CVE-2025-40052
Fecha de publicación:
28/10/2025
*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br />
<br />
smb: client: fix crypto buffers in non-linear memory<br />
<br />
The crypto API, through the scatterlist API, expects input buffers to be<br />
in linear memory. We handle this with the cifs_sg_set_buf() helper<br />
that converts vmalloc&#39;d memory to their corresponding pages.<br />
<br />
However, when we allocate our aead_request buffer (@creq in<br />
smb2ops.c::crypt_message()), we do so with kvzalloc(), which possibly<br />
puts aead_request->__ctx in vmalloc area.<br />
<br />
AEAD algorithm then uses ->__ctx for its private/internal data and<br />
operations, and uses sg_set_buf() for such data on a few places.<br />
<br />
This works fine as long as @creq falls into kmalloc zone (small<br />
requests) or vmalloc&#39;d memory is still within linear range.<br />
<br />
Tasks&#39; stacks are vmalloc&#39;d by default (CONFIG_VMAP_STACK=y), so too<br />
many tasks will increment the base stacks&#39; addresses to a point where<br />
virt_addr_valid(buf) will fail (BUG() in sg_set_buf()) when that<br />
happens.<br />
<br />
In practice: too many parallel reads and writes on an encrypted mount<br />
will trigger this bug.<br />
<br />
To fix this, always alloc @creq with kmalloc() instead.<br />
Also drop the @sensitive_size variable/arguments since<br />
kfree_sensitive() doesn&#39;t need it.<br />
<br />
Backtrace:<br />
<br />
[ 945.272081] ------------[ cut here ]------------<br />
[ 945.272774] kernel BUG at include/linux/scatterlist.h:209!<br />
[ 945.273520] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI<br />
[ 945.274412] CPU: 7 UID: 0 PID: 56 Comm: kworker/u33:0 Kdump: loaded Not tainted 6.15.0-lku-11779-g8e9d6efccdd7-dirty #1 PREEMPT(voluntary)<br />
[ 945.275736] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-2-gc13ff2cd-prebuilt.qemu.org 04/01/2014<br />
[ 945.276877] Workqueue: writeback wb_workfn (flush-cifs-2)<br />
[ 945.277457] RIP: 0010:crypto_gcm_init_common+0x1f9/0x220<br />
[ 945.278018] Code: b0 00 00 00 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc 48 c7 c0 00 00 00 80 48 2b 05 5c 58 e5 00 e9 58 ff ff ff 0b 0f 0b 0f 0b 0f 0b 0f 0b 0f 0b 48 c7 04 24 01 00 00 00 48 8b<br />
[ 945.279992] RSP: 0018:ffffc90000a27360 EFLAGS: 00010246<br />
[ 945.280578] RAX: 0000000000000000 RBX: ffffc90001d85060 RCX: 0000000000000030<br />
[ 945.281376] RDX: 0000000000080000 RSI: 0000000000000000 RDI: ffffc90081d85070<br />
[ 945.282145] RBP: ffffc90001d85010 R08: ffffc90001d85000 R09: 0000000000000000<br />
[ 945.282898] R10: ffffc90001d85090 R11: 0000000000001000 R12: ffffc90001d85070<br />
[ 945.283656] R13: ffff888113522948 R14: ffffc90001d85060 R15: ffffc90001d85010<br />
[ 945.284407] FS: 0000000000000000(0000) GS:ffff8882e66cf000(0000) knlGS:0000000000000000<br />
[ 945.285262] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033<br />
[ 945.285884] CR2: 00007fa7ffdd31f4 CR3: 000000010540d000 CR4: 0000000000350ef0<br />
[ 945.286683] Call Trace:<br />
[ 945.286952] <br />
[ 945.287184] ? crypt_message+0x33f/0xad0 [cifs]<br />
[ 945.287719] crypto_gcm_encrypt+0x36/0xe0<br />
[ 945.288152] crypt_message+0x54a/0xad0 [cifs]<br />
[ 945.288724] smb3_init_transform_rq+0x277/0x300 [cifs]<br />
[ 945.289300] smb_send_rqst+0xa3/0x160 [cifs]<br />
[ 945.289944] cifs_call_async+0x178/0x340 [cifs]<br />
[ 945.290514] ? __pfx_smb2_writev_callback+0x10/0x10 [cifs]<br />
[ 945.291177] smb2_async_writev+0x3e3/0x670 [cifs]<br />
[ 945.291759] ? find_held_lock+0x32/0x90<br />
[ 945.292212] ? netfs_advance_write+0xf2/0x310<br />
[ 945.292723] netfs_advance_write+0xf2/0x310<br />
[ 945.293210] netfs_write_folio+0x346/0xcc0<br />
[ 945.293689] ? __pfx__raw_spin_unlock_irq+0x10/0x10<br />
[ 945.294250] netfs_writepages+0x117/0x460<br />
[ 945.294724] do_writepages+0xbe/0x170<br />
[ 945.295152] ? find_held_lock+0x32/0x90<br />
[ 945.295600] ? kvm_sched_clock_read+0x11/0x20<br />
[ 945.296103] __writeback_single_inode+0x56/0x4b0<br />
[ 945.296643] writeback_sb_inodes+0x229/0x550<br />
[ 945.297140] __writeback_inodes_wb+0x4c/0xe0<br />
[ 945.297642] wb_writeback+0x2f1/0x3f0<br />
[ 945.298069] wb_workfn+0x300/0x490<br />
[ 945.298472] process_one_work+0x1fe/0x590<br />
[ 945.298949] worker_thread+0x1ce/0x3c0<br />
[ 945.299397] ? __pfx_worker_thread+0x10/0x10<br />
[ 945.299900] kthr<br />
---truncated---
Gravedad: Pendiente de análisis
Última modificación:
30/10/2025