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David Howells
a67632c8c2
Currently, trace_cachefiles_coherency() is being passed a pointer to a
__be64 lain over the coherency data in struct cachefiles_xattr so that it
can display the first 8 bytes. However, the data is of variable length and
could even be 0 bytes. This could lead to a UAF or KASAN warning.
Fix this by making sure the buffer has room for at least 8 bytes and that
those 8 bytes are pre-cleared.
Further, those bytes are not 8-byte aligned, so fix the tracepoint to
extract the data as four 2-byte words (they are 2-byte aligned) and
reassemble the __be64. The compiler will convert this into a single 8-byte
load where the CPU supports it.
Fixes: 229105e5cf ("cachefiles: Add auxiliary data trace")
Link: https://sashiko.dev/#/patchset/20260810144746.574036-1-dhowells%40redhat.com
Signed-off-by: David Howells <[email protected]>
Link: https://patch.msgid.link/[email protected]
Acked-by: Paulo Alcantara <[email protected]>
cc: Paulo Alcantara <[email protected]>
cc: [email protected]
cc: [email protected]
Signed-off-by: Christian Brauner (Amutable) <[email protected]>