From ccd08e4d99fa607d7ad8fc0dc02329850ce24244 Mon Sep 17 00:00:00 2001 From: Gleb Smirnoff Date: Tue, 25 Oct 2016 17:13:46 +0000 Subject: [PATCH] The argument validation in r296956 was not enough to close all possible overflows in sysarch(2). Submitted by: Kun Yang Patch by: kib Security: SA-16:15 --- sys/amd64/amd64/sys_machdep.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/sys/amd64/amd64/sys_machdep.c b/sys/amd64/amd64/sys_machdep.c index 4f85e1f0317..24009dbaed5 100644 --- a/sys/amd64/amd64/sys_machdep.c +++ b/sys/amd64/amd64/sys_machdep.c @@ -608,6 +608,8 @@ amd64_set_ldt(td, uap, descs) largest_ld = uap->start + uap->num; if (largest_ld > max_ldt_segment) largest_ld = max_ldt_segment; + if (largest_ld < uap->start) + return (EINVAL); i = largest_ld - uap->start; mtx_lock(&dt_lock); bzero(&((struct user_segment_descriptor *)(pldt->ldt_base)) @@ -620,7 +622,8 @@ amd64_set_ldt(td, uap, descs) /* verify range of descriptors to modify */ largest_ld = uap->start + uap->num; if (uap->start >= max_ldt_segment || - largest_ld > max_ldt_segment) + largest_ld > max_ldt_segment || + largest_ld < uap->start) return (EINVAL); }