From ab0cc25a4b0367227df10f18c98db96af2db1dc0 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 3 Jun 2011 07:45:28 +0300 Subject: [PATCH] xen: off by one errors in multicalls.c commit f124c6ae59e193705c9ddac57684d50006d710e6 upstream. b->args[] has MC_ARGS elements, so the comparison here should be ">=" instead of ">". Otherwise we read past the end of the array one space. Signed-off-by: Dan Carpenter Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- arch/x86/xen/multicalls.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c index 8bff7e7c290b..1b2b73ff0a6e 100644 --- a/arch/x86/xen/multicalls.c +++ b/arch/x86/xen/multicalls.c @@ -189,10 +189,10 @@ struct multicall_space __xen_mc_entry(size_t args) unsigned argidx = roundup(b->argidx, sizeof(u64)); BUG_ON(preemptible()); - BUG_ON(b->argidx > MC_ARGS); + BUG_ON(b->argidx >= MC_ARGS); if (b->mcidx == MC_BATCH || - (argidx + args) > MC_ARGS) { + (argidx + args) >= MC_ARGS) { mc_stats_flush(b->mcidx == MC_BATCH ? FL_SLOTS : FL_ARGS); xen_mc_flush(); argidx = roundup(b->argidx, sizeof(u64)); @@ -206,7 +206,7 @@ struct multicall_space __xen_mc_entry(size_t args) ret.args = &b->args[argidx]; b->argidx = argidx + args; - BUG_ON(b->argidx > MC_ARGS); + BUG_ON(b->argidx >= MC_ARGS); return ret; } @@ -216,7 +216,7 @@ struct multicall_space xen_mc_extend_args(unsigned long op, size_t size) struct multicall_space ret = { NULL, NULL }; BUG_ON(preemptible()); - BUG_ON(b->argidx > MC_ARGS); + BUG_ON(b->argidx >= MC_ARGS); if (b->mcidx == 0) return ret; @@ -224,14 +224,14 @@ struct multicall_space xen_mc_extend_args(unsigned long op, size_t size) if (b->entries[b->mcidx - 1].op != op) return ret; - if ((b->argidx + size) > MC_ARGS) + if ((b->argidx + size) >= MC_ARGS) return ret; ret.mc = &b->entries[b->mcidx - 1]; ret.args = &b->args[b->argidx]; b->argidx += size; - BUG_ON(b->argidx > MC_ARGS); + BUG_ON(b->argidx >= MC_ARGS); return ret; } -- 2.39.5