diff options
| author | Ingo Molnar <mingo@kernel.org> | 2016-09-15 08:24:53 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-09-15 08:24:53 +0200 |
| commit | d4b80afbba49e968623330f1336da8c724da8aad (patch) | |
| tree | a9478bd77d8b001a6a7119328d34e9666d7bfe93 /mm/usercopy.c | |
| parent | fcd709ef20a9d83bdb7524d27cd6719dac8690a0 (diff) | |
| parent | 4cea8776571b18db7485930cb422faa739580c8c (diff) | |
Merge branch 'linus' into x86/asm, to pick up recent fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/usercopy.c')
| -rw-r--r-- | mm/usercopy.c | 65 |
1 files changed, 37 insertions, 28 deletions
diff --git a/mm/usercopy.c b/mm/usercopy.c index 8ebae91a6b55..089328f2b920 100644 --- a/mm/usercopy.c +++ b/mm/usercopy.c @@ -83,7 +83,7 @@ static bool overlaps(const void *ptr, unsigned long n, unsigned long low, unsigned long check_high = check_low + n; /* Does not overlap if entirely above or entirely below. */ - if (check_low >= high || check_high < low) + if (check_low >= high || check_high <= low) return false; return true; @@ -124,7 +124,7 @@ static inline const char *check_kernel_text_object(const void *ptr, static inline const char *check_bogus_address(const void *ptr, unsigned long n) { /* Reject if object wraps past end of memory. */ - if (ptr + n < ptr) + if ((unsigned long)ptr + n < (unsigned long)ptr) return "<wrapped address>"; /* Reject if NULL or ZERO-allocation. */ @@ -134,31 +134,16 @@ static inline const char *check_bogus_address(const void *ptr, unsigned long n) return NULL; } -static inline const char *check_heap_object(const void *ptr, unsigned long n, - bool to_user) +/* Checks for allocs that are marked in some way as spanning multiple pages. */ +static inline const char *check_page_span(const void *ptr, unsigned long n, + struct page *page, bool to_user) { - struct page *page, *endpage; +#ifdef CONFIG_HARDENED_USERCOPY_PAGESPAN const void *end = ptr + n - 1; + struct page *endpage; bool is_reserved, is_cma; /* - * Some architectures (arm64) return true for virt_addr_valid() on - * vmalloced addresses. Work around this by checking for vmalloc - * first. - */ - if (is_vmalloc_addr(ptr)) - return NULL; - - if (!virt_addr_valid(ptr)) - return NULL; - - page = virt_to_head_page(ptr); - - /* Check slab allocator for flags and size. */ - if (PageSlab(page)) - return __check_heap_object(ptr, n, page); - - /* * Sometimes the kernel data regions are not marked Reserved (see * check below). And sometimes [_sdata,_edata) does not cover * rodata and/or bss, so check each range explicitly. @@ -186,7 +171,7 @@ static inline const char *check_heap_object(const void *ptr, unsigned long n, ((unsigned long)end & (unsigned long)PAGE_MASK))) return NULL; - /* Allow if start and end are inside the same compound page. */ + /* Allow if fully inside the same compound (__GFP_COMP) page. */ endpage = virt_to_head_page(end); if (likely(endpage == page)) return NULL; @@ -199,20 +184,44 @@ static inline const char *check_heap_object(const void *ptr, unsigned long n, is_reserved = PageReserved(page); is_cma = is_migrate_cma_page(page); if (!is_reserved && !is_cma) - goto reject; + return "<spans multiple pages>"; for (ptr += PAGE_SIZE; ptr <= end; ptr += PAGE_SIZE) { page = virt_to_head_page(ptr); if (is_reserved && !PageReserved(page)) - goto reject; + return "<spans Reserved and non-Reserved pages>"; if (is_cma && !is_migrate_cma_page(page)) - goto reject; + return "<spans CMA and non-CMA pages>"; } +#endif return NULL; +} + +static inline const char *check_heap_object(const void *ptr, unsigned long n, + bool to_user) +{ + struct page *page; + + /* + * Some architectures (arm64) return true for virt_addr_valid() on + * vmalloced addresses. Work around this by checking for vmalloc + * first. + */ + if (is_vmalloc_addr(ptr)) + return NULL; + + if (!virt_addr_valid(ptr)) + return NULL; + + page = virt_to_head_page(ptr); + + /* Check slab allocator for flags and size. */ + if (PageSlab(page)) + return __check_heap_object(ptr, n, page); -reject: - return "<spans multiple pages>"; + /* Verify object does not incorrectly span multiple pages. */ + return check_page_span(ptr, n, page, to_user); } /* |