diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2024-02-12 12:17:31 +0100 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2024-02-12 10:42:02 -0800 |
| commit | 56af94aace8a0489fb1a32fd6f1cf0c548fe3911 (patch) | |
| tree | 9ba2e24626a73f0174b21f17ed89367e2fdd86af | |
| parent | 55e68669b131401074513f903c097dae06ec6db1 (diff) | |
samples: user-trap: fix strict-aliasing warning
I started getting warnings for this one file, though I can't see what changed
since it was originally introduced in commit fec7b6690541 ("samples: add an
example of seccomp user trap").
samples/seccomp/user-trap.c: In function 'send_fd':
samples/seccomp/user-trap.c:50:11: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
50 | *((int *)CMSG_DATA(cmsg)) = fd;
| ~^~~~~~~~~~~~~~~~~~~~~~~
samples/seccomp/user-trap.c: In function 'recv_fd':
samples/seccomp/user-trap.c:83:18: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
83 | return *((int *)CMSG_DATA(cmsg));
| ~^~~~~~~~~~~~~~~~~~~~~~~
Using a temporary pointer variable avoids the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20240212111737.917428-1-arnd@kernel.org
Acked-by: Tycho Andersen <tandersen@netflix.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
| -rw-r--r-- | samples/seccomp/user-trap.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/samples/seccomp/user-trap.c b/samples/seccomp/user-trap.c index 20291ec6489f..a23fec357b5d 100644 --- a/samples/seccomp/user-trap.c +++ b/samples/seccomp/user-trap.c @@ -33,6 +33,7 @@ static int send_fd(int sock, int fd) { struct msghdr msg = {}; struct cmsghdr *cmsg; + int *fd_ptr; char buf[CMSG_SPACE(sizeof(int))] = {0}, c = 'c'; struct iovec io = { .iov_base = &c, @@ -47,7 +48,8 @@ static int send_fd(int sock, int fd) cmsg->cmsg_level = SOL_SOCKET; cmsg->cmsg_type = SCM_RIGHTS; cmsg->cmsg_len = CMSG_LEN(sizeof(int)); - *((int *)CMSG_DATA(cmsg)) = fd; + fd_ptr = (int *)CMSG_DATA(cmsg); + *fd_ptr = fd; msg.msg_controllen = cmsg->cmsg_len; if (sendmsg(sock, &msg, 0) < 0) { @@ -62,6 +64,7 @@ static int recv_fd(int sock) { struct msghdr msg = {}; struct cmsghdr *cmsg; + int *fd_ptr; char buf[CMSG_SPACE(sizeof(int))] = {0}, c = 'c'; struct iovec io = { .iov_base = &c, @@ -79,8 +82,9 @@ static int recv_fd(int sock) } cmsg = CMSG_FIRSTHDR(&msg); + fd_ptr = (int *)CMSG_DATA(cmsg); - return *((int *)CMSG_DATA(cmsg)); + return *fd_ptr; } static int user_trap_syscall(int nr, unsigned int flags) |