* [PATCH v3 1/2] seccomp: hoist out filter resolving logic
@ 2017-10-11 15:39 Tycho Andersen
2017-10-11 15:39 ` [PATCH v3 2/2] ptrace, seccomp: add support for retrieving seccomp metadata Tycho Andersen
2017-11-28 23:42 ` [PATCH v3 1/2] seccomp: hoist out filter resolving logic Kees Cook
0 siblings, 2 replies; 4+ messages in thread
From: Tycho Andersen @ 2017-10-11 15:39 UTC (permalink / raw)
To: Kees Cook; +Cc: linux-kernel, Tycho Andersen, Andy Lutomirski, Oleg Nesterov
Hoist out the nth filter resolving logic that ptrace uses into a new
function. We'll use this in the next patch to implement the new
PTRACE_SECCOMP_GET_FILTER_FLAGS command.
v3: * significantly revamp get_nth_filter logic (Oleg)
* rebase on 4.14-rc4, using the new __{get,put}_seccomp_filter
primitives
Signed-off-by: Tycho Andersen <tycho@docker.com>
CC: Kees Cook <keescook@chromium.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Oleg Nesterov <oleg@redhat.com>
---
kernel/seccomp.c | 77 +++++++++++++++++++++++++++++++++-----------------------
1 file changed, 45 insertions(+), 32 deletions(-)
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index bb3a38005b9c..2e1568261ac4 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -977,49 +977,68 @@ long prctl_set_seccomp(unsigned long seccomp_mode, char __user *filter)
}
#if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)
-long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
- void __user *data)
+static struct seccomp_filter *get_nth_filter(struct task_struct *task,
+ unsigned long filter_off)
{
- struct seccomp_filter *filter;
- struct sock_fprog_kern *fprog;
- long ret;
- unsigned long count = 0;
-
- if (!capable(CAP_SYS_ADMIN) ||
- current->seccomp.mode != SECCOMP_MODE_DISABLED) {
- return -EACCES;
- }
+ struct seccomp_filter *orig, *filter;
+ unsigned long count;
+ /*
+ * Note: this is only correct because the caller should be the (ptrace)
+ * tracer of the task, otherwise lock_task_sighand is needed.
+ */
spin_lock_irq(&task->sighand->siglock);
+
if (task->seccomp.mode != SECCOMP_MODE_FILTER) {
- ret = -EINVAL;
- goto out;
+ spin_unlock_irq(&task->sighand->siglock);
+ return ERR_PTR(-EINVAL);
}
- filter = task->seccomp.filter;
- while (filter) {
- filter = filter->prev;
+ orig = task->seccomp.filter;
+ __get_seccomp_filter(orig);
+ spin_unlock_irq(&task->sighand->siglock);
+
+ count = 0;
+ for (filter = orig; filter; filter = filter->prev)
count++;
- }
if (filter_off >= count) {
- ret = -ENOENT;
+ filter = ERR_PTR(-ENOENT);
goto out;
}
- count -= filter_off;
- filter = task->seccomp.filter;
- while (filter && count > 1) {
- filter = filter->prev;
+ count -= filter_off;
+ for (filter = orig; filter && count > 1; filter = filter->prev)
count--;
- }
if (WARN_ON(count != 1 || !filter)) {
- /* The filter tree shouldn't shrink while we're using it. */
- ret = -ENOENT;
+ filter = ERR_PTR(-ENOENT);
goto out;
}
+ __get_seccomp_filter(filter);
+
+out:
+ __put_seccomp_filter(orig);
+ return filter;
+}
+
+long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
+ void __user *data)
+{
+ struct seccomp_filter *filter;
+ struct sock_fprog_kern *fprog;
+ long ret;
+
+ if (!capable(CAP_SYS_ADMIN) ||
+ current->seccomp.mode != SECCOMP_MODE_DISABLED) {
+ return -EACCES;
+ }
+
+ filter = get_nth_filter(task, filter_off);
+ if (IS_ERR(filter))
+ return PTR_ERR(filter);
+
fprog = filter->prog->orig_prog;
if (!fprog) {
/* This must be a new non-cBPF filter, since we save
@@ -1034,17 +1053,11 @@ long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
if (!data)
goto out;
- __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(filter);
- return ret;
-
out:
- spin_unlock_irq(&task->sighand->siglock);
+ __put_seccomp_filter(filter);
return ret;
}
#endif
--
2.11.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v3 2/2] ptrace, seccomp: add support for retrieving seccomp metadata 2017-10-11 15:39 [PATCH v3 1/2] seccomp: hoist out filter resolving logic Tycho Andersen @ 2017-10-11 15:39 ` Tycho Andersen 2017-11-28 23:42 ` Kees Cook 2017-11-28 23:42 ` [PATCH v3 1/2] seccomp: hoist out filter resolving logic Kees Cook 1 sibling, 1 reply; 4+ messages in thread From: Tycho Andersen @ 2017-10-11 15:39 UTC (permalink / raw) To: Kees Cook; +Cc: linux-kernel, Tycho Andersen, Andy Lutomirski, Oleg Nesterov With the new SECCOMP_FILTER_FLAG_LOG, we need to be able to extract these flags for checkpoint restore, since they describe the state of a filter. So, let's add PTRACE_SECCOMP_GET_METADATA, similar to ..._GET_FILTER, which returns the metadata of the nth filter (right now, just the flags). Hopefully this will be future proof, and new per-filter metadata can be added to this struct. v3: * use GET_METADATA instead of GET_FLAGS Signed-off-by: Tycho Andersen <tycho@docker.com> CC: Kees Cook <keescook@chromium.org> CC: Andy Lutomirski <luto@amacapital.net> CC: Oleg Nesterov <oleg@redhat.com> --- include/linux/seccomp.h | 8 ++++++++ include/uapi/linux/ptrace.h | 6 ++++++ kernel/ptrace.c | 4 ++++ kernel/seccomp.c | 34 ++++++++++++++++++++++++++++++++++ 4 files changed, 52 insertions(+) diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index c8bef436b61d..a6dee99cd187 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -94,11 +94,19 @@ static inline void get_seccomp_filter(struct task_struct *tsk) #if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE) extern long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, void __user *data); +extern long seccomp_get_metadata(struct task_struct *task, + unsigned long filter_off, void __user *data); #else static inline long seccomp_get_filter(struct task_struct *task, unsigned long n, void __user *data) { return -EINVAL; } +static inline long seccomp_get_metadata(struct task_struct *task, + unsigned long filter_off, + void __user *data) +{ + return -EINVAL; +} #endif /* CONFIG_SECCOMP_FILTER && CONFIG_CHECKPOINT_RESTORE */ #endif /* _LINUX_SECCOMP_H */ diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h index fb8106509000..4e9774812dba 100644 --- a/include/uapi/linux/ptrace.h +++ b/include/uapi/linux/ptrace.h @@ -65,6 +65,12 @@ struct ptrace_peeksiginfo_args { #define PTRACE_SETSIGMASK 0x420b #define PTRACE_SECCOMP_GET_FILTER 0x420c +#define PTRACE_SECCOMP_GET_METADATA 0x420d + +struct seccomp_metadata { + unsigned long filter_off; /* Input: which filter */ + unsigned int flags; /* Output: filter's flags */ +}; /* Read signals from a shared (process wide) queue */ #define PTRACE_PEEKSIGINFO_SHARED (1 << 0) diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 84b1367935e4..58291e9f3276 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -1092,6 +1092,10 @@ int ptrace_request(struct task_struct *child, long request, ret = seccomp_get_filter(child, addr, datavp); break; + case PTRACE_SECCOMP_GET_METADATA: + ret = seccomp_get_metadata(child, addr, datavp); + break; + default: break; } diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 2e1568261ac4..ea762af4974d 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -1060,6 +1060,40 @@ long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, __put_seccomp_filter(filter); return ret; } + +long seccomp_get_metadata(struct task_struct *task, + unsigned long size, void __user *data) +{ + long ret; + struct seccomp_filter *filter; + struct seccomp_metadata kmd = {}; + + if (!capable(CAP_SYS_ADMIN) || + current->seccomp.mode != SECCOMP_MODE_DISABLED) { + return -EACCES; + } + + size = min_t(unsigned long, size, sizeof(kmd)); + + if (copy_from_user(&kmd, data, size)) + return -EFAULT; + + filter = get_nth_filter(task, kmd.filter_off); + if (IS_ERR(filter)) + return PTR_ERR(filter); + + memset(&kmd, 0, sizeof(kmd)); + if (filter->log) + kmd.flags |= SECCOMP_FILTER_FLAG_LOG; + + ret = size; + if (copy_to_user(data, &kmd, size)) + ret = -EFAULT; + + __put_seccomp_filter(filter); + return ret; + +} #endif #ifdef CONFIG_SYSCTL -- 2.11.0 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v3 2/2] ptrace, seccomp: add support for retrieving seccomp metadata 2017-10-11 15:39 ` [PATCH v3 2/2] ptrace, seccomp: add support for retrieving seccomp metadata Tycho Andersen @ 2017-11-28 23:42 ` Kees Cook 0 siblings, 0 replies; 4+ messages in thread From: Kees Cook @ 2017-11-28 23:42 UTC (permalink / raw) To: Tycho Andersen; +Cc: LKML, Andy Lutomirski, Oleg Nesterov On Wed, Oct 11, 2017 at 8:39 AM, Tycho Andersen <tycho@docker.com> wrote: > With the new SECCOMP_FILTER_FLAG_LOG, we need to be able to extract these > flags for checkpoint restore, since they describe the state of a filter. > > So, let's add PTRACE_SECCOMP_GET_METADATA, similar to ..._GET_FILTER, which > returns the metadata of the nth filter (right now, just the flags). > Hopefully this will be future proof, and new per-filter metadata can be > added to this struct. > > v3: * use GET_METADATA instead of GET_FLAGS > > Signed-off-by: Tycho Andersen <tycho@docker.com> > CC: Kees Cook <keescook@chromium.org> > CC: Andy Lutomirski <luto@amacapital.net> > CC: Oleg Nesterov <oleg@redhat.com> Applied for -next (with a minor whitespace fix). Thanks! -Kees > --- > include/linux/seccomp.h | 8 ++++++++ > include/uapi/linux/ptrace.h | 6 ++++++ > kernel/ptrace.c | 4 ++++ > kernel/seccomp.c | 34 ++++++++++++++++++++++++++++++++++ > 4 files changed, 52 insertions(+) > > diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h > index c8bef436b61d..a6dee99cd187 100644 > --- a/include/linux/seccomp.h > +++ b/include/linux/seccomp.h > @@ -94,11 +94,19 @@ static inline void get_seccomp_filter(struct task_struct *tsk) > #if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE) > extern long seccomp_get_filter(struct task_struct *task, > unsigned long filter_off, void __user *data); > +extern long seccomp_get_metadata(struct task_struct *task, > + unsigned long filter_off, void __user *data); > #else > static inline long seccomp_get_filter(struct task_struct *task, > unsigned long n, void __user *data) > { > return -EINVAL; > } > +static inline long seccomp_get_metadata(struct task_struct *task, > + unsigned long filter_off, > + void __user *data) > +{ > + return -EINVAL; > +} > #endif /* CONFIG_SECCOMP_FILTER && CONFIG_CHECKPOINT_RESTORE */ > #endif /* _LINUX_SECCOMP_H */ > diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h > index fb8106509000..4e9774812dba 100644 > --- a/include/uapi/linux/ptrace.h > +++ b/include/uapi/linux/ptrace.h > @@ -65,6 +65,12 @@ struct ptrace_peeksiginfo_args { > #define PTRACE_SETSIGMASK 0x420b > > #define PTRACE_SECCOMP_GET_FILTER 0x420c > +#define PTRACE_SECCOMP_GET_METADATA 0x420d > + > +struct seccomp_metadata { > + unsigned long filter_off; /* Input: which filter */ > + unsigned int flags; /* Output: filter's flags */ > +}; > > /* Read signals from a shared (process wide) queue */ > #define PTRACE_PEEKSIGINFO_SHARED (1 << 0) > diff --git a/kernel/ptrace.c b/kernel/ptrace.c > index 84b1367935e4..58291e9f3276 100644 > --- a/kernel/ptrace.c > +++ b/kernel/ptrace.c > @@ -1092,6 +1092,10 @@ int ptrace_request(struct task_struct *child, long request, > ret = seccomp_get_filter(child, addr, datavp); > break; > > + case PTRACE_SECCOMP_GET_METADATA: > + ret = seccomp_get_metadata(child, addr, datavp); > + break; > + > default: > break; > } > diff --git a/kernel/seccomp.c b/kernel/seccomp.c > index 2e1568261ac4..ea762af4974d 100644 > --- a/kernel/seccomp.c > +++ b/kernel/seccomp.c > @@ -1060,6 +1060,40 @@ long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, > __put_seccomp_filter(filter); > return ret; > } > + > +long seccomp_get_metadata(struct task_struct *task, > + unsigned long size, void __user *data) > +{ > + long ret; > + struct seccomp_filter *filter; > + struct seccomp_metadata kmd = {}; > + > + if (!capable(CAP_SYS_ADMIN) || > + current->seccomp.mode != SECCOMP_MODE_DISABLED) { > + return -EACCES; > + } > + > + size = min_t(unsigned long, size, sizeof(kmd)); > + > + if (copy_from_user(&kmd, data, size)) > + return -EFAULT; > + > + filter = get_nth_filter(task, kmd.filter_off); > + if (IS_ERR(filter)) > + return PTR_ERR(filter); > + > + memset(&kmd, 0, sizeof(kmd)); > + if (filter->log) > + kmd.flags |= SECCOMP_FILTER_FLAG_LOG; > + > + ret = size; > + if (copy_to_user(data, &kmd, size)) > + ret = -EFAULT; > + > + __put_seccomp_filter(filter); > + return ret; > + > +} > #endif > > #ifdef CONFIG_SYSCTL > -- > 2.11.0 > -- Kees Cook Pixel Security ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3 1/2] seccomp: hoist out filter resolving logic 2017-10-11 15:39 [PATCH v3 1/2] seccomp: hoist out filter resolving logic Tycho Andersen 2017-10-11 15:39 ` [PATCH v3 2/2] ptrace, seccomp: add support for retrieving seccomp metadata Tycho Andersen @ 2017-11-28 23:42 ` Kees Cook 1 sibling, 0 replies; 4+ messages in thread From: Kees Cook @ 2017-11-28 23:42 UTC (permalink / raw) To: Tycho Andersen; +Cc: LKML, Andy Lutomirski, Oleg Nesterov On Wed, Oct 11, 2017 at 8:39 AM, Tycho Andersen <tycho@docker.com> wrote: > Hoist out the nth filter resolving logic that ptrace uses into a new > function. We'll use this in the next patch to implement the new > PTRACE_SECCOMP_GET_FILTER_FLAGS command. > > v3: * significantly revamp get_nth_filter logic (Oleg) > * rebase on 4.14-rc4, using the new __{get,put}_seccomp_filter > primitives > > Signed-off-by: Tycho Andersen <tycho@docker.com> > CC: Kees Cook <keescook@chromium.org> > CC: Andy Lutomirski <luto@amacapital.net> > CC: Oleg Nesterov <oleg@redhat.com> Sorry for the giant delay in reviewing these. This all looks good, thanks! Applying for -next. -Kees > --- > kernel/seccomp.c | 77 +++++++++++++++++++++++++++++++++----------------------- > 1 file changed, 45 insertions(+), 32 deletions(-) > > diff --git a/kernel/seccomp.c b/kernel/seccomp.c > index bb3a38005b9c..2e1568261ac4 100644 > --- a/kernel/seccomp.c > +++ b/kernel/seccomp.c > @@ -977,49 +977,68 @@ long prctl_set_seccomp(unsigned long seccomp_mode, char __user *filter) > } > > #if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE) > -long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, > - void __user *data) > +static struct seccomp_filter *get_nth_filter(struct task_struct *task, > + unsigned long filter_off) > { > - struct seccomp_filter *filter; > - struct sock_fprog_kern *fprog; > - long ret; > - unsigned long count = 0; > - > - if (!capable(CAP_SYS_ADMIN) || > - current->seccomp.mode != SECCOMP_MODE_DISABLED) { > - return -EACCES; > - } > + struct seccomp_filter *orig, *filter; > + unsigned long count; > > + /* > + * Note: this is only correct because the caller should be the (ptrace) > + * tracer of the task, otherwise lock_task_sighand is needed. > + */ > spin_lock_irq(&task->sighand->siglock); > + > if (task->seccomp.mode != SECCOMP_MODE_FILTER) { > - ret = -EINVAL; > - goto out; > + spin_unlock_irq(&task->sighand->siglock); > + return ERR_PTR(-EINVAL); > } > > - filter = task->seccomp.filter; > - while (filter) { > - filter = filter->prev; > + orig = task->seccomp.filter; > + __get_seccomp_filter(orig); > + spin_unlock_irq(&task->sighand->siglock); > + > + count = 0; > + for (filter = orig; filter; filter = filter->prev) > count++; > - } > > if (filter_off >= count) { > - ret = -ENOENT; > + filter = ERR_PTR(-ENOENT); > goto out; > } > - count -= filter_off; > > - filter = task->seccomp.filter; > - while (filter && count > 1) { > - filter = filter->prev; > + count -= filter_off; > + for (filter = orig; filter && count > 1; filter = filter->prev) > count--; > - } > > if (WARN_ON(count != 1 || !filter)) { > - /* The filter tree shouldn't shrink while we're using it. */ > - ret = -ENOENT; > + filter = ERR_PTR(-ENOENT); > goto out; > } > > + __get_seccomp_filter(filter); > + > +out: > + __put_seccomp_filter(orig); > + return filter; > +} > + > +long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, > + void __user *data) > +{ > + struct seccomp_filter *filter; > + struct sock_fprog_kern *fprog; > + long ret; > + > + if (!capable(CAP_SYS_ADMIN) || > + current->seccomp.mode != SECCOMP_MODE_DISABLED) { > + return -EACCES; > + } > + > + filter = get_nth_filter(task, filter_off); > + if (IS_ERR(filter)) > + return PTR_ERR(filter); > + > fprog = filter->prog->orig_prog; > if (!fprog) { > /* This must be a new non-cBPF filter, since we save > @@ -1034,17 +1053,11 @@ long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, > if (!data) > goto out; > > - __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(filter); > - return ret; > - > out: > - spin_unlock_irq(&task->sighand->siglock); > + __put_seccomp_filter(filter); > return ret; > } > #endif > -- > 2.11.0 > -- Kees Cook Pixel Security ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-11-28 23:42 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2017-10-11 15:39 [PATCH v3 1/2] seccomp: hoist out filter resolving logic Tycho Andersen 2017-10-11 15:39 ` [PATCH v3 2/2] ptrace, seccomp: add support for retrieving seccomp metadata Tycho Andersen 2017-11-28 23:42 ` Kees Cook 2017-11-28 23:42 ` [PATCH v3 1/2] seccomp: hoist out filter resolving logic Kees Cook
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