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authorGuillermo Julián Moreno <guillermo.julian@naudit.es>2016-06-03 14:55:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-06-03 15:06:22 -0700
commit65ee03c4b9f89e1b088defd97273be6da169d798 (patch)
treeca5bd05b3bc29cf2a5a07f083fd80221049aa06e
parent4340fa55298d17049e71c7a34e04647379c269f3 (diff)
downloadlinux-65ee03c4b9f89e1b088defd97273be6da169d798.tar.gz
mm: fix overflow in vm_map_ram()
When remapping pages accounting for 4G or more memory space, the operation 'count << PAGE_SHIFT' overflows as it is performed on an integer. Solution: cast before doing the bitshift. [akpm@linux-foundation.org: fix vm_unmap_ram() also] [akpm@linux-foundation.org: fix vmap() as well, per Guillermo] Link: http://lkml.kernel.org/r/etPan.57175fb3.7a271c6b.2bd@naudit.es Signed-off-by: Guillermo Julián Moreno <guillermo.julian@naudit.es> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/vmalloc.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index cf7ad1a53be0..e11475cdeb7a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1105,7 +1105,7 @@ EXPORT_SYMBOL_GPL(vm_unmap_aliases);
*/
void vm_unmap_ram(const void *mem, unsigned int count)
{
- unsigned long size = count << PAGE_SHIFT;
+ unsigned long size = (unsigned long)count << PAGE_SHIFT;
unsigned long addr = (unsigned long)mem;
BUG_ON(!addr);
@@ -1140,7 +1140,7 @@ EXPORT_SYMBOL(vm_unmap_ram);
*/
void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
{
- unsigned long size = count << PAGE_SHIFT;
+ unsigned long size = (unsigned long)count << PAGE_SHIFT;
unsigned long addr;
void *mem;
@@ -1574,14 +1574,15 @@ void *vmap(struct page **pages, unsigned int count,
unsigned long flags, pgprot_t prot)
{
struct vm_struct *area;
+ unsigned long size; /* In bytes */
might_sleep();
if (count > totalram_pages)
return NULL;
- area = get_vm_area_caller((count << PAGE_SHIFT), flags,
- __builtin_return_address(0));
+ size = (unsigned long)count << PAGE_SHIFT;
+ area = get_vm_area_caller(size, flags, __builtin_return_address(0));
if (!area)
return NULL;