2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------
From: Vasiliy Kulikov <seg...@openwall.com>
[ upstream commit 1d1221f375c94ef961ba8574ac4f85c8870ddd51 ]
/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.
Said to be CVE-2011-2495
Signed-off-by: Vasiliy Kulikov <seg...@openwall.com>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Andi Kleen <a...@linux.intel.com>
Index: linux-2.6.35.y/fs/proc/base.c
===================================================================
--- linux-2.6.35.y.orig/fs/proc/base.c
+++ linux-2.6.35.y/fs/proc/base.c
@@ -2514,6 +2514,9 @@ static int do_io_accounting(struct task_
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;
@@ -2636,7 +2639,7 @@ static const struct pid_entry tgid_base_
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
};
@@ -2972,7 +2975,7 @@ static const struct pid_entry tid_base_s
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
};
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