From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- include/net/scm.h | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 include/net/scm.h (limited to 'include/net/scm.h') diff --git a/include/net/scm.h b/include/net/scm.h new file mode 100644 index 000000000..86ae6bc10 --- /dev/null +++ b/include/net/scm.h @@ -0,0 +1,114 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __LINUX_NET_SCM_H +#define __LINUX_NET_SCM_H + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Well, we should have at least one descriptor open + * to accept passed FDs 8) + */ +#define SCM_MAX_FD 253 + +struct scm_creds { + u32 pid; + kuid_t uid; + kgid_t gid; +}; + +#ifdef CONFIG_UNIX +struct unix_edge; +#endif + +struct scm_fp_list { + short count; + short count_unix; + short max; +#ifdef CONFIG_UNIX + bool inflight; + bool dead; + struct list_head vertices; + struct unix_edge *edges; +#endif + struct user_struct *user; + struct file *fp[SCM_MAX_FD]; +}; + +struct scm_cookie { + struct pid *pid; /* Skb credentials */ + struct scm_fp_list *fp; /* Passed files */ + struct scm_creds creds; /* Skb credentials */ +#ifdef CONFIG_SECURITY_NETWORK + u32 secid; /* Passed security ID */ +#endif +}; + +void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm, bool notrunc); +void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm, bool notrunc); +int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm); +void __scm_destroy(struct scm_cookie *scm); +struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl); + +#ifdef CONFIG_SECURITY_NETWORK +static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm) +{ + security_socket_getpeersec_dgram(sock, NULL, &scm->secid); +} +#else +static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm) +{ } +#endif /* CONFIG_SECURITY_NETWORK */ + +static __inline__ void scm_set_cred(struct scm_cookie *scm, + struct pid *pid, kuid_t uid, kgid_t gid) +{ + scm->pid = get_pid(pid); + scm->creds.pid = pid_vnr(pid); + scm->creds.uid = uid; + scm->creds.gid = gid; +} + +static __inline__ void scm_destroy_cred(struct scm_cookie *scm) +{ + put_pid(scm->pid); + scm->pid = NULL; +} + +static __inline__ void scm_destroy(struct scm_cookie *scm) +{ + scm_destroy_cred(scm); + if (scm->fp) + __scm_destroy(scm); +} + +static __inline__ int scm_send(struct socket *sock, struct msghdr *msg, + struct scm_cookie *scm, bool forcecreds) +{ + memset(scm, 0, sizeof(*scm)); + scm->creds.uid = INVALID_UID; + scm->creds.gid = INVALID_GID; + if (forcecreds) + scm_set_cred(scm, task_tgid(current), current_uid(), current_gid()); + unix_get_peersec_dgram(sock, scm); + if (msg->msg_controllen <= 0) + return 0; + return __scm_send(sock, msg, scm); +} + +void scm_recv(struct socket *sock, struct msghdr *msg, + struct scm_cookie *scm, int flags); +void scm_recv_unix(struct socket *sock, struct msghdr *msg, + struct scm_cookie *scm, int flags); + +int scm_recv_one_fd(struct file *f, int __user *ufd, unsigned int flags, + bool notrunc); + +#endif /* __LINUX_NET_SCM_H */ + -- cgit v1.3.1