numrefs; i++) { struct cache_dfs_tgt *t; -- 2.53.0