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Wysocki" Cc: Chun-Yi Lee , David Howells , Lorenzo Stoakes , Andy Shevchenko , Thomas Gleixner , Matthew Garrett , Greg Kroah-Hartman , Danilo Krummrich , driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260615104750.1000-1-jlee@suse.com> From: Disha Goel In-Reply-To: <20260615104750.1000-1-jlee@suse.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Info: AW1haW4tMjYwNjE5MDEwMCBTYWx0ZWRfX2Ltpt4T61Rw7 5+fFZ9BUEnNSoC3fWjiVWa2AECZ4hFnBEs4f6g+5WKgM7/VFnHlgFY3Jos6J8esDws6Qw5eMqLr MZ6uKWRbZ7ma3SW/32qdbq2rGMlIdoM= X-Proofpoint-GUID: C64KMeHamkSssRkxLlB7VHdcLQgDKbDB X-Authority-Analysis: v=2.4 cv=bMgm5v+Z c=1 sm=1 tr=0 ts=6a352406 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=iox4zFpeAAAA:8 a=20KFwNOVAAAA:8 a=VwQbUJbxAAAA:8 a=pGLkceISAAAA:8 a=9Rt4o3Z7AAAA:8 a=ag1SF4gXAAAA:8 a=VnNF1IyMAAAA:8 a=3kR2PXdCzuXVfo5DH_oA:9 a=QEXdDO2ut3YA:10 a=WzC6qhA0u3u7Ye7llzcV:22 a=jE01AiZSAJ7eki2zvjzZ:22 a=Yupwre4RP9_Eg_Bd0iYG:22 X-Proofpoint-ORIG-GUID: FtCyyGXeGTb0hE4YmkpKhNq5SCHztS6I X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjE5MDEwMCBTYWx0ZWRfX626r8NBrSrWZ awtwFxooPbmiz0pOj17ssaK50MzaW47nnvqos9uGDRVwehLgKQ5mD78yJWKIuV97YQR6uf7veog V38nXxWalSN+ZQ6c/Oia8UWwY4Dd8BK6eEvLYdRf4eI4TMKSWGV/0KKOlXVQRAE9bsCGlA5jy6X bnVTcU20VVWC1oDbUyCnsEeh00f1iphA8ZcCGRqbnFBUZFhKMI3doQuN2JuiBrA4001HMJzTbeL bxWgSkOFvdFC2/S+T63eqdk0I56hfManWQKs8/S0M1inB+FbJbWuSz7g943h7zVwwQ1kZrvy1Ay LZTOw3YBW+6TdH1yWViI73jGdTFGOk1nToVXvAASg89AjI3j9puKTkDpp+zKzbjwCtcBllGYV7i 7i9nWhCrp8iTGRj1zvtaZAeDI+De3/HrXSmJXYwjjPEHj8UZN8DHdjXdf1bOyOZKLzadqRDFDjK 7MCaWCWzoL3HyNwWcTQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-19_02,2026-06-18_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 impostorscore=0 malwarescore=0 adultscore=0 spamscore=0 bulkscore=0 priorityscore=1501 phishscore=0 clxscore=1011 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606190100 On 15/06/26 4:17 pm, Chun-Yi Lee wrote: > From: Chun-Yi Lee > > Commit 651fdda8406d ("relay: update relay to use mmap_prepare") > changed the `mmap` file operation to `mmap_prepare` for relayfs, but > the lockdown check in debugfs was not updated accordingly. > > This prevents debugfs from being locked down when the kernel is in > integrity mode if a file uses `mmap_prepare` but not `mmap`. > > Since the conversion to `mmap_prepare` across the kernel is not yet > complete, update the lockdown check to look for both `mmap` and > `mmap_prepare` to ensure comprehensive coverage. > > Fixes: 651fdda8406d ("relay: update relay to use mmap_prepare") > Signed-off-by: Chun-Yi Lee > Cc: David Howells > Cc: Lorenzo Stoakes > Cc: Andy Shevchenko > Cc: Thomas Gleixner > Cc: Rafael J. Wysocki > Cc: Matthew Garrett > Cc: Greg Kroah-Hartman > Cc: Danilo Krummrich > Cc: driver-core@lists.linux.dev > Cc: linux-kernel@vger.kernel.org > Cc: stable@vger.kernel.org > --- Hi, I tested this patch on ppc64le with lockdown enabled. It correctly fixes the security issue where debugfs files using mmap_prepare were not being restricted. Test: blktrace/001 from blktests (uses relayfs via debugfs) - Before patch: blktrace bypassed lockdown and accessed debugfs - After patch: blktrace properly blocked from accessing debugfs Environment: Kernel: 7.1.0-rc7 Lockdown: integrity mode Feel free to add: Tested-by: Disha Goel > v2: > - Add explicit From tag to match Signed-off-by. > - Fix Lorenzo's email address. > - Add Cc stable for backporting. > - Check both mmap and mmap_prepare as suggested by Lorenzo. > > fs/debugfs/file.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c > index edd6aafbfbaa..08de6652a4f3 100644 > --- a/fs/debugfs/file.c > +++ b/fs/debugfs/file.c > @@ -273,7 +273,8 @@ static int debugfs_locked_down(struct inode *inode, > (!real_fops || > (!real_fops->unlocked_ioctl && > !real_fops->compat_ioctl && > - !real_fops->mmap))) > + !real_fops->mmap && > + !real_fops->mmap_prepare))) > return 0; > > if (security_locked_down(LOCKDOWN_DEBUGFS)) -- Regards, Disha