From 8ef618859c379fdce81c91bc93e0574e36ea76ff Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Fri, 5 Jun 2020 16:49:29 +0100 Subject: [PATCH] linux-user: detect overflow of MAP_FIXED mmap MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Relaxing the restrictions on 64 bit guests leads to the user being able to attempt to map right at the edge of addressable memory. This in turn lead to address overflow tripping the assert in page_set_flags when the end address wrapped around. Detect the wrap earlier and correctly -ENOMEM the guest (in the reported case LTP mmap15). Fixes: 7d8cbbabcb Signed-off-by: Alex Bennée Reported-by: Laurent Vivier Message-Id: <20200605154929.26910-15-alex.bennee@linaro.org> --- linux-user/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index caab62909e..0019447892 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -467,7 +467,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, * It can fail only on 64-bit host with 32-bit target. * On any other target/host host mmap() handles this error correctly. */ - if (!guest_range_valid(start, len)) { + if (end < start || !guest_range_valid(start, len)) { errno = ENOMEM; goto fail; }