From c45601306aa5831c3e59158f95b8e34f27e9ea09 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Sat, 26 Jul 2025 14:29:30 +0200 Subject: um: Don't mark stack executable On one of my machines UML failed to start after enabling SELinux. UML failed to start because SELinux's execmod rule denies executable pages on a modified file mapping. Historically UML marks it's stack rwx. AFAICT, these days this is no longer needed, so let's remove PROT_EXEC. Signed-off-by: Richard Weinberger Signed-off-by: Johannes Berg --- arch/um/os-Linux/util.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c index 4193e04d7e4a..e3ad71a0d13c 100644 --- a/arch/um/os-Linux/util.c +++ b/arch/um/os-Linux/util.c @@ -20,8 +20,7 @@ void stack_protections(unsigned long address) { - if (mprotect((void *) address, UM_THREAD_SIZE, - PROT_READ | PROT_WRITE | PROT_EXEC) < 0) + if (mprotect((void *) address, UM_THREAD_SIZE, PROT_READ | PROT_WRITE) < 0) panic("protecting stack failed, errno = %d", errno); } -- cgit v1.2.3 From 7ebf70cf181651fe3f2e44e95e7e5073d594c9c0 Mon Sep 17 00:00:00 2001 From: Miaoqian Lin Date: Thu, 28 Aug 2025 15:00:51 +0800 Subject: um: virtio_uml: Fix use-after-free after put_device in probe When register_virtio_device() fails in virtio_uml_probe(), the code sets vu_dev->registered = 1 even though the device was not successfully registered. This can lead to use-after-free or other issues. Fixes: 04e5b1fb0183 ("um: virtio: Remove device on disconnect") Signed-off-by: Miaoqian Lin Signed-off-by: Johannes Berg --- arch/um/drivers/virtio_uml.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c index ad8d78fb1d9a..de7867ae220d 100644 --- a/arch/um/drivers/virtio_uml.c +++ b/arch/um/drivers/virtio_uml.c @@ -1250,10 +1250,12 @@ static int virtio_uml_probe(struct platform_device *pdev) device_set_wakeup_capable(&vu_dev->vdev.dev, true); rc = register_virtio_device(&vu_dev->vdev); - if (rc) + if (rc) { put_device(&vu_dev->vdev.dev); + return rc; + } vu_dev->registered = 1; - return rc; + return 0; error_init: os_close_file(vu_dev->sock); -- cgit v1.2.3 From df447a3b4a4b961c9979b4b3ffb74317394b9b40 Mon Sep 17 00:00:00 2001 From: Tiwei Bie Date: Mon, 1 Sep 2025 08:27:15 +0800 Subject: um: Fix FD copy size in os_rcv_fd_msg() When copying FDs, the copy size should not include the control message header (cmsghdr). Fix it. Fixes: 5cde6096a4dd ("um: generalize os_rcv_fd") Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg --- arch/um/os-Linux/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c index 617886d1fb1e..21f0e50fb1df 100644 --- a/arch/um/os-Linux/file.c +++ b/arch/um/os-Linux/file.c @@ -535,7 +535,7 @@ ssize_t os_rcv_fd_msg(int fd, int *fds, unsigned int n_fds, cmsg->cmsg_type != SCM_RIGHTS) return n; - memcpy(fds, CMSG_DATA(cmsg), cmsg->cmsg_len); + memcpy(fds, CMSG_DATA(cmsg), cmsg->cmsg_len - CMSG_LEN(0)); return n; } -- cgit v1.2.3