In the Linux kernel, the following vulnerability has been resolved:
misc: fastrpc: fix use-after-free of fastrpc_user in workqueue context
There is a race between fastrpc_device_release() and the workqueue
that processes DSP responses. When the user closes the file descriptor,
fastrpc_device_release() frees the fastrpc_user structure. Concurrently,
an in-flight DSP invocation can complete and fastrpc_rpmsg_callback()
schedules context cleanup via schedule_work(&ctx->put_work). If the
workqueue runs fastrpc_context_free() in parallel with or after
fastrpc_device_release() has freed the user structure, it dereferences
the freed fastrpc_user. Depending on the state of the context at the
time of the race, any one of the following accesses can be hit:
1. fastrpc_buf_free() calls fastrpc_ipa_to_dma_addr(buf->fl->cctx, ...)
to strip the SID bits from the stored IOVA before passing the
physical address to dma_free_coherent().
2. fastrpc_free_map() reads map->fl->cctx->vmperms[0].vmid to
reconstruct the source permission bitmask needed for the
qcom_scm_assign_mem() call that returns memory from the DSP VM
back to HLOS.
3. fastrpc_free_map() acquires map->fl->lock to safely remove the
map node from the fl->maps list.
The resulting use-after-free manifests as:
pc : fastrpc_buf_free+0x38/0x80 [fastrpc]
lr : fastrpc_context_free+0xa8/0x1b0 [fastrpc]
fastrpc_context_free+0xa8/0x1b0 [fastrpc]
fastrpc_context_put_wq+0x78/0xa0 [fastrpc]
process_one_work+0x180/0x450
worker_thread+0x26c/0x388
Add kref-based reference counting to fastrpc_user. Have each invoke
context take a reference on the user at allocation time and release it
when the context is freed. Release the initial reference in
fastrpc_device_release() at file close. Move the teardown of the user
structure — freeing pending contexts, maps, mmaps, and the channel
context reference — into the kref release callback fastrpc_user_free(),
so that it runs only when the last reference is dropped, regardless of
whether that happens at device close or after the final in-flight
context completes.
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Validate XDomain request packet size before type cast
tb_xdp_handle_request() casts the received packet buffer to
protocol-specific structs without verifying that the allocation
is large enough for the target type. A peer can send a minimal
XDomain packet that passes the generic header length check but is
shorter than the struct accessed after the cast, causing out-of-
bounds reads from the kmemdup allocation.
Plumb the packet length through xdomain_request_work and validate
it against the expected struct size before each cast.
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Clamp XDomain response data copy to allocation size
tb_xdp_properties_request() derives the per-packet copy length from
the response header without checking that it fits in the previously
allocated data buffer. A malicious peer can set its length field
larger than the declared data_length, causing memcpy to write past
the kcalloc allocation.
Clamp the per-packet copy length so that the cumulative offset
never exceeds data_len.
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Bound root directory content to block size
__tb_property_parse_dir() does not check that content_offset +
content_len fits within block_len for the root directory case.
When rootdir->length equals or exceeds block_len - 2, the entry
loop reads past the allocated property block.
Add a bounds check after computing content_offset and content_len
to reject directories whose content extends past the block.
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Reject zero-length property entries in validator
tb_property_entry_valid() accepts entries with length == 0 for
DIRECTORY, DATA, and TEXT types. A zero-length TEXT entry passes
validation but causes an underflow in the null-termination logic:
property->value.text[property->length * 4 - 1] = '\0';
When property->length is 0 this writes to offset -1 relative to
the allocation.
Reject zero-length entries early in the validator since they have no
valid representation in the XDomain property protocol.
In the Linux kernel, the following vulnerability has been resolved:
nvmem: core: fix use-after-free bugs in error paths
Fix several instances of error paths in which we call
__nvmem_device_put() - which may end up freeing the underlying memory
and other resources - and then keep on using the nvmem structure. Always
put the reference to the nvmem device as the last step before returning
the error code.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Clamp HDMI HDCP2 rx_id_list read to buffer size
[Why & How]
During HDCP 2.x repeater authentication over HDMI, the driver reads the
sink's RxStatus register and extracts a 10-bit message size field (max
value 1023). This value is used as the read length for the ReceiverID
list without being clamped to the size of the destination buffer
rx_id_list[177]. A malicious HDMI repeater could advertise a message
size larger than the buffer, causing an out-of-bounds write during the
I2C read.
Clamp the read length in mod_hdcp_read_rx_id_list() to the size of the
rx_id_list buffer, matching the approach already used in the DP branch.
(cherry picked from commit 229212219e4247d9486f8ba41ef087358490be09)
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Bound VBIOS record-chain walk loops
[Why & How]
All record-chain walk loops in bios_parser.c and bios_parser2.c use
for(;;) and only terminate on a 0xFF record_type sentinel or zero
record_size. A malformed VBIOS image missing the terminator record
causes unbounded iteration at probe time, potentially hundreds of
thousands of iterations with record_size=1. In the final iterations
near the BIOS image boundary, struct casts beyond the 2-byte header
validated by GET_IMAGE can also read out of bounds.
Cap all 14 record-chain walk loops to BIOS_MAX_NUM_RECORD (256)
iterations. The atombios.h defines up to 22 distinct record types
and atomfirmware.h has 13. Assuming an average of less than 10
records per type (which is reasonable since most are connector-
based) 256 is a generous upper bound.
(cherry picked from commit 95700a3d660287ed657d6892f7be9ffc0e294a93)
In the Linux kernel, the following vulnerability has been resolved:
drm/v3d: Skip CSD when it has zeroed workgroups
A compute shader dispatch encodes its workgroup counts in the CFG0..CFG2
registers. Kicking off a dispatch with a zero count in any of the three
dimensions is invalid. First, the hardware will process 0 as 65536,
while the user-space driver exposes a maximum of 65535. Over that, a
submission with a zeroed workgroup dimension should be a no-op.
These zeroed counts can reach the dispatch path through an indirect CSD
job, whose workgroup counts are only known once the indirect buffer is
read and may legitimately be zero, but such scenario should only result in
a no-op.
Overwrite the indirect CSD job workgroup counts with the indirect BO
ones, even if they are zeroed, and don't submit the job to the hardware
when any of the workgroup counts is zero, so the job completes immediately
instead of running the shader.
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Limit XDomain response copy to actual frame size
tb_xdomain_copy() copies req->response_size bytes from the received
packet buffer regardless of the actual frame size. When a short
response arrives, this reads past the valid frame data in the DMA
pool buffer into stale contents from previous transactions.
Use the minimum of frame size and expected response size for the
copy length.