* [PATCH v4 1/2] seccomp: hoist out filter resolving logic
@ 2017-11-15 2:00 Tycho Andersen
2017-11-15 2:00 ` [PATCH v4 2/2] ptrace, seccomp: add support for retrieving seccomp metadata Tycho Andersen
0 siblings, 1 reply; 6+ messages in thread
From: Tycho Andersen @ 2017-11-15 2:00 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
v4: * resend
Signed-off-by: Tycho Andersen <tycho@tycho.ws>
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 418a1c045933..bad457862ee0 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -978,49 +978,68 @@ 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
@@ -1035,17 +1054,11 @@ 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
--
2.14.1
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH v4 2/2] ptrace, seccomp: add support for retrieving seccomp metadata 2017-11-15 2:00 [PATCH v4 1/2] seccomp: hoist out filter resolving logic Tycho Andersen @ 2017-11-15 2:00 ` Tycho Andersen 2018-02-20 19:30 ` Dmitry V. Levin 2018-02-20 20:13 ` Eugene Syromiatnikov 0 siblings, 2 replies; 6+ messages in thread From: Tycho Andersen @ 2017-11-15 2:00 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 v4: * resend Signed-off-by: Tycho Andersen <tycho@tycho.ws> 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 10f25f7e4304..c723a5c4e3ff 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -95,11 +95,19 @@ 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 e3939e00980b..e46d82b91166 100644 --- a/include/uapi/linux/ptrace.h +++ b/include/uapi/linux/ptrace.h @@ -66,6 +66,12 @@ 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 bad457862ee0..7f1f2f3ea549 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -1061,6 +1061,40 @@ 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 -- 2.14.1 ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v4 2/2] ptrace, seccomp: add support for retrieving seccomp metadata 2017-11-15 2:00 ` [PATCH v4 2/2] ptrace, seccomp: add support for retrieving seccomp metadata Tycho Andersen @ 2018-02-20 19:30 ` Dmitry V. Levin 2018-02-21 2:49 ` Tycho Andersen 2018-02-20 20:13 ` Eugene Syromiatnikov 1 sibling, 1 reply; 6+ messages in thread From: Dmitry V. Levin @ 2018-02-20 19:30 UTC (permalink / raw) To: Tycho Andersen Cc: Kees Cook, Andy Lutomirski, Oleg Nesterov, linux-api, linux-kernel [-- Attachment #1: Type: text/plain, Size: 1528 bytes --] Hi, On Tue, Nov 14, 2017 at 07:00:19PM -0700, Tycho Andersen 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 > v4: * resend > > Signed-off-by: Tycho Andersen <tycho@tycho.ws> > CC: Kees Cook <keescook@chromium.org> > CC: Andy Lutomirski <luto@amacapital.net> > CC: Oleg Nesterov <oleg@redhat.com> [...] > diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h > index e3939e00980b..e46d82b91166 100644 > --- a/include/uapi/linux/ptrace.h > +++ b/include/uapi/linux/ptrace.h > @@ -66,6 +66,12 @@ 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 */ > +}; This "unsigned long" field is unacceptable unless you are willing to implement a compat layer for this arch-dependent type. Please use an arch-independent type instead. See e.g. struct ptrace_peeksiginfo_args or struct struct seccomp_data. -- ldv [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 801 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v4 2/2] ptrace, seccomp: add support for retrieving seccomp metadata 2018-02-20 19:30 ` Dmitry V. Levin @ 2018-02-21 2:49 ` Tycho Andersen 0 siblings, 0 replies; 6+ messages in thread From: Tycho Andersen @ 2018-02-21 2:49 UTC (permalink / raw) To: Kees Cook, Andy Lutomirski, Oleg Nesterov, linux-api, linux-kernel On Tue, Feb 20, 2018 at 10:30:52PM +0300, Dmitry V. Levin wrote: > > +struct seccomp_metadata { > > + unsigned long filter_off; /* Input: which filter */ > > + unsigned int flags; /* Output: filter's flags */ > > +}; > > This "unsigned long" field is unacceptable unless you are willing > to implement a compat layer for this arch-dependent type. > > Please use an arch-independent type instead. > See e.g. struct ptrace_peeksiginfo_args or struct struct seccomp_data. Whoops, sorry about that. I believe I've addressed it in https://lkml.org/lkml/2018/2/20/755 Cheers, Tycho ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v4 2/2] ptrace, seccomp: add support for retrieving seccomp metadata 2017-11-15 2:00 ` [PATCH v4 2/2] ptrace, seccomp: add support for retrieving seccomp metadata Tycho Andersen 2018-02-20 19:30 ` Dmitry V. Levin @ 2018-02-20 20:13 ` Eugene Syromiatnikov 2018-02-21 2:50 ` Tycho Andersen 1 sibling, 1 reply; 6+ messages in thread From: Eugene Syromiatnikov @ 2018-02-20 20:13 UTC (permalink / raw) To: Tycho Andersen; +Cc: Kees Cook, linux-kernel, Andy Lutomirski, Oleg Nesterov On Tue, Nov 14, 2017 at 07:00:19PM -0700, Tycho Andersen 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 > v4: * resend > > Signed-off-by: Tycho Andersen <tycho@tycho.ws> > 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 10f25f7e4304..c723a5c4e3ff 100644 > --- a/include/linux/seccomp.h > +++ b/include/linux/seccomp.h > @@ -95,11 +95,19 @@ 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 e3939e00980b..e46d82b91166 100644 > --- a/include/uapi/linux/ptrace.h > +++ b/include/uapi/linux/ptrace.h > @@ -66,6 +66,12 @@ 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 bad457862ee0..7f1f2f3ea549 100644 > --- a/kernel/seccomp.c > +++ b/kernel/seccomp.c > @@ -1061,6 +1061,40 @@ 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; This will work kinda funny if size is less than sizeof(kmd.filter_off). And I see no reason for copying the whole structure when only filter_off is needed. > + > + filter = get_nth_filter(task, kmd.filter_off); > + if (IS_ERR(filter)) > + return PTR_ERR(filter); > + > + memset(&kmd, 0, sizeof(kmd)); Is rewriting the filter_off field to 0 intentional? > + 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 > -- > 2.14.1 > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v4 2/2] ptrace, seccomp: add support for retrieving seccomp metadata 2018-02-20 20:13 ` Eugene Syromiatnikov @ 2018-02-21 2:50 ` Tycho Andersen 0 siblings, 0 replies; 6+ messages in thread From: Tycho Andersen @ 2018-02-21 2:50 UTC (permalink / raw) To: Eugene Syromiatnikov Cc: Kees Cook, linux-kernel, Andy Lutomirski, Oleg Nesterov On Tue, Feb 20, 2018 at 09:13:28PM +0100, Eugene Syromiatnikov wrote: > On Tue, Nov 14, 2017 at 07:00:19PM -0700, Tycho Andersen 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 > > v4: * resend > > > > Signed-off-by: Tycho Andersen <tycho@tycho.ws> > > 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 10f25f7e4304..c723a5c4e3ff 100644 > > --- a/include/linux/seccomp.h > > +++ b/include/linux/seccomp.h > > @@ -95,11 +95,19 @@ 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 e3939e00980b..e46d82b91166 100644 > > --- a/include/uapi/linux/ptrace.h > > +++ b/include/uapi/linux/ptrace.h > > @@ -66,6 +66,12 @@ 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 bad457862ee0..7f1f2f3ea549 100644 > > --- a/kernel/seccomp.c > > +++ b/kernel/seccomp.c > > @@ -1061,6 +1061,40 @@ 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; > > This will work kinda funny if size is less than sizeof(kmd.filter_off). > And I see no reason for copying the whole structure when only filter_off > is needed. Yes, agreed. EINVAL seems better. > > + > > + filter = get_nth_filter(task, kmd.filter_off); > > + if (IS_ERR(filter)) > > + return PTR_ERR(filter); > > + > > + memset(&kmd, 0, sizeof(kmd)); > > Is rewriting the filter_off field to 0 intentional? It "shouldn't" matter, but it's probably better not to; I've fixed it in https://lkml.org/lkml/2018/2/20/755 Thanks! Tycho ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-02-21 2:50 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-11-15 2:00 [PATCH v4 1/2] seccomp: hoist out filter resolving logic Tycho Andersen 2017-11-15 2:00 ` [PATCH v4 2/2] ptrace, seccomp: add support for retrieving seccomp metadata Tycho Andersen 2018-02-20 19:30 ` Dmitry V. Levin 2018-02-21 2:49 ` Tycho Andersen 2018-02-20 20:13 ` Eugene Syromiatnikov 2018-02-21 2:50 ` Tycho Andersen
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