diff options
| author | Tycho Andersen <tycho@tycho.ws> | 2018-02-20 19:47:46 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2018-02-21 16:56:03 -0800 |
| commit | 63bb0045b98ae821e56e27c2250e14bb0ae663e5 (patch) | |
| tree | d26e642414ee3be9dbeb4d963b77a557eb62238b /kernel/seccomp.c | |
| parent | 2a040f9f39d3b020c79e08dec26d12a7ce131c10 (diff) | |
| download | lwn-63bb0045b98ae821e56e27c2250e14bb0ae663e5.tar.gz lwn-63bb0045b98ae821e56e27c2250e14bb0ae663e5.zip | |
ptrace, seccomp: tweak get_metadata behavior slightly
Previously if users passed a small size for the input structure size, they
would get get odd behavior. It doesn't make sense to pass a structure
smaller than at least filter_off size, so let's just give -EINVAL in this
case.
This changes userspace visible behavior, but was only introduced in commit
26500475ac1b ("ptrace, seccomp: add support for retrieving seccomp
metadata") in 4.16-rc2, so should be safe to change if merged before then.
Reported-by: Eugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: Tycho Andersen <tycho@tycho.ws>
CC: Kees Cook <keescook@chromium.org>
CC: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'kernel/seccomp.c')
| -rw-r--r-- | kernel/seccomp.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 61bd9dc260c8..1245b2338fff 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -1076,14 +1076,16 @@ long seccomp_get_metadata(struct task_struct *task, size = min_t(unsigned long, size, sizeof(kmd)); - if (copy_from_user(&kmd, data, size)) + if (size < sizeof(kmd.filter_off)) + return -EINVAL; + + if (copy_from_user(&kmd.filter_off, data, sizeof(kmd.filter_off))) 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; |