* Masami Hiramatsu <[email protected]> [2020-12-02 17:51:16]: > 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: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove > uprobes breakpoints") > Cc: [email protected] > Reported-by: Kees Cook <[email protected]> > Signed-off-by: Masami Hiramatsu <[email protected]>
Looks good to me. Reviewed-by: Srikar Dronamraju <[email protected]> > --- > arch/x86/kernel/uprobes.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c > index 3fdaa042823d..bb3ea3705b99 100644 > --- a/arch/x86/kernel/uprobes.c > +++ b/arch/x86/kernel/uprobes.c > @@ -257,7 +257,7 @@ static bool is_prefix_bad(struct insn *insn) > { > int i; > > - for (i = 0; i < insn->prefixes.nbytes; i++) { > + for (i = 0; insn->prefixes.bytes[i] && i < 4; i++) { > insn_attr_t attr; > > attr = inat_get_opcode_attribute(insn->prefixes.bytes[i]); > @@ -746,7 +746,7 @@ static int branch_setup_xol_ops(struct arch_uprobe > *auprobe, struct insn *insn) > * Intel and AMD behavior differ in 64-bit mode: Intel ignores 66 > prefix. > * No one uses these insns, reject any branch insns with such prefix. > */ > - for (i = 0; i < insn->prefixes.nbytes; i++) { > + for (i = 0; insn->prefixes.bytes[i] && i < 4; i++) { > if (insn->prefixes.bytes[i] == 0x66) > return -ENOTSUPP; > } > -- Thanks and Regards Srikar Dronamraju
