CVE-2024-57930: tracing: Have process_string() also allow arrays
Description
In the Linux kernel, the following vulnerability has been resolved:
tracing: Have process_string() also allow arrays
In order to catch a common bug where a TRACE_EVENT() TP_fast_assign()
assigns an address of an allocated string to the ring buffer and then
references it in TP_printk(), which can be executed hours later when the
string is free, the function test_event_printk() runs on all events as
they are registered to make sure there's no unwanted dereferencing.
It calls process_string() to handle cases in TP_printk() format that has
"%s". It returns whether or not the string is safe. But it can have some
false positives.
For instance, xe_bo_move() has:
TP_printk("move_lacks_source:%s, migrate object %p [size %zu] from %s to %s device_id:%s",
__entry->move_lacks_source ? "yes" : "no", __entry->bo, __entry->size,
xe_mem_type_to_name[__entry->old_placement],
xe_mem_type_to_name[__entry->new_placement], __get_str(device_id))
Where the "%s" references into xe_mem_type_to_name[]. This is an array of
pointers that should be safe for the event to access. Instead of flagging
this as a bad reference, if a reference points to an array, where the
record field is the index, consider it safe.
Classification
CVE ID: CVE-2024-57930
Affected Products
Vendor: Linux
Product: Linux
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.05% (probability of being exploited)
EPSS Percentile: 17.98% (scored less or equal to compared to others)
EPSS Date: 2025-02-19 (when was this score calculated)
References
https://git.kernel.org/stable/c/3bcdc9039a6e9e6e47ed689a37b8d57894a3c571https://git.kernel.org/stable/c/631b1e09e213c86d5a4ce23d45c81af473bb0ac7
https://git.kernel.org/stable/c/a64e5295ebc4afdefe69cdf16cc286a60ff8ba4b
https://git.kernel.org/stable/c/92bd18c74624e5eb9f96e70076aa46293f4b626f
https://git.kernel.org/stable/c/afc6717628f959941d7b33728570568b4af1c4b8