Octobre 2026

Linux

In the Linux kernel, the following vulnerability has been resolved: namespace: unhash a dentry before detaching the mounts on it unlink(), rmdir() and rename() remove the entry from the filesystem, call detach_mounts() on the entry with the inode locked and then call d_delete() once the inode is unlocked. The thing is that between detach_mounts() and d_delete() the dentry is still hashed and positive. But after detach_mounts() nothing covers the dentry anymore. A lookup that finds this dentry in the dcache can uncover what the mounts hid. That's a problem when unlinking files or directories that are mountpoints in other mount namespaces. Everybody who had the underlying entry covered can race the detach_mount() call until d_delete() has run. The race window isn't all that small. It encompasses namespace_unlock() with a full synchronize_rcu_expedited() grace period and the inode_unlock() of the entry. In my experiments three walkers that kept trying read an overmounted file in 11938 of the 16140 unlinks that removed its mountpoint from a bind mount of the filesystem within a minute. Fun fact, d_invalidate() has the same ordering problem but gets it right. It unhashes the dentry first and detaches the mounts afterwards. Let's do the same in __detach_mounts(): - A lookup that hasn't found the dentry yet misses it in the dcache and waits for the directory lock that the caller holds until the name is gone for good. - A lockless lookup that found it already fails the mount_lock check while the dentry still counts as a mountpoint and the d_seq check once it doesn't, and retries. This fixes the lockless path. We still need to fix the reference count lookup in a follow-up patch. So d_drop() the dentry. The dentry stays positive and held but can't be found anymore. Then proceed with the detach and unlink. Reproducer: The reads were counted with the program below, three walkers for 60 s in a VM with 4 CPUs. The race window is stretched with the debug patch pasted here. fs.detach_race_walk_us sleeps in lookup_fast() once it found a mountpoint dentry and before its mounts are crossed. fs.detach_race_unlink_us sleeps in vfs_unlink() between detach_mounts() and d_delete(). // SPDX-License-Identifier: GPL-2.0 /* * unlink_covered: unlink a file that is a mountpoint in a detached copy of * its mount, against lookups that open it through that copy. * * A is a tmpfs with the file f1 (content SECRET_F) and the plain file * MARK_A. A' is an open_tree(OPEN_TREE_CLONE) copy of A with MARK_A bound * on A'/f1, held through an O_PATH fd on its root once the tree fd is * closed. Walkers open f1 through that fd while the driver unlinks A/f1, * where nothing is mounted on it. A walker may read MARK_A or get ENOENT. * A read of SECRET_F is a hit: the name was found after its mount was * gone. The lockless walks use openat2(RESOLVE_CACHED). * * usage: unlink_covered [-t seconds] [-w walkers] */ #ifndef _GNU_SOURCE #define _GNU_SOURCE #endif #include <errno.h> #include <fcntl.h> #include <pthread.h> #include <stdatomic.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/mount.h> #include <sys/stat.h> #include <sys/syscall.h> #include <linux/openat2.h> #ifndef __NR_open_tree #define __NR_open_tree 428 #endif #ifndef __NR_move_mount #define __NR_move_mount 429 #endif #ifndef __NR_openat2 #define __NR_openat2 437 #endif #ifndef OPEN_TREE_CLONE #define OPEN_TREE_CLONE 1 #endif #ifndef OPEN_TREE_CLOEXEC #define OPEN_TREE_CLOEXEC O_CLOEXEC #endif #ifndef MOVE_MOUNT_F_EMPTY_PATH #define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 #endif #define WORK "/tmp/uc" #define ADIR WORK "/A" static int duration = 60, nwalkers = 3; static atomic_int stop, writer_waiting; static pthread_rwlock_t cur_lock = PTHREAD_RWLOCK_INITIALIZER; static int cur_fd = -1; /* the root of A', -1 wh ---truncated---

Linux

In the Linux kernel, the following vulnerability has been resolved: namei: don't reveal overmounted entries in refwalk In rcuwalk the dentry is validated before it is accepted. step_into() step_into() rechecks d_seq and __follow_mount_rcu() rechecks mount_lock. An entry that gets unlinked in between causes the lookup to retry and miss. A refwalk doesn't do this. lookup_fast() takes a reference on the hashed dentry and simply accepts it. So an unlink that happens after the reference was taken isn't seen by refwalk. That's fine for a simple file. We just happened to open it before it was unlinked, no problem. For a mountpoint and specifically a locked mountpoint it very much isn't. The unlink detaches all mounts and then removes the name. Any refwalk that hasn't traversed the mounts yet simply reveals the underlying entry. It's a very narrow window but it can be hit: reads of a covered file in 60 s, 3 walkers, ~15000 unlinks no widening 27 that step + 200 us 3741 See the appended patch for a more reliable reproducer. So check the entry after step_into(). unlink(), rmdir() and rename() mark the dentry with dont_mount() before they detach the mounts and remove the dentry. So a dentry that is marked with DCACHE_CANT_MOUNT and is unhashed by the time its mounts were looked at is a name that was unlinked under the refwalk. DCACHE_CANT_MOUNT is read after the mounts were looked up and it is set before they are detached by detach_mounts(). A refwalk that missed the mounts will see DCACHE_CANT_MOUNT. Plain d_unlinked() is fine. A rename takes the dentry off its hash chain but ___d_drop() leaves d_hash.pprev set. So only __d_drop() and a rename over the dentry unhash it. The only move that flips IS_ROOT splices in a disconnected alias. That doesn't have DCACHE_CANT_MOUNT set. Add the to step_into_slowpath(). ".." and LOOKUP_DOWN may legitimately land on an unhashed directory. A refwalk that crossed onto a mount has path.mnt different from nd->path.mnt. A dentry that a filesystem dropped on its own (d_invalidate(), d_drop()) doesn't have the flag set and is treated as before. // SPDX-License-Identifier: GPL-2.0 /* * unlink_covered: unlink a file that is a mountpoint in a detached copy of * its mount, against walkers that open it through that copy. * * A is a tmpfs with the file f1 (content SECRET_F) and the plain file * MARK_A. A' is an open_tree(OPEN_TREE_CLONE) copy of A with MARK_A bound * on A'/f1, held through an O_PATH fd on its root once the tree fd is * closed. Walkers open f1 through that fd while the driver unlinks A/f1, * where nothing is mounted on it. A walker may read MARK_A or get ENOENT. * A read of SECRET_F is a hit: the name was found after its mount was * gone. The lockless walks use openat2(RESOLVE_CACHED). * * usage: unlink_covered [-t seconds] [-w walkers] */ #ifndef _GNU_SOURCE #define _GNU_SOURCE #endif #include <errno.h> #include <fcntl.h> #include <pthread.h> #include <stdatomic.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/mount.h> #include <sys/stat.h> #include <sys/syscall.h> #include <linux/openat2.h> #ifndef __NR_open_tree #define __NR_open_tree 428 #endif #ifndef __NR_move_mount #define __NR_move_mount 429 #endif #ifndef __NR_openat2 #define __NR_openat2 437 #endif #ifndef OPEN_TREE_CLONE #define OPEN_TREE_CLONE 1 #endif #ifndef OPEN_TREE_CLOEXEC #define OPEN_TREE_CLOEXEC O_CLOEXEC #endif #ifndef MOVE_MOUNT_F_EMPTY_PATH #define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 #endif #define WORK "/tmp/uc" #define ADIR WORK "/A" static int duration = 60, nwalkers = 3; static atomic_int stop, writer_waiting; static pthread_rwlock_t cur_lock = PTHREAD_RWLOCK_INITIALIZER; static int cur_fd = -1; /* the root of A', -1 while there is none */ static atomic_long n_unlink, n_walk, n_mark, n_enoent, n_othe ---truncated---

Kusalkasilva Learning-Management-System

A vulnerability was determined in Kusalkasilva Learning-Management-System up to ffeb873f8803f1e9664384ff75000c7da45466d2. The impacted element is an unknown function of the file student_signup.php of the component Student Registration Endpoint. This manipulation causes sql injection. The attack may be initiated remotely. The exploit has been publicly disclosed and may be utilized. This product uses a rolling release model to deliver continuous updates. As a result, specific version information for affected or updated releases is not available. The project was informed of the problem early through an issue report but has not responded yet.

Linux

In the Linux kernel, the following vulnerability has been resolved: mips: select CONFIG_WEAK_REORDERING_BEYOND_LLSC from CONFIG_EYEQ On I6500 CPU cores, lld and scd give no ordering guarantees (same as all other instructions). To respect the assumption that arch_cmpxchg() is fully ordered, we must inject sync instructions above and below our lld/scd loops using the already in place WEAK_REORDERING_BEYOND_LLSC infrastructure. Otherwise, bad things can happen: [ 34.054496] CPU 3 Unable to handle kernel paging request at virtual address 0000000000000000, epc == a80000080838e01c, ra == a80000080838dfc4 [ 34.054559] Oops[#1]: [ 34.069561] CPU: 3 UID: 0 PID: 170 Comm: pipe_race Not tainted 7.2.0-rc6-01553-gb73c35220968-dirty #103 VOLUNTARY [ 34.079932] Hardware name: Mobile EyeQ5 MP5 Evaluation board [ 34.085592] $ 0 : 0000000000000000 0000000000000001 0000000000000000 0000000000000000 [ 34.093616] $ 4 : a800000808ee2618 000000000b7a879d 0000000000001000 0000000000000000 [ 34.101638] $ 8 : 0000000000e3f2c9 0000000000000000 a800000808a2a9f8 0000000000000000 [ 34.109660] $12 : a8000008139ffcd8 ffffffff84080018 a80000080837fae0 7878787878787878 [ 34.117682] $16 : a800000807e82940 0000000000001000 0000000000000000 0000000000000000 [ 34.125704] $20 : a800000802920e00 a8000008139ffdf8 a800000802649400 0000000000e3f2c9 [ 34.133726] $24 : 0000000000000006 00000001200406e0 [ 34.141783] $28 : a8000008139fc000 a8000008139ffd10 0000000000e3f2c8 a80000080838dfc4 [ 34.149837] epc : a80000080838e01c anon_pipe_read+0xd4/0x428 [ 34.155697] ra : a80000080838dfc4 anon_pipe_read+0x7c/0x428 [ 34.161549] Status: 140000e3 KX SX UX KERNEL EXL IE [ 34.166551] Cause : 40800408 (ExcCode 02) [ 34.170574] BadVA : 0000000000000000 [ 34.174161] PrId : 0001b028 (MIPS I6500) [ 34.178183] Process pipe_race (pid: 170, threadinfo=000000005ca35720, task=00000000e1013890, tls=000000014ebbb780) [ 34.188568] Stack : a800000802649400 0000000000000000 0000000000000000 a8000008139ffdd0 [ 34.196623] 0000000000000fba a800000808ee0000 0000000000000001 a8000008130c3e80 [ 34.204676] a8000008080d1280 a8000008139ffd58 a8000008139ffd58 1dbd2b22ea1dd500 [ 34.212729] a800000802649400 a800000808ee0000 ffffffffffffffea 0000000000000001 [ 34.220783] 0000000000001000 0000000000000000 00000001200ae518 ffffffffffffffff [ 34.228836] 000000fffbe0e530 a80000080837edf4 000000fffbe0e530 0000000000000000 [ 34.236890] 0000000000000000 0000000000000000 000000014ebb55a0 0000000000001000 [ 34.244943] 0000000000000001 a800000802649400 0000000000000000 0000000000000000 [ 34.252996] 0000000000000000 0000400400000000 0000000000000000 1dbd2b22ea1dd500 [ 34.261049] 00000000140000e3 a800000802649400 a800000802649400 a800000808ee0000 [ 34.269103] ... [ 34.271568] Call Trace: [ 34.274026] [<a80000080838e01c>] anon_pipe_read+0xd4/0x428 [ 34.279533] [<a80000080837edf4>] vfs_read+0x25c/0x318 [ 34.284607] [<a80000080837faac>] ksys_read+0x104/0x138 [ 34.289763] [<a80000080802b9cc>] syscall_common+0x44/0x68 [ 34.295187] [ 34.296689] Code: f84000cf 02209825 de020010 <dc420000> d8400004 02002825 0040f809 02802025 f84000c3 [ 34.306504] [ 34.308099] ---[ end trace 0000000000000000 ]--- My initial reproducer was the xdp-tools test suite. A standalone reproducer would be an lld/scd loop that, when the read is reordered by the CPU, triggers a fault. We can achieve this from userspace by stressing an anonymous pipe, which uses a mutex. Program used: // SPDX-License-Identifier: GPL-2.0 // pipe_race.c - reproducer for MIPS LL/SC reordering vs fs/pipe.c // // Two userspace processes on an anonymous pipe: // parent = writer: tight write() loop // child = reader: tight read() loop #define _GNU_SOURCE #include <assert.h> #include <errno.h> #include <sched.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include ---truncated---

girishsaraf Online-Appointment-Booking-System

A security flaw has been discovered in girishsaraf Online-Appointment-Booking-System up to f427b4757128ca253d33d0cc4e87bbb9c999a4d5. Impacted is an unknown function of the file signup.php of the component Registration Handler. The manipulation of the argument fname results in sql injection. The attack can be executed remotely. The exploit has been released to the public and may be used for attacks. This product implements a rolling release for ongoing delivery, which means version information for affected or updated releases is unavailable. The project was informed of the problem early through an issue report but has not responded yet.

kishor-23 food-waste-management-system

A flaw has been found in kishor-23 food-waste-management-system 411989e3ecb82895e53dca7865f72145f03d7d93/b3a70b2c492dc9904de5be1ad9389bd79b87f82c. The impacted element is an unknown function of the file delivery/deliverysignup.php of the component Registration Page. This manipulation of the argument username/email/location causes sql injection. The attack can be initiated remotely. The exploit has been published and may be used. Continious delivery with rolling releases is used by this product. Therefore, no version details of affected nor updated releases are available. The project was informed of the problem early through an issue report but has not responded yet.

kishor-23 food-waste-management-system

A vulnerability was detected in kishor-23 food-waste-management-system 411989e3ecb82895e53dca7865f72145f03d7d93/b3a70b2c492dc9904de5be1ad9389bd79b87f82c. The affected element is an unknown function of the file admin/signup.php of the component Admin Registration. The manipulation of the argument email/username/location results in sql injection. It is possible to launch the attack remotely. The exploit is now public and may be used. This product takes the approach of rolling releases to provide continious delivery. Therefore, version details for affected and updated releases are not available. The project was informed of the problem early through an issue report but has not responded yet.

kishor-23 food-waste-management-system

A weakness has been identified in kishor-23 food-waste-management-system 411989e3ecb82895e53dca7865f72145f03d7d93/b3a70b2c492dc9904de5be1ad9389bd79b87f82c. This issue affects some unknown processing of the file signup.php of the component User Registration Endpoint. Executing a manipulation of the argument email/name/gender can lead to sql injection. The attack may be performed from remote. The exploit has been made available to the public and could be used for attacks. This product utilizes a rolling release system for continuous delivery, and as such, version information for affected or updated releases is not disclosed. The project was informed of the problem early through an issue report but has not responded yet.

kishor-23 food-waste-management-system

A weakness has been identified in kishor-23 food-waste-management-system 411989e3ecb82895e53dca7865f72145f03d7d93/b3a70b2c492dc9904de5be1ad9389bd79b87f82c. Affected is an unknown function of the file admin/signup.php of the component Admin Signup. This manipulation of the argument sign causes missing authentication. The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks. Continious delivery with rolling releases is used by this product. Therefore, no version details of affected nor updated releases are available. The project was informed of the problem early through an issue report but has not responded yet.