Messages in this thread | | | Subject | Re: [PATCH 1/3] x86/sev-es: Fix not using prefixes.nbytes for loop over prefixes.bytes | From | Tom Lendacky <> | Date | Wed, 2 Dec 2020 09:31:57 -0600 |
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On 12/2/20 2:51 AM, Masami Hiramatsu wrote: > 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. > > Fixes: 25189d08e516 ("x86/sev-es: Add support for handling IOIO exceptions") > Reported-by: Kees Cook <keescook@chromium.org> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > --- > arch/x86/boot/compressed/sev-es.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/boot/compressed/sev-es.c b/arch/x86/boot/compressed/sev-es.c > index 954cb2702e23..6a7a3027c9ac 100644 > --- a/arch/x86/boot/compressed/sev-es.c > +++ b/arch/x86/boot/compressed/sev-es.c > @@ -36,7 +36,7 @@ static bool insn_has_rep_prefix(struct insn *insn) > > insn_get_prefixes(insn); > > - for (i = 0; i < insn->prefixes.nbytes; i++) { > + for (i = 0; insn->prefixes.bytes[i] && i < 4; i++) {
Wouldn't it be better to create a #define for the size rather than hard coding 4 in the various files? That would protect everything should the bytes array size ever change in the future.
Thanks, Tom
> insn_byte_t p = insn->prefixes.bytes[i]; > > if (p == 0xf2 || p == 0xf3) >
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