linux/fs/proc
Jinliang Zheng c93a33f28f procfs: fix missing RCU protection when reading real_parent in do_task_stat()
[ Upstream commit 76149d5350 ]

When reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent
without proper RCU protection, which leads to:

  cpu 0                               cpu 1
  -----                               -----
  do_task_stat
    var = task->real_parent
                                      release_task
                                        call_rcu(delayed_put_task_struct)
    task_tgid_nr_ns(var)
      rcu_read_lock   <--- Too late to protect task->real_parent!
      task_pid_ptr    <--- UAF!
      rcu_read_unlock

This patch uses task_ppid_nr_ns() instead of task_tgid_nr_ns() to add
proper RCU protection for accessing task->real_parent.

Link: https://lkml.kernel.org/r/20260128083007.3173016-1-alexjlzheng@tencent.com
Fixes: 06fffb1267 ("do_task_stat: don't take rcu_read_lock()")
Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: ruippan <ruippan@tencent.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2026-03-04 07:19:37 -05:00
..
array.c procfs: fix missing RCU protection when reading real_parent in do_task_stat() 2026-03-04 07:19:37 -05:00
base.c fs/procfs: fix the comment above proc_pid_wchan() 2025-04-10 14:32:02 +02:00
bootconfig.c proc: bootconfig: Add null pointer check 2022-04-08 14:24:12 +02:00
cmdline.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
consoles.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 191 2019-05-30 11:29:21 -07:00
cpuinfo.c proc/cpuinfo: switch to ->read_iter 2020-11-06 10:05:18 -08:00
devices.c block: move block-related definitions out of fs.h 2020-06-24 09:16:02 -06:00
fd.c procfs: prevent unprivileged processes accessing fdinfo dir 2022-05-18 10:26:50 +02:00
fd.h fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
generic.c fs/proc: fix uaf in proc_readdir_de() 2025-12-07 06:09:29 +09:00
inode.c fix proc_sys_compare() handling of in-lookup dentries 2025-07-17 18:30:46 +02:00
internal.h proc: fix UAF in proc_get_inode() 2025-04-10 14:31:55 +02:00
interrupts.c proc: introduce proc_create_seq{,_data} 2018-05-16 07:23:35 +02:00
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
kcore.c fs/proc/kcore: use page_offline_(freeze|thaw) 2021-06-30 20:47:28 -07:00
kmsg.c proc: faster open/read/close with "permanent" files 2020-04-07 10:43:42 -07:00
loadavg.c sched: Make nr_running() return 32-bit value 2021-05-12 21:34:14 +02:00
Makefile proc: bootconfig: Add /proc/bootconfig to show boot config list 2020-01-13 13:19:39 -05:00
meminfo.c mm: memcontrol: convert NR_FILE_PMDMAPPED account to pages 2021-02-24 13:38:29 -08:00
namespaces.c Merge branch 'work.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-01-29 11:20:24 -08:00
nommu.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
page.c mm: Add PG_arch_2 page flag 2020-09-04 12:46:06 +01:00
proc_net.c proc: fix dentry/inode overinstantiating under /proc/${pid}/net 2022-06-09 10:23:10 +02:00
proc_sysctl.c fix proc_sys_compare() handling of in-lookup dentries 2025-07-17 18:30:46 +02:00
proc_tty.c tty: replace ->proc_fops with ->proc_show 2018-05-16 07:24:30 +02:00
root.c fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
self.c Revert "proc: don't allow async path resolution of /proc/self components" 2021-02-23 20:32:11 -07:00
softirqs.c proc/softirqs: replace seq_printf with seq_put_decimal_ull_width 2024-12-14 19:50:41 +01:00
stat.c fs/proc/uptime.c: Fix idle time reporting in /proc/uptime 2021-11-18 19:16:13 +01:00
task_mmu.c fs/proc/task_mmu: indicate PM_FILE for PMD-mapped file THP 2024-08-19 05:45:09 +02:00
task_nommu.c proc: nommu: /proc/<pid>/maps: release mmap read lock 2023-10-06 13:18:22 +02:00
thread_self.c Revert "proc: don't allow async path resolution of /proc/thread-self components" 2021-02-23 20:32:11 -07:00
uptime.c fs/proc/uptime.c: Fix idle time reporting in /proc/uptime 2021-11-18 19:16:13 +01:00
util.c fs/proc/util.c: include fs/proc/internal.h for name_to_int() 2019-01-04 13:13:45 -08:00
version.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
vmcore.c fs/proc: fix softlockup in __read_vmcore (part 2) 2025-01-23 17:16:02 +01:00