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authorLinus Torvalds <torvalds@linux-foundation.org>2017-09-28 11:20:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-28 11:20:52 -0700
commit26e811cdb9f10357ee4f5885aab972111486b044 (patch)
tree0a26b5dc005f06a64c6bc8ec301576f1f4cbb00a
parent9cd6681cb1169e815c41af0265165dd1b872f228 (diff)
parent66a733ea6b611aecf0119514d2dddab5f9d6c01e (diff)
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Merge tag 'seccomp-v4.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull seccomp fix from Kees Cook: "Fix refcounting bug in CRIU interface, noticed by Chris Salls (Oleg & Tycho)" * tag 'seccomp-v4.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: seccomp: fix the usage of get/put_seccomp_filter() in seccomp_get_filter()
-rw-r--r--kernel/seccomp.c23
1 files changed, 16 insertions, 7 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index c24579dfa7a1..bb3a38005b9c 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -473,14 +473,19 @@ static long seccomp_attach_filter(unsigned int flags,
return 0;
}
+void __get_seccomp_filter(struct seccomp_filter *filter)
+{
+ /* Reference count is bounded by the number of total processes. */
+ refcount_inc(&filter->usage);
+}
+
/* get_seccomp_filter - increments the reference count of the filter on @tsk */
void get_seccomp_filter(struct task_struct *tsk)
{
struct seccomp_filter *orig = tsk->seccomp.filter;
if (!orig)
return;
- /* Reference count is bounded by the number of total processes. */
- refcount_inc(&orig->usage);
+ __get_seccomp_filter(orig);
}
static inline void seccomp_filter_free(struct seccomp_filter *filter)
@@ -491,10 +496,8 @@ static inline void seccomp_filter_free(struct seccomp_filter *filter)
}
}
-/* put_seccomp_filter - decrements the ref count of tsk->seccomp.filter */
-void put_seccomp_filter(struct task_struct *tsk)
+static void __put_seccomp_filter(struct seccomp_filter *orig)
{
- struct seccomp_filter *orig = tsk->seccomp.filter;
/* Clean up single-reference branches iteratively. */
while (orig && refcount_dec_and_test(&orig->usage)) {
struct seccomp_filter *freeme = orig;
@@ -503,6 +506,12 @@ void put_seccomp_filter(struct task_struct *tsk)
}
}
+/* put_seccomp_filter - decrements the ref count of tsk->seccomp.filter */
+void put_seccomp_filter(struct task_struct *tsk)
+{
+ __put_seccomp_filter(tsk->seccomp.filter);
+}
+
static void seccomp_init_siginfo(siginfo_t *info, int syscall, int reason)
{
memset(info, 0, sizeof(*info));
@@ -1025,13 +1034,13 @@ long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
if (!data)
goto out;
- get_seccomp_filter(task);
+ __get_seccomp_filter(filter);
spin_unlock_irq(&task->sighand->siglock);
if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog)))
ret = -EFAULT;
- put_seccomp_filter(task);
+ __put_seccomp_filter(filter);
return ret;
out: