Merge tag 'meminit-v5.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees...
authorLinus Torvalds <torvalds@linux-foundation.org>
Sun, 28 Jul 2019 19:33:15 +0000 (12:33 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sun, 28 Jul 2019 19:33:15 +0000 (12:33 -0700)
Pull structleak fix from Kees Cook:
 "Disable gcc-based stack variable auto-init under KASAN (Arnd
  Bergmann).

  This fixes a bunch of build warnings under KASAN and the
  gcc-plugin-based stack auto-initialization features (which are
  arguably redundant, so better to let KASAN control this)"

* tag 'meminit-v5.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  structleak: disable STRUCTLEAK_BYREF in combination with KASAN_STACK

security/Kconfig.hardening

index a1ffe2e..af4c979 100644 (file)
@@ -61,6 +61,7 @@ choice
        config GCC_PLUGIN_STRUCTLEAK_BYREF
                bool "zero-init structs passed by reference (strong)"
                depends on GCC_PLUGINS
+               depends on !(KASAN && KASAN_STACK=1)
                select GCC_PLUGIN_STRUCTLEAK
                help
                  Zero-initialize any structures on the stack that may
@@ -70,9 +71,15 @@ choice
                  exposures, like CVE-2017-1000410:
                  https://git.kernel.org/linus/06e7e776ca4d3654
 
+                 As a side-effect, this keeps a lot of variables on the
+                 stack that can otherwise be optimized out, so combining
+                 this with CONFIG_KASAN_STACK can lead to a stack overflow
+                 and is disallowed.
+
        config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
                bool "zero-init anything passed by reference (very strong)"
                depends on GCC_PLUGINS
+               depends on !(KASAN && KASAN_STACK=1)
                select GCC_PLUGIN_STRUCTLEAK
                help
                  Zero-initialize any stack variables that may be passed