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authorArnd Bergmann <arnd@arndb.de>2024-02-12 12:17:31 +0100
committerKees Cook <keescook@chromium.org>2024-02-12 10:42:02 -0800
commit56af94aace8a0489fb1a32fd6f1cf0c548fe3911 (patch)
tree9ba2e24626a73f0174b21f17ed89367e2fdd86af /samples
parent55e68669b131401074513f903c097dae06ec6db1 (diff)
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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>
Diffstat (limited to 'samples')
-rw-r--r--samples/seccomp/user-trap.c8
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)