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authorVasiliy Kulikov <segoon@openwall.com>2011-06-24 16:08:38 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-08 10:23:19 -0700
commitfc10e555b21481e5f9ccbf9b4dc804140e556a04 (patch)
parent2beffeba8046011cf87062b842327328fb22cda7 (diff)
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: Greg Kroah-Hartman <gregkh@suse.de>
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3d09a1066b10..7b5819cac397 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2454,6 +2454,9 @@ 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;
@@ -2575,7 +2578,7 @@ static const struct pid_entry tgid_base_stuff[] = {
REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
- INF("io", S_IRUGO, proc_tgid_io_accounting),
+ INF("io", S_IRUSR, proc_tgid_io_accounting),
@@ -2910,7 +2913,7 @@ static const struct pid_entry tid_base_stuff[] = {
REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
- INF("io", S_IRUGO, proc_tid_io_accounting),
+ INF("io", S_IRUSR, proc_tid_io_accounting),