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CVE-2025-38194

Description

In the Linux kernel, the following vulnerability has been resolved:jffs2: check that raw node were preallocated before writing summarySyzkaller detected a kernel bug in jffs2_link_node_ref, caused by faultinjection in jffs2_prealloc_raw_node_refs. jffs2_sum_write_sumnode doesn'tcheck return value of jffs2_prealloc_raw_node_refs and simply lets anyerror propagate into jffs2_sum_write_data, which eventually callsjffs2_link_node_ref in order to link the summary to an expectedly allocatednode.kernel BUG at fs/jffs2/nodelist.c:592!invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTICPU: 1 PID: 31277 Comm: syz-executor.7 Not tainted 6.1.128-syzkaller-00139-ge10f83ca10a1 #0Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014RIP: 0010:jffs2_link_node_ref+0x570/0x690 fs/jffs2/nodelist.c:592Call Trace: jffs2_sum_write_data fs/jffs2/summary.c:841 [inline] jffs2_sum_write_sumnode+0xd1a/0x1da0 fs/jffs2/summary.c:874 jffs2_do_reserve_space+0xa18/0xd60 fs/jffs2/nodemgmt.c:388 jffs2_reserve_space+0x55f/0xaa0 fs/jffs2/nodemgmt.c:197 jffs2_write_inode_range+0x246/0xb50 fs/jffs2/write.c:362 jffs2_write_end+0x726/0x15d0 fs/jffs2/file.c:301 generic_perform_write+0x314/0x5d0 mm/filemap.c:3856 __generic_file_write_iter+0x2ae/0x4d0 mm/filemap.c:3973 generic_file_write_iter+0xe3/0x350 mm/filemap.c:4005 call_write_iter include/linux/fs.h:2265 [inline] do_iter_readv_writev+0x20f/0x3c0 fs/read_write.c:735 do_iter_write+0x186/0x710 fs/read_write.c:861 vfs_iter_write+0x70/0xa0 fs/read_write.c:902 iter_file_splice_write+0x73b/0xc90 fs/splice.c:685 do_splice_from fs/splice.c:763 [inline] direct_splice_actor+0x10c/0x170 fs/splice.c:950 splice_direct_to_actor+0x337/0xa10 fs/splice.c:896 do_splice_direct+0x1a9/0x280 fs/splice.c:1002 do_sendfile+0xb13/0x12c0 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1323 [inline] __se_sys_sendfile64 fs/read_write.c:1309 [inline] __x64_sys_sendfile64+0x1cf/0x210 fs/read_write.c:1309 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x6e/0xd8Fix this issue by checking return value of jffs2_prealloc_raw_node_refsbefore calling jffs2_sum_write_data.Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

POC

Reference

No PoCs from references.

Github

- https://github.com/w4zu/Debian_security