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[lisa] Make go_marshal pass correctly sized buffers to safecopy.

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gohacks.Memmove() takes in the number of bytes to move. The current generated
code passes len(src) and len(dst) as the number of bytes to move.

However, the marshal.Marshallable interface allows passing in larger buffers.
The stated precondition is that the buffer should be "at least" SizeBytes()
in length but it is allowed to be larger.

This change now correctly calls Memmove with the argument for the number of
bytes to move as type.SizeBytes(). This was caught when I made lisafs use the
Unsafe marshalling API and got a lot of memory violations.

PiperOrigin-RevId: 368952642
This commit is contained in:
Ayush Ranjan
2021-04-16 17:51:52 -07:00
committed by gVisor bot
parent 32c18f443f
commit ee45334f14
3 changed files with 8 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tools/go_marshal/gomarshal/generator_interfaces_array_newtype.go
+2 -2
View File
@@ -89,14 +89,14 @@ func (g *interfaceGenerator) emitMarshallableForArrayNewtype(n *ast.Ident, a *as
g.emit("// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.\n")
g.emit("func (%s *%s) MarshalUnsafe(dst []byte) {\n", g.r, g.typeName())
g.inIndent(func() {
g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(&%s[0]), uintptr(len(dst)))\n", g.r)
g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(&%s[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
})
g.emit("}\n\n")
g.emit("// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.\n")
g.emit("func (%s *%s) UnmarshalUnsafe(src []byte) {\n", g.r, g.typeName())
g.inIndent(func() {
g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(len(src)))\n", g.r)
g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
})
g.emit("}\n\n")
tools/go_marshal/gomarshal/generator_interfaces_primitive_newtype.go
+2 -2
View File
@@ -141,14 +141,14 @@ func (g *interfaceGenerator) emitMarshallableForPrimitiveNewtype(nt *ast.Ident)
g.emit("// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.\n")
g.emit("func (%s *%s) MarshalUnsafe(dst []byte) {\n", g.r, g.typeName())
g.inIndent(func() {
g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s), uintptr(len(dst)))\n", g.r)
g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s), uintptr(%s.SizeBytes()))\n", g.r, g.r)
})
g.emit("}\n\n")
g.emit("// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.\n")
g.emit("func (%s *%s) UnmarshalUnsafe(src []byte) {\n", g.r, g.typeName())
g.inIndent(func() {
g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(len(src)))\n", g.r)
g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
})
g.emit("}\n\n")
tools/go_marshal/gomarshal/generator_interfaces_struct.go
+4 -4
View File
@@ -275,13 +275,13 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) {
if cond, ok := g.areFieldsPackedExpression(); ok {
g.emit("if %s {\n", cond)
g.inIndent(func() {
g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s), uintptr(len(dst)))\n", g.r)
g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s), uintptr(%s.SizeBytes()))\n", g.r, g.r)
})
g.emit("} else {\n")
g.inIndent(fallback)
g.emit("}\n")
} else {
g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s), uintptr(len(dst)))\n", g.r)
g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s), uintptr(%s.SizeBytes()))\n", g.r, g.r)
}
} else {
fallback()
@@ -301,13 +301,13 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) {
if cond, ok := g.areFieldsPackedExpression(); ok {
g.emit("if %s {\n", cond)
g.inIndent(func() {
g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(len(src)))\n", g.r)
g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
})
g.emit("} else {\n")
g.inIndent(fallback)
g.emit("}\n")
} else {
g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(len(src)))\n", g.r)
g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
}
} else {
fallback()