diff options
| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2022-01-10 23:15:29 +0000 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2022-04-13 12:15:51 -0700 |
| commit | ab502103ae3ce4c0fc393e598455efede3e523c9 (patch) | |
| tree | 76cc3109c004c93473f70759b100ac083ff03649 | |
| parent | 0aef499f3172a60222ae7460d61b364c134d6e1a (diff) | |
mm/usercopy: Detect large folio overruns
Move the compound page overrun detection out of
CONFIG_HARDENED_USERCOPY_PAGESPAN and convert it to use folios so it's
enabled for more people.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220110231530.665970-4-willy@infradead.org
| -rw-r--r-- | mm/usercopy.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/mm/usercopy.c b/mm/usercopy.c index e1e856dca124..9458c2b24b02 100644 --- a/mm/usercopy.c +++ b/mm/usercopy.c @@ -164,7 +164,6 @@ static inline void check_page_span(const void *ptr, unsigned long n, { #ifdef CONFIG_HARDENED_USERCOPY_PAGESPAN const void *end = ptr + n - 1; - struct page *endpage; bool is_reserved, is_cma; /* @@ -195,11 +194,6 @@ static inline void check_page_span(const void *ptr, unsigned long n, ((unsigned long)end & (unsigned long)PAGE_MASK))) return; - /* Allow if fully inside the same compound (__GFP_COMP) page. */ - endpage = virt_to_head_page(end); - if (likely(endpage == page)) - return; - /* * Reject if range is entirely either Reserved (i.e. special or * device memory), or CMA. Otherwise, reject since the object spans @@ -259,6 +253,10 @@ static inline void check_heap_object(const void *ptr, unsigned long n, if (folio_test_slab(folio)) { /* Check slab allocator for flags and size. */ __check_heap_object(ptr, n, folio_slab(folio), to_user); + } else if (folio_test_large(folio)) { + unsigned long offset = ptr - folio_address(folio); + if (offset + n > folio_size(folio)) + usercopy_abort("page alloc", NULL, to_user, offset, n); } else { /* Verify object does not incorrectly span multiple pages. */ check_page_span(ptr, n, folio_page(folio, 0), to_user); |