diff options
Diffstat (limited to 'runtime/addr-map.c')
| -rw-r--r-- | runtime/addr-map.c | 45 |
1 files changed, 35 insertions, 10 deletions
diff --git a/runtime/addr-map.c b/runtime/addr-map.c index e898044f..8c0e84d8 100644 --- a/runtime/addr-map.c +++ b/runtime/addr-map.c @@ -1,6 +1,6 @@ /* -*- linux-c -*- * Map of addresses to disallow. - * Copyright (C) 2005-2008 Red Hat Inc. + * Copyright (C) 2005-2009 Red Hat Inc. * * This file is part of systemtap, and is free software. You can * redistribute it and/or modify it under the terms of the GNU General @@ -59,28 +59,41 @@ upper_bound(unsigned long addr, struct addr_map* map) return entry - &map->entries[0]; } +/* Search for an entry in the given map which overlaps the range specified by + addr and size. */ static struct addr_map_entry* -lookup_addr_aux(unsigned long addr, struct addr_map* map) +lookup_addr_aux(unsigned long addr, size_t size, struct addr_map* map) { size_t start = 0; size_t end; + + /* No map? No matching entry. */ if (!map) return 0; - end = map->size; + /* Empty map? No matching entry. */ if (map->size == 0) return 0; + /* Use binary search on the sorted map entries. */ + end = map->size; do { int entry_idx; struct addr_map_entry *entry = 0; - if (addr < map->entries[start].min || addr >= map->entries[end - 1].max) + /* If the target range is beyond those of the remaining entries in the + map, then a matching entry will not be found */ + if (addr + size <= map->entries[start].min || + addr >= map->entries[end - 1].max) return 0; + /* Choose the map entry at the mid point of the remaining entries. */ entry_idx = (end + start) / 2; entry = &map->entries[entry_idx]; - if (entry->min <= addr && entry->max > addr) + /* If our range overlaps the range of this entry, then we have a match. */ + if (addr + size > entry->min && addr < entry->max) return entry; - if (addr < entry->min) + /* If our range is below the range of this entry, then cull the entries + above this entry, otherwise cull the entries below it. */ + if (addr + size <= entry->min) end = entry_idx; else start = entry_idx + 1; @@ -88,12 +101,24 @@ lookup_addr_aux(unsigned long addr, struct addr_map* map) return 0; } +#ifndef STP_PRIVILEGED +#include <asm/processor.h> /* For TASK_SIZE */ +#endif + static int -lookup_bad_addr(unsigned long addr) +lookup_bad_addr(unsigned long addr, size_t size) { struct addr_map_entry* result = 0; + +#ifndef STP_PRIVILEGED + /* Unprivileged users must not access kernel space memory. */ + if (addr + size > TASK_SIZE) + return 1; +#endif + + /* Search for the given range in the black-listed map. */ spin_lock(&addr_map_lock); - result = lookup_addr_aux(addr, blackmap); + result = lookup_addr_aux(addr, size, blackmap); spin_unlock(&addr_map_lock); if (result) return 1; @@ -149,8 +174,8 @@ add_bad_addr_entry(unsigned long min_addr, unsigned long max_addr, } else { - min_entry = lookup_addr_aux(min_addr, blackmap); - max_entry = lookup_addr_aux(max_addr, blackmap); + min_entry = lookup_addr_aux(min_addr, 1, blackmap); + max_entry = lookup_addr_aux(max_addr, 1, blackmap); if (min_entry || max_entry) { if (existing_min) |