diff options
author | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2020-05-21 00:54:36 +0200 |
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committer | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2020-05-21 00:54:36 +0200 |
commit | 135d39dcedcedd1f44ea0bba52f15ac5922c114f (patch) | |
tree | 12379fc8ef7489eaca1c7245f8bd6af74c619a8f /kernel/ptrace.c | |
parent | 187764bd111b27783b6d68ffb3b3dbb3a9bafd38 (diff) | |
parent | 1279cd128bba968ebe0a2df7f7ae38bae90250ef (diff) |
Merge remote-tracking branch 'remotes/fslc/4.9-2.3.x-imx' into toradex_4.9-2.3.x-imx-next
Conflicts:
sound/soc/codecs/sgtl5000.c
sound/soc/fsl/imx-sgtl5000.c
Diffstat (limited to 'kernel/ptrace.c')
-rw-r--r-- | kernel/ptrace.c | 34 |
1 files changed, 29 insertions, 5 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index f39a7be98fc1..ea3370e205fb 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -74,9 +74,7 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent, */ static void ptrace_link(struct task_struct *child, struct task_struct *new_parent) { - rcu_read_lock(); - __ptrace_link(child, new_parent, __task_cred(new_parent)); - rcu_read_unlock(); + __ptrace_link(child, new_parent, current_cred()); } /** @@ -258,6 +256,9 @@ static int ptrace_check_attach(struct task_struct *child, bool ignore_state) static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode) { + if (mode & PTRACE_MODE_SCHED) + return false; + if (mode & PTRACE_MODE_NOAUDIT) return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE); else @@ -319,15 +320,32 @@ static int __ptrace_may_access(struct task_struct *task, unsigned int mode) return -EPERM; ok: rcu_read_unlock(); + /* + * If a task drops privileges and becomes nondumpable (through a syscall + * like setresuid()) while we are trying to access it, we must ensure + * that the dumpability is read after the credentials; otherwise, + * we may be able to attach to a task that we shouldn't be able to + * attach to (as if the task had dropped privileges without becoming + * nondumpable). + * Pairs with a write barrier in commit_creds(). + */ + smp_rmb(); mm = task->mm; if (mm && ((get_dumpable(mm) != SUID_DUMP_USER) && !ptrace_has_cap(mm->user_ns, mode))) return -EPERM; + if (mode & PTRACE_MODE_SCHED) + return 0; return security_ptrace_access_check(task, mode); } +bool ptrace_may_access_sched(struct task_struct *task, unsigned int mode) +{ + return __ptrace_may_access(task, mode | PTRACE_MODE_SCHED); +} + bool ptrace_may_access(struct task_struct *task, unsigned int mode) { int err; @@ -700,6 +718,10 @@ static int ptrace_peek_siginfo(struct task_struct *child, if (arg.nr < 0) return -EINVAL; + /* Ensure arg.off fits in an unsigned long */ + if (arg.off > ULONG_MAX) + return 0; + if (arg.flags & PTRACE_PEEKSIGINFO_SHARED) pending = &child->signal->shared_pending; else @@ -707,18 +729,20 @@ static int ptrace_peek_siginfo(struct task_struct *child, for (i = 0; i < arg.nr; ) { siginfo_t info; - s32 off = arg.off + i; + unsigned long off = arg.off + i; + bool found = false; spin_lock_irq(&child->sighand->siglock); list_for_each_entry(q, &pending->list, list) { if (!off--) { + found = true; copy_siginfo(&info, &q->info); break; } } spin_unlock_irq(&child->sighand->siglock); - if (off >= 0) /* beyond the end of the list */ + if (!found) /* beyond the end of the list */ break; #ifdef CONFIG_COMPAT |