Bug 2379257 (CVE-2025-38328)

Summary: CVE-2025-38328 kernel: Linux kernel (jffs2): Denial of Service via invalid pointer dereference
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the Linux kernel's jffs2 filesystem. A local user could trigger a system crash by performing specific filesystem operations. This occurs because the kernel does not properly validate memory allocation during certain operations, leading to an invalid memory access. Successful exploitation can result in a Denial of Service (DoS).
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Description OSIDB Bzimport 2025-07-10 09:03:24 UTC 
In the Linux kernel, the following vulnerability has been resolved:

jffs2: check jffs2_prealloc_raw_node_refs() result in few other places

Fuzzing hit another invalid pointer dereference due to the lack of
checking whether jffs2_prealloc_raw_node_refs() completed successfully.
Subsequent logic implies that the node refs have been allocated.

Handle that. The code is ready for propagating the error upwards.

KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 5835 Comm: syz-executor145 Not tainted 5.10.234-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:jffs2_link_node_ref+0xac/0x690 fs/jffs2/nodelist.c:600
Call Trace:
 jffs2_mark_erased_block fs/jffs2/erase.c:460 [inline]
 jffs2_erase_pending_blocks+0x688/0x1860 fs/jffs2/erase.c:118
 jffs2_garbage_collect_pass+0x638/0x1a00 fs/jffs2/gc.c:253
 jffs2_reserve_space+0x3f4/0xad0 fs/jffs2/nodemgmt.c:167
 jffs2_write_inode_range+0x246/0xb50 fs/jffs2/write.c:362
 jffs2_write_end+0x712/0x1110 fs/jffs2/file.c:302
 generic_perform_write+0x2c2/0x500 mm/filemap.c:3347
 __generic_file_write_iter+0x252/0x610 mm/filemap.c:3465
 generic_file_write_iter+0xdb/0x230 mm/filemap.c:3497
 call_write_iter include/linux/fs.h:2039 [inline]
 do_iter_readv_writev+0x46d/0x750 fs/read_write.c:740
 do_iter_write+0x18c/0x710 fs/read_write.c:866
 vfs_writev+0x1db/0x6a0 fs/read_write.c:939
 do_pwritev fs/read_write.c:1036 [inline]
 __do_sys_pwritev fs/read_write.c:1083 [inline]
 __se_sys_pwritev fs/read_write.c:1078 [inline]
 __x64_sys_pwritev+0x235/0x310 fs/read_write.c:1078
 do_syscall_64+0x30/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Comment 1 Avinash Hanwate 2025-07-10 10:40:52 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025071032-CVE-2025-38328-43bf@gregkh/T