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authorVasiliy Kulikov <segoon@openwall.com>2011-06-24 16:08:38 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-06-28 09:39:11 -0700
commit1d1221f375c94ef961ba8574ac4f85c8870ddd51 (patch)
tree1e05f1c33bef03a88745c55ac9891b8423ae1795 /fs/proc
parentb0af8dfdd67699e25083478c63eedef2e72ebd85 (diff)
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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 <segoon@openwall.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/base.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 8a84210..fc5bc27 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),