Messages in this thread Patch in this message | | | Date | Fri, 05 Aug 2011 17:02:20 -0700 | From | Greg KH <> | Subject | [50/55] proc: restrict access to /proc/PID/io |
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2.6.32-longterm review patch. If anyone has any objections, please let us know.
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From: Vasiliy Kulikov <segoon@openwall.com>
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>
--- fs/proc/base.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2454,6 +2454,9 @@ 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; @@ -2575,7 +2578,7 @@ 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 }; @@ -2910,7 +2913,7 @@ 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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