6.13-stable review patch. If anyone has any objections, please let me know.
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From: Paulo Alcantara pc@manguebit.com
[ Upstream commit 9502dd5c7029902f4a425bf959917a5a9e7c0e50 ]
After commit f7025d861694 ("smb: client: allocate crypto only for primary server") and commit b0abcd65ec54 ("smb: client: fix UAF in async decryption"), the channels started reusing AEAD TFM from primary channel to perform synchronous decryption, but that can't done as there could be multiple cifsd threads (one per channel) simultaneously accessing it to perform decryption.
This fixes the following KASAN splat when running fstest generic/249 with 'vers=3.1.1,multichannel,max_channels=4,seal' against Windows Server 2022:
BUG: KASAN: slab-use-after-free in gf128mul_4k_lle+0xba/0x110 Read of size 8 at addr ffff8881046c18a0 by task cifsd/986 CPU: 3 UID: 0 PID: 986 Comm: cifsd Not tainted 6.15.0-rc1 #1 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-3.fc41 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x5d/0x80 print_report+0x156/0x528 ? gf128mul_4k_lle+0xba/0x110 ? __virt_addr_valid+0x145/0x300 ? __phys_addr+0x46/0x90 ? gf128mul_4k_lle+0xba/0x110 kasan_report+0xdf/0x1a0 ? gf128mul_4k_lle+0xba/0x110 gf128mul_4k_lle+0xba/0x110 ghash_update+0x189/0x210 shash_ahash_update+0x295/0x370 ? __pfx_shash_ahash_update+0x10/0x10 ? __pfx_shash_ahash_update+0x10/0x10 ? __pfx_extract_iter_to_sg+0x10/0x10 ? ___kmalloc_large_node+0x10e/0x180 ? __asan_memset+0x23/0x50 crypto_ahash_update+0x3c/0xc0 gcm_hash_assoc_remain_continue+0x93/0xc0 crypt_message+0xe09/0xec0 [cifs] ? __pfx_crypt_message+0x10/0x10 [cifs] ? _raw_spin_unlock+0x23/0x40 ? __pfx_cifs_readv_from_socket+0x10/0x10 [cifs] decrypt_raw_data+0x229/0x380 [cifs] ? __pfx_decrypt_raw_data+0x10/0x10 [cifs] ? __pfx_cifs_read_iter_from_socket+0x10/0x10 [cifs] smb3_receive_transform+0x837/0xc80 [cifs] ? __pfx_smb3_receive_transform+0x10/0x10 [cifs] ? __pfx___might_resched+0x10/0x10 ? __pfx_smb3_is_transform_hdr+0x10/0x10 [cifs] cifs_demultiplex_thread+0x692/0x1570 [cifs] ? __pfx_cifs_demultiplex_thread+0x10/0x10 [cifs] ? rcu_is_watching+0x20/0x50 ? rcu_lockdep_current_cpu_online+0x62/0xb0 ? find_held_lock+0x32/0x90 ? kvm_sched_clock_read+0x11/0x20 ? local_clock_noinstr+0xd/0xd0 ? trace_irq_enable.constprop.0+0xa8/0xe0 ? __pfx_cifs_demultiplex_thread+0x10/0x10 [cifs] kthread+0x1fe/0x380 ? kthread+0x10f/0x380 ? __pfx_kthread+0x10/0x10 ? local_clock_noinstr+0xd/0xd0 ? ret_from_fork+0x1b/0x60 ? local_clock+0x15/0x30 ? lock_release+0x29b/0x390 ? rcu_is_watching+0x20/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x60 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK>
Tested-by: David Howells dhowells@redhat.com Reported-by: Steve French stfrench@microsoft.com Closes: https://lore.kernel.org/r/CAH2r5mu6Yc0-RJXM3kFyBYUB09XmXBrNodOiCVR4EDrmxq5Sz... Fixes: f7025d861694 ("smb: client: allocate crypto only for primary server") Fixes: b0abcd65ec54 ("smb: client: fix UAF in async decryption") Signed-off-by: Paulo Alcantara (Red Hat) pc@manguebit.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/smb/client/cifsencrypt.c | 16 +++++----------- fs/smb/client/smb2ops.c | 6 +++--- fs/smb/client/smb2pdu.c | 11 ++--------- 3 files changed, 10 insertions(+), 23 deletions(-)
diff --git a/fs/smb/client/cifsencrypt.c b/fs/smb/client/cifsencrypt.c index 7a43daacc8159..7c61c1e944c7a 100644 --- a/fs/smb/client/cifsencrypt.c +++ b/fs/smb/client/cifsencrypt.c @@ -702,18 +702,12 @@ cifs_crypto_secmech_release(struct TCP_Server_Info *server) cifs_free_hash(&server->secmech.md5); cifs_free_hash(&server->secmech.sha512);
- if (!SERVER_IS_CHAN(server)) { - if (server->secmech.enc) { - crypto_free_aead(server->secmech.enc); - server->secmech.enc = NULL; - } - - if (server->secmech.dec) { - crypto_free_aead(server->secmech.dec); - server->secmech.dec = NULL; - } - } else { + if (server->secmech.enc) { + crypto_free_aead(server->secmech.enc); server->secmech.enc = NULL; + } + if (server->secmech.dec) { + crypto_free_aead(server->secmech.dec); server->secmech.dec = NULL; } } diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index 17c3063a9ca5b..9bf0f498be19f 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -4549,9 +4549,9 @@ decrypt_raw_data(struct TCP_Server_Info *server, char *buf, return rc; } } else { - if (unlikely(!server->secmech.dec)) - return -EIO; - + rc = smb3_crypto_aead_allocate(server); + if (unlikely(rc)) + return rc; tfm = server->secmech.dec; }
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c index 23ae73c9c5e97..7b27acd94864d 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -1251,15 +1251,8 @@ SMB2_negotiate(const unsigned int xid, cifs_server_dbg(VFS, "Missing expected negotiate contexts\n"); }
- if (server->cipher_type && !rc) { - if (!SERVER_IS_CHAN(server)) { - rc = smb3_crypto_aead_allocate(server); - } else { - /* For channels, just reuse the primary server crypto secmech. */ - server->secmech.enc = server->primary_server->secmech.enc; - server->secmech.dec = server->primary_server->secmech.dec; - } - } + if (server->cipher_type && !rc) + rc = smb3_crypto_aead_allocate(server); neg_exit: free_rsp_buf(resp_buftype, rsp); return rc;