kernel/linux.git/drivers/target/iscsi, branch v6.12.93

scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd()

2026-06-09T10:26:04+00:00

[ Upstream commit 778c2ab142c625a8a8afa570e0f9b7873f445d99 ] Two latent bugs in the Text-phase handler, both present since the original LIO integration in commit e48354ce078c ("iscsi-target: Add iSCSI fabric support for target v4.1"): 1) DataDigest CRC buffer overread (4 bytes past text_in). text_in is kzalloc()'d at ALIGN(payload_length, 4). rx_size is then incremented by ISCSI_CRC_LEN to make room for the received DataDigest in the iovec, but the same (now-bumped) rx_size is passed as the buffer length to iscsit_crc_buf(): if (conn->conn_ops->DataDigest) { ... rx_size += ISCSI_CRC_LEN; } ... if (conn->conn_ops->DataDigest) { data_crc = iscsit_crc_buf(text_in, rx_size, 0, NULL); iscsit_crc_buf() walks rx_size bytes of text_in with crc32c(), so when DataDigest is negotiated it reads 4 bytes past the end of the text_in allocation. KASAN reproduces this directly on the unpatched mainline tree as slab-out-of-bounds in crc32c() called from the Text PDU path. The OOB bytes feed crc32c() and are then compared against the initiator-supplied checksum, so the value does not flow back to the attacker, but the kernel does read past the buffer on every Text PDU with DataDigest=CRC32C. Fix by passing the actual padded payload length (ALIGN(payload_length, 4)) that was used for the kzalloc(). 2) Stale cmd->text_in_ptr re-free (double-free) on ERL>0 bad DataDigest drop. On DataDigest mismatch with ErrorRecoveryLevel > 0 the handler silently drops the PDU and lets the initiator plug the CmdSN gap: kfree(text_in); return 0; cmd->text_in_ptr still points at the freed buffer. The next Text Request on the same ITT re-enters iscsit_setup_text_cmd(), which unconditionally does kfree(cmd->text_in_ptr); cmd->text_in_ptr = NULL; freeing the same pointer a second time. Session teardown via iscsit_release_cmd() has the same shape and hits the same double-free if the connection is dropped before a second Text Request arrives. On an unmodified mainline tree the bug-1 CRC overread fires first on the initial valid Text Request and perturbs the subsequent state, so #4 was isolated by building a kernel with only the bug-1 hunk of this patch applied plus temporary printk() observability around the three relevant kfree() sites. The observability prints are not part of this patch. On that build, a three-PDU Text Request sequence after login produces two back-to-back splats: BUG: KASAN: double-free in iscsit_setup_text_cmd+0x?? BUG: KASAN: double-free in iscsit_release_cmd+0x?? showing the same pointer freed in the ERL>0 drop path and again in iscsit_setup_text_cmd() (next Text Request on the same ITT) and once more in iscsit_release_cmd() (session teardown). On distro kernels with CONFIG_SLAB_FREELIST_HARDENED=y (default) the double-free becomes a remote kernel BUG(); on non-hardened kernels it corrupts the slab freelist. Fix by clearing cmd->text_in_ptr after the kfree() in the ERL>0 drop path. With both hunks applied #4 is directly observable on the stock tree without observability printks; fixing bug-1 alone would mask #4 less, not more, so the hunks are submitted together. Both fixes are one-liners. The Text PDU state machine is unchanged and the wire protocol is unaffected. Fixes: e48354ce078c ("iscsi-target: Add iSCSI fabric support for target v4.1") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Tested-by: John Garry Reviewed-by: John Garry Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

scsi: target: iscsi: Validate CHAP_R length before base64 decode

2026-06-09T10:25:59+00:00

commit 85db7391310b1304d2dc8ae3b0b12105a9567147 upstream. chap_server_compute_hash() allocates client_digest as kzalloc(chap->digest_size) and then, for BASE64-encoded responses, passes chap_r directly to chap_base64_decode() without checking whether the input length could produce more than digest_size bytes of output. chap_base64_decode() writes to the destination unconditionally as long as there is input to consume. With MAX_RESPONSE_LENGTH set to 128 and the "0b" prefix stripped by extract_param(), up to 127 base64 characters can reach the decoder. 127 characters decode to 95 bytes. For SHA-256 (digest_size=32) this overflows client_digest by 63 bytes; for MD5 (digest_size=16) the overflow is 79 bytes. The length check at line 344 fires after the write has already happened. The HEX branch in the same switch statement already validates the length up front. Apply the same approach to the BASE64 branch: strip trailing base64 padding characters, then reject any input whose data length exceeds DIV_ROUND_UP(digest_size * 4, 3) before calling the decoder. Stripping trailing '=' before the comparison handles both padded and unpadded encodings. chap_base64_decode() already returns early on '=', so the full original string is still passed to the decoder unchanged. The mutual CHAP path decodes CHAP_C into initiatorchg_binhex, which is kzalloc(CHAP_CHALLENGE_STR_LEN). extract_param() caps initiatorchg at CHAP_CHALLENGE_STR_LEN characters, so at most CHAP_CHALLENGE_STR_LEN-1 base64 characters reach the decoder. The maximum decoded size, DIV_ROUND_UP((CHAP_CHALLENGE_STR_LEN-1) * 3, 4), is less than CHAP_CHALLENGE_STR_LEN, so no overflow is possible there. A comment is added at the call site to document this. Fixes: 1e5733883421 ("scsi: target: iscsi: Support base64 in CHAP") Cc: stable@vger.kernel.org Signed-off-by: Alexandru Hossu Reviewed-by: David Disseldorp Link: https://patch.msgid.link/20260521151121.808477-1-hossu.alexandru@gmail.com Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf

2026-06-09T10:25:59+00:00

commit bf33e01f88388c43e285492a63e539df6ffed64c upstream. iscsi_encode_text_output() concatenates "key=value\0" records into login->rsp_buf, an 8192-byte kzalloc(MAX_KEY_VALUE_PAIRS) buffer allocated in iscsit_alloc_login_setup_buffer(). The three sprintf() call sites in this function (lines 1398, 1411, 1424 in v7.1-rc2) never check the remaining buffer capacity: *length += sprintf(output_buf, "%s=%s", er->key, er->value); *length += 1; output_buf = textbuf + *length; The 8192-byte ceiling at iscsi_target_check_login_request() bounds the *input* Login PDU payload, but a single PDU can carry up to 2048 minimal four-byte "a=b\0" pairs, each unknown key expanding to a 16-byte "a=NotUnderstood\0" output record via iscsi_add_notunderstood_response(). 2048 * 16 = 32 KiB of output into an 8 KiB buffer, producing a ~24 KiB heap overrun in the kmalloc-8k slab. The fix introduces a static iscsi_encode_text_record() helper that uses snprintf() with a per-call bounds check against the remaining buffer, and threads a u32 textbuf_size parameter through iscsi_encode_text_output(). Both call sites in iscsi_target_handle_csg_zero() (PHASE_SECURITY) and iscsi_target_handle_csg_one() (PHASE_OPERATIONAL) pass MAX_KEY_VALUE_PAIRS. On overflow the encoder logs the condition, calls iscsi_release_extra_responses() to drop queued records, and returns -1; both caller sites now emit ISCSI_STATUS_CLS_INITIATOR_ERR / ISCSI_LOGIN_STATUS_INIT_ERR via iscsit_tx_login_rsp() before returning, so the initiator sees an explicit failed-login response rather than a silent connection drop. (Prior to this patch only the PHASE_OPERATIONAL caller did that; the PHASE_SECURITY caller is converted to the same shape.) Fixes: e48354ce078c ("iscsi-target: Add iSCSI fabric support for target v4.1") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Tested-by: John Garry Reviewed-by: John Garry Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: target: iscsi: Fix use-after-free in iscsit_dec_conn_usage_count()

2026-02-11T12:40:23+00:00

[ Upstream commit 9411a89e9e7135cc459178fa77a3f1d6191ae903 ] In iscsit_dec_conn_usage_count(), the function calls complete() while holding the conn->conn_usage_lock. As soon as complete() is invoked, the waiter (such as iscsit_close_connection()) may wake up and proceed to free the iscsit_conn structure. If the waiter frees the memory before the current thread reaches spin_unlock_bh(), it results in a KASAN slab-use-after-free as the function attempts to release a lock within the already-freed connection structure. Fix this by releasing the spinlock before calling complete(). Signed-off-by: Maurizio Lombardi Reported-by: Zhaojuan Guo Reviewed-by: Mike Christie Link: https://patch.msgid.link/20260112165352.138606-2-mlombard@redhat.com Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

scsi: target: iscsi: Fix use-after-free in iscsit_dec_session_usage_count()

2026-02-11T12:40:23+00:00

[ Upstream commit 84dc6037390b8607c5551047d3970336cb51ba9a ] In iscsit_dec_session_usage_count(), the function calls complete() while holding the sess->session_usage_lock. Similar to the connection usage count logic, the waiter signaled by complete() (e.g., in the session release path) may wake up and free the iscsit_session structure immediately. This creates a race condition where the current thread may attempt to execute spin_unlock_bh() on a session structure that has already been deallocated, resulting in a KASAN slab-use-after-free. To resolve this, release the session_usage_lock before calling complete() to ensure all dereferences of the sess pointer are finished before the waiter is allowed to proceed with deallocation. Signed-off-by: Maurizio Lombardi Reported-by: Zhaojuan Guo Reviewed-by: Mike Christie Link: https://patch.msgid.link/20260112165352.138606-3-mlombard@redhat.com Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

scsi: target: iscsi: Fix timeout on deleted connection

2025-05-29T09:01:58+00:00

[ Upstream commit 7f533cc5ee4c4436cee51dc58e81dfd9c3384418 ] NOPIN response timer may expire on a deleted connection and crash with such logs: Did not receive response to NOPIN on CID: 0, failing connection for I_T Nexus (null),i,0x00023d000125,iqn.2017-01.com.iscsi.target,t,0x3d BUG: Kernel NULL pointer dereference on read at 0x00000000 NIP strlcpy+0x8/0xb0 LR iscsit_fill_cxn_timeout_err_stats+0x5c/0xc0 [iscsi_target_mod] Call Trace: iscsit_handle_nopin_response_timeout+0xfc/0x120 [iscsi_target_mod] call_timer_fn+0x58/0x1f0 run_timer_softirq+0x740/0x860 __do_softirq+0x16c/0x420 irq_exit+0x188/0x1c0 timer_interrupt+0x184/0x410 That is because nopin response timer may be re-started on nopin timer expiration. Stop nopin timer before stopping the nopin response timer to be sure that no one of them will be re-started. Signed-off-by: Dmitry Bogdanov Link: https://lore.kernel.org/r/20241224101757.32300-1-d.bogdanov@yadro.com Reviewed-by: Maurizio Lombardi Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23+00:00

asm/unaligned.h is always an include of asm-generic/unaligned.h; might as well move that thing to linux/unaligned.h and include that - there's nothing arch-specific in that header. auto-generated by the following: for i in `git grep -l -w asm/unaligned.h`; do sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i done for i in `git grep -l -w asm-generic/unaligned.h`; do sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i done git mv include/asm-generic/unaligned.h include/linux/unaligned.h git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h

scsi: target: Remove unused declarations

2024-08-23T01:15:21+00:00

Commit 13247018d68f ("scsi: target: iscsi: Fix hang in the iSCSI login code") removed iscsi_handle_login_thread_timeout() but left declaration. Commit 3e1c81a95f0d ("iscsi-target: Refactor RX PDU logic + export request PDU handling") left iscsi_target_get_initial_payload() declaration. Commit d703ce2f7f4d ("iscsi/iser-target: Convert to command priv_size usage") remove iscsit_alloc_cmd() but left declaration. And finally, a few other declarations were never implenmented since introduction in commit e48354ce078c ("iscsi-target: Add iSCSI fabric support for target v4.1"). Signed-off-by: Yue Haibing Link: https://lore.kernel.org/r/20240810093437.2586476-1-yuehaibing@huawei.com Signed-off-by: Martin K. Petersen

scsi: target: iscsi: Remove unused variable xfer_len

2024-03-10T22:01:34+00:00

The variable 'xfer_len' is being initialized and incremented but it is never actually referenced in any other way. The variable is redundant and can be removed. Cleans up clang scan build warning: drivers/target/iscsi/iscsi_target_erl1.c:586:45: warning: variable 'xfer_len' set but not used [-Wunused-but-set-variable] Signed-off-by: Colin Ian King Link: https://lore.kernel.org/r/20240307104553.1980860-1-colin.i.king@gmail.com Signed-off-by: Martin K. Petersen

Merge patch series "scsi: target: Allow userspace to config cmd submission"

2023-10-13T19:56:37+00:00

Mike Christie says: The following patches were made over Linus's tree but apply over Martin's branches. They allow userspace to configure how fabric drivers submit cmds to backend drivers. Right now loop and vhost use a worker thread, and the other drivers submit from the contexts they receive/process the cmd from. For multiple LUN cases where the target can queue more cmds than the backend can handle then deferring to a worker thread is safest because the backend driver can block when doing things like waiting for a free request/tag. Deferring also helps when the target has to handle transport level requests from the recv context. For cases where the backend devices can queue everything the target sends, then there is no need to defer to a workqueue and you can see a perf boost of up to 26% for small IO workloads. For a nvme device and vhost-scsi I can see with 4K IOs: fio jobs 1 2 4 8 10 -------------------------------------------------- workqueue submit 94K 190K 394K 770K 890K direct submit 128K 252K 488K 950K - Link: https://lore.kernel.org/r/1b1f7a5c-0988-45f9-b103-dfed2c0405b1@oracle.com Signed-off-by: Martin K. Petersen