4.4-stable review patch. If anyone has any objections, please let me know.
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From: Oleg Nesterov oleg@redhat.com
commit 90718e32e1dcc2479acfa208ccfc6442850b594c upstream.
insn_get_length() has the side-effect of processing the entire instruction but only if it was decoded successfully, otherwise insn_complete() can fail and in this case we need to just return an error without warning.
Reported-by: syzbot+30d675e3ca03c1c351e7@syzkaller.appspotmail.com Signed-off-by: Oleg Nesterov oleg@redhat.com Reviewed-by: Masami Hiramatsu mhiramat@kernel.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: syzkaller-bugs@googlegroups.com Link: https://lkml.kernel.org/lkml/20180518162739.GA5559@redhat.com Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/uprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -290,7 +290,7 @@ static int uprobe_init_insn(struct arch_ insn_init(insn, auprobe->insn, sizeof(auprobe->insn), x86_64); /* has the side-effect of processing the entire instruction */ insn_get_length(insn); - if (WARN_ON_ONCE(!insn_complete(insn))) + if (!insn_complete(insn)) return -ENOEXEC;
if (is_prefix_bad(insn))