From: Xiaotian Feng Date: Fri, 13 Jan 2012 01:17:08 +0000 (-0800) Subject: proc: fix null pointer deref in proc_pid_permission() X-Git-Tag: Ubuntu-5.2.0-15.16~18921^2~95 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=a2ef990ab5a6705a356d146dd773a3b359787497;p=mirror_ubuntu-eoan-kernel.git proc: fix null pointer deref in proc_pid_permission() get_proc_task() can fail to search the task and return NULL, put_task_struct() will then bomb the kernel with following oops: BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 IP: [] proc_pid_permission+0x64/0xe0 PGD 112075067 PUD 112814067 PMD 0 Oops: 0002 [#1] PREEMPT SMP This is a regression introduced by commit 0499680a ("procfs: add hidepid= and gid= mount options"). The kernel should return -ESRCH if get_proc_task() failed. Signed-off-by: Xiaotian Feng Cc: Al Viro Cc: Vasiliy Kulikov Cc: Stephen Wilson Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/proc/base.c b/fs/proc/base.c index 8173dfd89cb2..5485a5388ecb 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -654,6 +654,8 @@ static int proc_pid_permission(struct inode *inode, int mask) bool has_perms; task = get_proc_task(inode); + if (!task) + return -ESRCH; has_perms = has_pid_permissions(pid, task, 1); put_task_struct(task);