mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-09-10 05:11:55 -04:00
3125751cd1
Filesystem paths may expand fourfold when trace text escapes spaces and other untrusted bytes. A sufficiently long representation can exhaust the shared scratch sequence. A sibling __print_flags() helper may then return an unterminated one-past pointer because TP_printk() argument ordering is unspecified. Use a fixed budget rather than the scratch space available at call time, so output does not vary with sibling evaluation order. Limit an untrusted string to three quarters of the trace sequence, leaving the rest for sibling helpers and final event metadata. Compute and commit complete escaped output transactionally so an exact fill cannot consume the terminating NUL or poison the scratch sequence. For strings that exceed the limit, retain the largest prefix ending at a complete escape unit, then append a raw UTF-8 ellipsis. Keep the helper's existing octal fallback so complete values remain unchanged. Hex fallback would consume the same four bytes per escaped byte without increasing the prefix or strengthening the marker. ESCAPE_NAP renders every non-ASCII input byte in octal, so legitimate data cannot reproduce the marker without being escaped. Cc: Günther Noack <gnoack@google.com> Link: https://patch.msgid.link/20260907154401.124362-1-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>