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authorMasami Hiramatsu <mhiramat@kernel.org>2020-12-03 07:51:01 +0300
committerBorislav Petkov <bp@suse.de>2020-12-06 12:03:08 +0300
commit84da009f06e60cf59d5e861f8e2101d2d3885517 (patch)
tree65cc9d31679964de585d62db7a701ee112e1e703
parent12cb908a11b2544b5f53e9af856e6b6a90ed5533 (diff)
downloadlinux-84da009f06e60cf59d5e861f8e2101d2d3885517.tar.xz
x86/sev-es: Use new for_each_insn_prefix() macro to loop over prefixes bytes
Since insn.prefixes.nbytes can be bigger than the size of insn.prefixes.bytes[] when a prefix is repeated, the proper check must be: insn.prefixes.bytes[i] != 0 and i < 4 instead of using insn.prefixes.nbytes. Use the new for_each_insn_prefix() macro which does it correctly. Debugged by Kees Cook <keescook@chromium.org>. [ bp: Massage commit message. ] Fixes: 25189d08e516 ("x86/sev-es: Add support for handling IOIO exceptions") Reported-by: syzbot+9b64b619f10f19d19a7c@syzkaller.appspotmail.com Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/160697106089.3146288.2052422845039649176.stgit@devnote2
-rw-r--r--arch/x86/boot/compressed/sev-es.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/x86/boot/compressed/sev-es.c b/arch/x86/boot/compressed/sev-es.c
index 954cb2702e23..27826c265aab 100644
--- a/arch/x86/boot/compressed/sev-es.c
+++ b/arch/x86/boot/compressed/sev-es.c
@@ -32,13 +32,12 @@ struct ghcb *boot_ghcb;
*/
static bool insn_has_rep_prefix(struct insn *insn)
{
+ insn_byte_t p;
int i;
insn_get_prefixes(insn);
- for (i = 0; i < insn->prefixes.nbytes; i++) {
- insn_byte_t p = insn->prefixes.bytes[i];
-
+ for_each_insn_prefix(insn, i, p) {
if (p == 0xf2 || p == 0xf3)
return true;
}