Hi,
Here are the patches to fix the wrong loop boundary check
on insn.prefixes.bytes[] array.
Kees Cook reported that this issue that there are similar
wrong boundary check patterns in the x86 code.
Since the insn.prefixes.nbytes can be bigger than the size of
insn.prefixes.bytes[] when a same prefix is repeated, we have to
check whether the insn.prefixes.bytes[i] != 0 (*) and i < 4 instead
of insn.prefixes.nbytes.
(*) Note that insn.prefixes.bytes[] should be zeroed in insn_init()
before decoding, and 0x00 is not a legacy prefix. So if you see 0
on insn.prefix.bytes[], it indicates the end of the array. Or,
if the prefixes.bytes[] is filled with prefix bytes, we can check
the index is less than 4.
Thank you,
---
Masami Hiramatsu (3):
x86/sev-es: Fix not using prefixes.nbytes for loop over prefixes.bytes
x86/uprobes: Fix not using prefixes.nbytes for loop over prefixes.bytes
x86/insn-eval: Fix not using prefixes.nbytes for loop over prefixes.bytes
arch/x86/boot/compressed/sev-es.c | 2 +-
arch/x86/kernel/uprobes.c | 4 ++--
arch/x86/lib/insn-eval.c | 4 ++--
3 files changed, 5 insertions(+), 5 deletions(-)
--
Masami Hiramatsu (Linaro) <[email protected]>
