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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-28 11:20:52 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-28 11:20:52 -0700 |
| commit | 26e811cdb9f10357ee4f5885aab972111486b044 (patch) | |
| tree | 0a26b5dc005f06a64c6bc8ec301576f1f4cbb00a /kernel | |
| parent | 9cd6681cb1169e815c41af0265165dd1b872f228 (diff) | |
| parent | 66a733ea6b611aecf0119514d2dddab5f9d6c01e (diff) | |
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()
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/seccomp.c | 23 |
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: |