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Tue, 31 Mar 2026 23:04:16 -0700 (PDT) Received: from google.com ([2a00:79e0:2ebe:8:1dbf:b0e0:8ad0:5a2e]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2c3c6e9bd48sm11457498eec.20.2026.03.31.23.04.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 31 Mar 2026 23:04:15 -0700 (PDT) Date: Tue, 31 Mar 2026 23:04:13 -0700 From: Dmitry Torokhov To: Jiri Kosina Cc: Benjamin Tissoires , Peter Hutterer , Kees Cook , Alan Stern , Charles Keepax , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] HID: core: do not allow parsing 0-sized reports Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Commit d7db259bd6df ("HID: core: factor out hid_parse_collections()") reworked collection parsing code and inadvertently allowed returning "success" when parsing 0-sized reports where old code returned -EINVAL. Restore the original behavior by doing an explicit check. Note that the error message now differs from the generic "item fetching failed at offset %u/%u" that is now used only for non-empty descriptors. Fixes: d7db259bd6df ("HID: core: factor out hid_parse_collections()") Signed-off-by: Dmitry Torokhov --- drivers/hid/hid-core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index b40953e0f52e..be9d2b3356c3 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1272,6 +1272,11 @@ static int hid_parse_collections(struct hid_device *= device) device->collection[i].parent_idx =3D -1; =20 ret =3D -EINVAL; + if (start =3D=3D end) { + hid_err(device, "rejecting 0-sized report descriptor\n"); + goto out; + } + while ((next =3D fetch_item(start, end, &item)) !=3D NULL) { start =3D next; =20 --=20 2.53.0.1185.g05d4b7b318-goog --=20 Dmitry