From d8b789ca13e5bccc3167d0cfa6cec3ff4b541891 Mon Sep 17 00:00:00 2001 From: Stephen Rothwell Date: Fri, 3 Nov 2006 14:42:43 +1100 Subject: [PATCH] Fix sys_move_pages when a NULL node list is passed. sys_move_pages() uses vmalloc() to allocate an array of structures that is fills with information passed from user mode and then passes to do_stat_pages() (in the case the node list is NULL). do_stat_pages() depends on a marker in the node field of the structure to decide how large the array is and this marker is correctly inserted into the last element of the array. However, vmalloc() doesn't zero the memory it allocates and if the user passes NULL for the node list, then the node fields are not filled in (except for the end marker). If the memory the vmalloc() returned happend to have a word with the marker value in it in just the right place, do_pages_stat will fail to fill the status field of part of the array and we will return (random) kernel data to user mode. Signed-off-by: Stephen Rothwell Acked-by: Christoph Lameter Signed-off-by: Chris Wright --- mm/migrate.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/migrate.c b/mm/migrate.c index 3f1e0c2c942c..fd280460e2c7 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -950,7 +950,8 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages, goto out; pm[i].node = node; - } + } else + pm[i].node = 0; /* anything to not match MAX_NUMNODES */ } /* End marker */ pm[nr_pages].node = MAX_NUMNODES; -- cgit v1.2.3