From: Ye Bin <yebin10@huawei.com> hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IBRR1N CVE: NA Reference: https://lore.kernel.org/linux-fsdevel/20250301034024.277290-1-yebin@huaweicl... -------------------------------- There's a issue as follows: BUG: unable to handle page fault for address: fffffbfff80a702b PGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:proc_get_inode+0x302/0x6e0 RSP: 0018:ffff88811c837998 EFLAGS: 00010a06 RAX: dffffc0000000000 RBX: ffffffffc0538140 RCX: 0000000000000007 RDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158 RBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20 R10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78f0 R13: ffff888100518048 R14: ffff8881299a6004 R15: 0000000000000001 FS: 00007f95b9686840(0000) GS:ffff8883af100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffbfff80a702b CR3: 0000000117dd2000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> proc_lookup_de+0x11f/0x2e0 __lookup_slow+0x188/0x350 walk_component+0x2ab/0x4f0 path_lookupat+0x120/0x660 filename_lookup+0x1ce/0x560 vfs_statx+0xac/0x150 __do_sys_newstat+0x96/0x110 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e Above issue may happen as follows: rmmod lookup sys_delete_module proc_lookup_de read_lock(&proc_subdir_lock); pde_get(de); read_unlock(&proc_subdir_lock); proc_get_inode(dir->i_sb, de); mod->exit() proc_remove remove_proc_subtree write_lock(&proc_subdir_lock); write_unlock(&proc_subdir_lock); proc_entry_rundown(de); free_module(mod); if (S_ISREG(inode->i_mode)) if (de->proc_ops->proc_read_iter) --> As module is already freed, will trigger UAF To solve above issue there's need to get 'in_use' before use proc_dir_entry in proc_get_inode(). Fixes: 9c7af565c58e ("centos 8.1: import linux-4.18.0-147.5.1.el8_1") Signed-off-by: Ye Bin <yebin10@huawei.com> Conflicts: fs/proc/inode.c [The pre-patch d919b33dafb3 ("proc: faster open/read/close with "permanent" files") is not imported.] Signed-off-by: Wang Zhaolong <wangzhaolong1@huawei.com> --- fs/proc/inode.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 31bf3bb8ddae..7d225a2b8b2a 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -460,10 +460,18 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) if (is_empty_pde(de)) { make_empty_dir_inode(inode); return inode; } + + if (!use_pde(de)) { + PROC_I(inode)->pde = NULL; + pde_put(de); + iput(inode); + return NULL; + } + if (de->mode) { inode->i_mode = de->mode; inode->i_uid = de->uid; inode->i_gid = de->gid; } @@ -484,10 +492,11 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) inode->i_fop = &proc_reg_file_ops; } else { inode->i_fop = de->proc_fops; } } + unuse_pde(de); } else pde_put(de); return inode; } -- 2.39.2