From 1d1221f375c94ef961ba8574ac4f85c8870ddd51 Mon Sep 17 00:00:00 2001 From: Vasiliy Kulikov Date: Fri, 24 Jun 2011 16:08:38 +0400 Subject: [PATCH] proc: restrict access to /proc/PID/io /proc/PID/io may be used for gathering private information. E.g. for openssh and vsftpd daemons wchars/rchars may be used to learn the precise password length. Restrict it to processes being able to ptrace the target process. ptrace_may_access() is needed to prevent keeping open file descriptor of "io" file, executing setuid binary and gathering io information of the setuid'ed process. Signed-off-by: Vasiliy Kulikov Signed-off-by: Linus Torvalds --- fs/proc/base.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 8a84210ca080..fc5bc2767692 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2708,6 +2708,9 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole) struct task_io_accounting acct = task->ioac; unsigned long flags; + if (!ptrace_may_access(task, PTRACE_MODE_READ)) + return -EACCES; + if (whole && lock_task_sighand(task, &flags)) { struct task_struct *t = task; @@ -2839,7 +2842,7 @@ static const struct pid_entry tgid_base_stuff[] = { REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations), #endif #ifdef CONFIG_TASK_IO_ACCOUNTING - INF("io", S_IRUGO, proc_tgid_io_accounting), + INF("io", S_IRUSR, proc_tgid_io_accounting), #endif #ifdef CONFIG_HARDWALL INF("hardwall", S_IRUGO, proc_pid_hardwall), @@ -3181,7 +3184,7 @@ static const struct pid_entry tid_base_stuff[] = { REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), #endif #ifdef CONFIG_TASK_IO_ACCOUNTING - INF("io", S_IRUGO, proc_tid_io_accounting), + INF("io", S_IRUSR, proc_tid_io_accounting), #endif #ifdef CONFIG_HARDWALL INF("hardwall", S_IRUGO, proc_pid_hardwall), -- 2.20.1