4.4-stable review patch. If anyone has any objections, please let me know. ------------------ commit ba093a6d9397da8eafcfbaa7d95bd34255da39a0 upstream. The vm_brk() alignment calculations should refuse to overflow. The ELF loader depending on this, but it has been fixed now. No other unsafe callers have been found. Link: http://lkml.kernel.org/r/1468014494-25291-3-git-send-email-keescook@xxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Reported-by: Hector Marco-Gisbert <hecmargi@xxxxxx> Cc: Ismael Ripoll Ripoll <iripoll@xxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Chen Gang <gang.chen.5i5j@xxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Konstantin Khlebnikov <koct9i@xxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> [bwh: Backported to 4.4: adjust context] Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- mm/mmap.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 39f5fbd07486..dd9205542a86 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2808,16 +2808,18 @@ static inline void verify_mm_writelocked(struct mm_struct *mm) * anonymous maps. eventually we may be able to do some * brk-specific accounting here. */ -static unsigned long do_brk(unsigned long addr, unsigned long len) +static unsigned long do_brk(unsigned long addr, unsigned long request) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma, *prev; - unsigned long flags; + unsigned long flags, len; struct rb_node **rb_link, *rb_parent; pgoff_t pgoff = addr >> PAGE_SHIFT; int error; - len = PAGE_ALIGN(len); + len = PAGE_ALIGN(request); + if (len < request) + return -ENOMEM; if (!len) return addr; -- 2.17.1
