kernel/linux.git/drivers/s390, branch v7.1.12

s390/zcrypt: Pad trailing CCA or EP11 message with zeros

2026-08-23T12:29:25+00:00

commit eb363254472493e3458156fc11fd56dca92f4333 upstream. The both functions xcrb_msg_to_type6cprb_msgx() and xcrb_msg_to_type6_ep11cprb_msgx() copy the user space message into a kernel buffer based on the message length. But on further processing the message is supposed to be 4 byte length adjusted. Thus up to 3 bytes of uninitialized kernel memory are forwarded to further processing steps and may unwanted expose kernel memory to the crypto card firmware. This patch contains code to pad the gap between user space copied message and message buffer length sent down to further processing of the CCA or EP11 message to zeros. Fixes: e2c6d91eb8b1 ("s390/zcrypt: Rework domain processing within zcrypt device driver") Signed-off-by: Harald Freudenberger Reviewed-by: Holger Dengler Cc: stable@vger.kernel.org # 7.1+ Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/zcrypt: Improve EP11 CPRB domain handling with ASN.1 parsing

2026-08-23T12:29:25+00:00

commit 0864a163783bff109b548266921829ea794edc93 upstream. The zcrypt_msgtype6_send_ep11_cprb() function uses fragile struct overlays to access and modify the domain field in the EP11 CPRB payload, creating maintainability and security concerns: 1. Struct overlay approach (pld_hdr) assumes fixed payload structure and doesn't validate the actual ASN.1 encoding. 2. Complex length format detection logic is error-prone and doesn't properly validate bounds at each parsing step. 3. Direct struct member access bypasses proper ASN.1 validation. Fix by replacing struct overlays with explicit ASN.1 parsing that validates each field (payload tag/length, function tag/length/value, optional domain tag/length/value) with proper bounds checking at every step. Add asn1_int_encode() helper function to safely write integer values with correct endianness conversion. This makes the code consistent with the validation pattern introduced with the rework of the xcrb_msg_to_type6_ep11cprb_msgx() function. Fixes: e2c6d91eb8b1 ("s390/zcrypt: Rework domain processing within zcrypt device driver") Signed-off-by: Harald Freudenberger Cc: stable@vger.kernel.org # 7.1+ Reviewed-by: Holger Dengler Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/zcrypt: Improve EP11 CPRB length and overflow checks

2026-08-23T12:29:25+00:00

commit 17ac0bc866fc624cd05f022dcd8b730c0af11bb1 upstream. The xcrb_msg_to_type6_ep11cprb_msgx() function lacks proper input validation, creating security vulnerabilities: 1. Missing minimum size validation: The ep11_cprb structure and subsequent payload fields (pld_tag, pld_lenfmt) are copied from userspace without verifying sufficient buffer length. 2. Arithmetic overflow in length calculations: CEIL4 alignment could overflow, bypassing size checks and enabling buffer overflows. 3. The payload is asn1 encoded but the function just uses a simple c struct overlay to access some fields of the payload. Fix by using size_t for length calculations, adding U32_MAX boundary checks after alignment, and validating minimum request size and minimum reply size before copying from userspace. Do a very simple asn1 parsing of the payload up to the function value field. Fixes: e2c6d91eb8b1 ("s390/zcrypt: Rework domain processing within zcrypt device driver") Signed-off-by: Harald Freudenberger Cc: stable@vger.kernel.org # 7.1+ Reviewed-by: Holger Dengler Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/zcrypt: Improve CCA CPRB length and overflow checks

2026-08-23T12:29:25+00:00

commit 35ac6754ba6da45fd193f5ce3f665f7490b830d5 upstream. The xcrb_msg_to_type6cprb_msgx() function lacks proper input validation, creating security vulnerabilities: 1. Integer overflow after CEIL4 alignment: Signed int variables could overflow during 4-byte boundary alignment, causing undersized buffer allocations or incorrect bounds checking. 2. Missing minimum size validation: The CPRBX structure is copied from userspace without verifying sufficient buffer length. Undersized buffers cause uninitialized memory access when reading structure fields like cprbx.cprb_len and cprbx.domain. 3. Arithmetic overflow in sum calculations: Adding control block and data block sizes could overflow, bypassing size checks and enabling buffer overflows. Fix by using size_t for length calculations, adding U32_MAX boundary checks after alignment, validating minimum control block size before copying from userspace, and detecting sum calculation overflows. Fixes: e2c6d91eb8b1 ("s390/zcrypt: Rework domain processing within zcrypt device driver") Signed-off-by: Harald Freudenberger Reviewed-by: Holger Dengler Cc: stable@vger.kernel.org # 7.1+ Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/zcrypt: Fix CPRB memory allocation in zcrypt misc code

2026-08-23T12:29:25+00:00

commit 5004889551dfaf7f4b2cda8ed213d234bb8ebf82 upstream. Both CPRB alloc functions in zcrypt_ccamisc.c and zcrypt_ep11misc.c did not round up the memory allocation to a multiple of 4 bytes as it is needed by the zcrypt layer to process the CPRBs. Now the alloc_and_prep_cprbmem() and alloc_cprbmem() functions guarantee that the base CPRB struct and a possible parameter block are aligned to a 4-byte boundary and the backing memory allocation is rounded up to the next multiple of 4 byte. Also the free_cprbmem() is updated and scrubs the rounded up amount of memory. Fixes: 9bdb5f7e8369 ("s390/zcrypt: Introduce cprb mempool for cca misc functions") Signed-off-by: Harald Freudenberger Reviewed-by: Holger Dengler Cc: stable@vger.kernel.org # 6.16+ Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/vfio_ccw: Implement a crw lock

2026-08-23T12:29:24+00:00

commit 16b0798024c0e9117e395829ddbbe70981c79d9c upstream. Unlike the channel_program struct, which covers synchronous I/O submissions and asynchronous interrupts, the CRW region relies exclusively on asynchronous events coming from hardware. Implement a lock to manage the list of those payloads, to ensure they are read cohesively. Fixes: 3f02cb2fd9d2 ("vfio-ccw: Wire up the CRW irq and CRW region") Cc: stable@vger.kernel.org Reviewed-by: Matthew Rosato Reviewed-by: Farhan Ali Signed-off-by: Eric Farman Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

s390/vfio_ccw: Calculate idal length based on idaw type

2026-08-23T12:29:24+00:00

commit 4f6fdc6e1a7fbfa36b945af33c65a417948feac0 upstream. Sashiko pointed out that get_guest_idal() unconditionally calculates the length of the IDAL presuming everything is a Format-2 IDAW. The output of vfio-ccw is always Format-2, but the input can be either Format-1 (31-bit addresses) or Format-2 (64-bit addresses). As a result, the size of the guest IDAL may be incorrect and should be trimmed down. Reported-by: sashiko-bot Link: https://lore.kernel.org/r/20260720203400.7328E1F000E9@smtp.kernel.org/ Fixes: 1b676fe3d9d3 ("vfio/ccw: handle a guest Format-1 IDAL") Cc: stable@vger.kernel.org Reviewed-by: Matthew Rosato Signed-off-by: Eric Farman Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

s390/vfio_ccw: Selectively expand io_mutex

2026-08-23T12:29:24+00:00

commit 34f4feff3e90bd09308fad0974e97113b23b812a upstream. The io_mutex was defined to serialize the io_regions, but then has also sort of been associated with the I/O themselves because of the close relationship they share. With the handful of races that are possible, the choices are either to: A) expand the scope of io_mutex to close these remaining windows, or B) reduce the scope of io_mutex to just io_region, and introduce a new lock mechanism for the remaining I/O resources This patch implements A, since B brings with it a lot more interactions that would need to be tracked and kept in a correct hierarchy. It also takes advantage of the workqueue element for cp_free() that now gets called out of fsm_notoper(), which could be invoked out of an interrupt context and thus cannot acquire a mutex itself. Fixes: 4f76617378ee ("vfio-ccw: protect the I/O region") Cc: stable@vger.kernel.org Signed-off-by: Eric Farman Reviewed-by: Matthew Rosato Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

s390/vfio_ccw: Move cp cleanup out of not operational

2026-08-23T12:29:24+00:00

commit 0c11f61a876ed6fcca53d442ed3f33ea8362a0f9 upstream. The fsm_notoper() routine is called when the device has been lost, and is (by definition) no longer operational. Since this can happen asynchronously from the normal behavior of the driver, the cleanup may happen when holding other locks in the calling sequence (notably, the cio subchannel lock). Push the cleanup of the private->cp resources to a workqueue, where it can be done out from under that lock sequence and a future patch can safely manage the locking requirements. Fixes: 204b394a23ad ("vfio/ccw: Move FSM open/close to MDEV open/close") Cc: stable@vger.kernel.org Signed-off-by: Eric Farman Reviewed-by: Matthew Rosato Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

s390/vfio_ccw: Fix out of bounds check on CCW array

2026-08-23T12:29:24+00:00

commit a005b7f1a491ffda61bff0fd0f6548f8986fb977 upstream. The routine ccwchain_calc_length() counts the number of channel command words (CCWs) that are chained together in a single channel program, and rejects anything larger than CCWCHAIN_LEN_MAX (256) CCWs. The loop itself is "do..while (count < 257)", and while the logic in is_cpa_within_range() correctly adjusts between the 0-index array of CCWs and the count of CCWs starting at 1, this means it would look at a possible 257th CCW before ending the loop and (correctly) returning an error. Fix this by restructuring the loop to break as soon as 256 CCWs (thus indexes 0-255) are examined, without looking at memory outside the range. Fixes: 0a19e61e6d4c ("vfio: ccw: introduce channel program interfaces") Cc: stable@vger.kernel.org Reviewed-by: Matthew Rosato Signed-off-by: Eric Farman Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman