From 04425e40b427d9f0469d9db9321839d434a3580b Mon Sep 17 00:00:00 2001 From: "Chris (Christopher) Brand" Date: Fri, 17 Jul 2015 20:48:08 +0000 Subject: [PATCH] xen: arm: Avoid reading beyond the last module nr_mods is set in add_boot_module() to the number of module array elements used. This function also ensures that nr_mods never exceeds MAX_MODULES (the size of the array). When looping through the array, the correct maximum index is "nr_mods-1", not "nr_mods". If the array is full, using the latter will in fact access beyond the end of the array. This was done correctly in boot_module_find_by_kind() and consider_modules() but incorrectly in discard_initial_modules() and next_module(). Signed-off-by: Chris Brand Reviewed-by: Julien Grall Acked-by: Ian Campbell --- xen/arch/arm/setup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c index a46c583e1a..6626eba70e 100644 --- a/xen/arch/arm/setup.c +++ b/xen/arch/arm/setup.c @@ -250,7 +250,7 @@ void __init discard_initial_modules(void) struct bootmodules *mi = &bootinfo.modules; int i; - for ( i = 0; i <= mi->nr_mods; i++ ) + for ( i = 0; i < mi->nr_mods; i++ ) { paddr_t s = mi->module[i].start; paddr_t e = s + PAGE_ALIGN(mi->module[i].size); @@ -350,7 +350,7 @@ static paddr_t __init next_module(paddr_t s, paddr_t *end) paddr_t lowest = ~(paddr_t)0; int i; - for ( i = 0; i <= mi->nr_mods; i++ ) + for ( i = 0; i < mi->nr_mods; i++ ) { paddr_t mod_s = mi->module[i].start; paddr_t mod_e = mod_s + mi->module[i].size; -- 2.30.2