| From 252bfabc61078363ed1171b32b316eb5dac88212 Mon Sep 17 00:00:00 2001 |
| From: Vasiliy Kulikov <segoon@openwall.com> |
| Date: Fri, 24 Jun 2011 16:08:38 +0400 |
| Subject: [PATCH] proc: restrict access to /proc/PID/io |
| |
| commit 1d1221f375c94ef961ba8574ac4f85c8870ddd51 upstream. |
| |
| /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 <segoon@openwall.com> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| --- |
| 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 268f00d..08741b0 100644 |
| --- a/fs/proc/base.c |
| +++ b/fs/proc/base.c |
| @@ -2518,6 +2518,9 @@ 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; |
| |
| @@ -2640,7 +2643,7 @@ 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 |
| }; |
| |
| @@ -2976,7 +2979,7 @@ 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 |
| }; |
| |
| -- |
| 1.7.9.6 |
| |