diff options
Diffstat (limited to 'src/runtime/checkptr.go')
| -rw-r--r-- | src/runtime/checkptr.go | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/src/runtime/checkptr.go b/src/runtime/checkptr.go index d42950844b..2d4afd5cf6 100644 --- a/src/runtime/checkptr.go +++ b/src/runtime/checkptr.go @@ -7,6 +7,11 @@ package runtime import "unsafe" func checkptrAlignment(p unsafe.Pointer, elem *_type, n uintptr) { + // nil pointer is always suitably aligned (#47430). + if p == nil { + return + } + // Check that (*[n]elem)(p) is appropriately aligned. // Note that we allow unaligned pointers if the types they point to contain // no pointers themselves. See issue 37298. @@ -29,10 +34,12 @@ func checkptrStraddles(ptr unsafe.Pointer, size uintptr) bool { return false } - end := add(ptr, size-1) - if uintptr(end) < uintptr(ptr) { + // Check that add(ptr, size-1) won't overflow. This avoids the risk + // of producing an illegal pointer value (assuming ptr is legal). + if uintptr(ptr) >= -(size - 1) { return true } + end := add(ptr, size-1) // TODO(mdempsky): Detect when [ptr, end] contains Go allocations, // but neither ptr nor end point into one themselves. |