From: Chris (Christopher) Brand Date: Fri, 17 Jul 2015 20:48:08 +0000 (+0000) Subject: xen: arm: Avoid reading beyond the last module X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~2742 X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https://%22%22/%22http:/www.example.com/cgi/%22https:/%22%22?a=commitdiff_plain;h=04425e40b427d9f0469d9db9321839d434a3580b;p=xen.git 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 --- 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;