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authorMickaël Salaün <mic@linux.microsoft.com>2020-10-30 13:38:48 +0100
committerKees Cook <keescook@chromium.org>2020-11-17 12:53:22 -0800
commitcf23705244c947151179f929774fabf71e239eee (patch)
treeded22f89c5bdde0719aa404ecebf44ef6088b551 /kernel
parent09162bc32c880a791c6c0668ce0745cf7958f576 (diff)
ptrace: Set PF_SUPERPRIV when checking capability
Commit 69f594a38967 ("ptrace: do not audit capability check when outputing /proc/pid/stat") replaced the use of ns_capable() with has_ns_capability{,_noaudit}() which doesn't set PF_SUPERPRIV. Commit 6b3ad6649a4c ("ptrace: reintroduce usage of subjective credentials in ptrace_has_cap()") replaced has_ns_capability{,_noaudit}() with security_capable(), which doesn't set PF_SUPERPRIV neither. Since commit 98f368e9e263 ("kernel: Add noaudit variant of ns_capable()"), a new ns_capable_noaudit() helper is available. Let's use it! As a result, the signature of ptrace_has_cap() is restored to its original one. Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Eric Paris <eparis@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Tyler Hicks <tyhicks@linux.microsoft.com> Cc: stable@vger.kernel.org Fixes: 6b3ad6649a4c ("ptrace: reintroduce usage of subjective credentials in ptrace_has_cap()") Fixes: 69f594a38967 ("ptrace: do not audit capability check when outputing /proc/pid/stat") Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Reviewed-by: Jann Horn <jannh@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201030123849.770769-2-mic@digikod.net
Diffstat (limited to 'kernel')
-rw-r--r--kernel/ptrace.c16
1 files changed, 5 insertions, 11 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 43d6179508d6..79de1294f8eb 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -264,17 +264,11 @@ static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
return ret;
}
-static bool ptrace_has_cap(const struct cred *cred, struct user_namespace *ns,
- unsigned int mode)
+static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
{
- int ret;
-
if (mode & PTRACE_MODE_NOAUDIT)
- ret = security_capable(cred, ns, CAP_SYS_PTRACE, CAP_OPT_NOAUDIT);
- else
- ret = security_capable(cred, ns, CAP_SYS_PTRACE, CAP_OPT_NONE);
-
- return ret == 0;
+ return ns_capable_noaudit(ns, CAP_SYS_PTRACE);
+ return ns_capable(ns, CAP_SYS_PTRACE);
}
/* Returns 0 on success, -errno on denial. */
@@ -326,7 +320,7 @@ static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
gid_eq(caller_gid, tcred->sgid) &&
gid_eq(caller_gid, tcred->gid))
goto ok;
- if (ptrace_has_cap(cred, tcred->user_ns, mode))
+ if (ptrace_has_cap(tcred->user_ns, mode))
goto ok;
rcu_read_unlock();
return -EPERM;
@@ -345,7 +339,7 @@ ok:
mm = task->mm;
if (mm &&
((get_dumpable(mm) != SUID_DUMP_USER) &&
- !ptrace_has_cap(cred, mm->user_ns, mode)))
+ !ptrace_has_cap(mm->user_ns, mode)))
return -EPERM;
return security_ptrace_access_check(task, mode);