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authorSargun Dhillon <sargun@sargun.me>2019-12-28 22:24:50 -0800
committerKees Cook <keescook@chromium.org>2020-01-02 13:03:45 -0800
commit2882d53c9c6f3b8311d225062522f03772cf0179 (patch)
tree28a5e06d8dac7c2df05519ddd05c91a601767a5e /kernel
parent88c13f8bd71472fbab5338b01d99122908c77e53 (diff)
seccomp: Check that seccomp_notif is zeroed out by the user
This patch is a small change in enforcement of the uapi for SECCOMP_IOCTL_NOTIF_RECV ioctl. Specifically, the datastructure which is passed (seccomp_notif) must be zeroed out. Previously any of its members could be set to nonsense values, and we would ignore it. This ensures all fields are set to their zero value. Signed-off-by: Sargun Dhillon <sargun@sargun.me> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Aleksa Sarai <cyphar@cyphar.com> Acked-by: Tycho Andersen <tycho@tycho.ws> Link: https://lore.kernel.org/r/20191229062451.9467-2-sargun@sargun.me Fixes: 6a21cc50f0c7 ("seccomp: add a return code to trap to userspace") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/seccomp.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 12d2227e5786..b6ea3dcb57bf 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -1026,6 +1026,13 @@ static long seccomp_notify_recv(struct seccomp_filter *filter,
struct seccomp_notif unotif;
ssize_t ret;
+ /* Verify that we're not given garbage to keep struct extensible. */
+ ret = check_zeroed_user(buf, sizeof(unotif));
+ if (ret < 0)
+ return ret;
+ if (!ret)
+ return -EINVAL;
+
memset(&unotif, 0, sizeof(unotif));
ret = down_interruptible(&filter->notif->request);

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