From a98b7761f697e590ed5d610d87fa12be66f23419 Mon Sep 17 00:00:00 2001 From: Tiwei Bie Date: Mon, 16 Sep 2024 12:59:48 +0800 Subject: [PATCH] um: Fix potential integer overflow during physmem setup This issue happens when the real map size is greater than LONG_MAX, which can be easily triggered on UML/i386. Fixes: fe205bdd1321 ("um: Print minimum physical memory requirement") Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20240916045950.508910-3-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg --- arch/um/kernel/physmem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c index fb2adfb499452..ee693e0b2b58b 100644 --- a/arch/um/kernel/physmem.c +++ b/arch/um/kernel/physmem.c @@ -81,10 +81,10 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end, unsigned long len, unsigned long long highmem) { unsigned long reserve = reserve_end - start; - long map_size = len - reserve; + unsigned long map_size = len - reserve; int err; - if(map_size <= 0) { + if (len <= reserve) { os_warn("Too few physical memory! Needed=%lu, given=%lu\n", reserve, len); exit(1); @@ -95,7 +95,7 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end, err = os_map_memory((void *) reserve_end, physmem_fd, reserve, map_size, 1, 1, 1); if (err < 0) { - os_warn("setup_physmem - mapping %ld bytes of memory at 0x%p " + os_warn("setup_physmem - mapping %lu bytes of memory at 0x%p " "failed - errno = %d\n", map_size, (void *) reserve_end, err); exit(1); -- 2.50.1