path: root/samples/seccomp
diff options
authorSargun Dhillon <sargun@sargun.me>2019-12-30 12:35:03 -0800
committerKees Cook <keescook@chromium.org>2020-01-02 13:03:39 -0800
commit771b894f2f3dfedc2ba5561731fffa0e39b1bbb6 (patch)
tree95902c0d8e6275f848b929faa0ed21fd6e7246e3 /samples/seccomp
parentLinux 5.5-rc4 (diff)
samples/seccomp: Zero out members based on seccomp_notif_sizes
The sizes by which seccomp_notif and seccomp_notif_resp are allocated are based on the SECCOMP_GET_NOTIF_SIZES ioctl. This allows for graceful extension of these datastructures. If userspace zeroes out the datastructure based on its version, and it is lagging behind the kernel's version, it will end up sending trailing garbage. On the other hand, if it is ahead of the kernel version, it will write extra zero space, and potentially cause corruption. Signed-off-by: Sargun Dhillon <sargun@sargun.me> Suggested-by: Tycho Andersen <tycho@tycho.ws> Link: https://lore.kernel.org/r/20191230203503.4925-1-sargun@sargun.me Fixes: fec7b6690541 ("samples: add an example of seccomp user trap") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'samples/seccomp')
1 files changed, 2 insertions, 2 deletions
diff --git a/samples/seccomp/user-trap.c b/samples/seccomp/user-trap.c
index 6d0125ca8af7..20291ec6489f 100644
--- a/samples/seccomp/user-trap.c
+++ b/samples/seccomp/user-trap.c
@@ -298,14 +298,14 @@ int main(void)
req = malloc(sizes.seccomp_notif);
if (!req)
goto out_close;
- memset(req, 0, sizeof(*req));
resp = malloc(sizes.seccomp_notif_resp);
if (!resp)
goto out_req;
- memset(resp, 0, sizeof(*resp));
+ memset(resp, 0, sizes.seccomp_notif_resp);
while (1) {
+ memset(req, 0, sizes.seccomp_notif);
if (ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, req)) {
perror("ioctl recv");
goto out_resp;