When running a 64-bit kernel and receiving prctls from a 32-bit
userspace, the "-1" used as an unsigned long will end up being
misdetected. The kernel is looking for 0xffffffffffffffff instead of
0xffffffff. Since prctl lacks a distinct compat interface, Yama needs
to handle this translation itself. As such, support either value as
meaning PR_SET_PTRACER_ANY, to avoid breaking the ABI for 64-bit.
Signed-off-by: Kees Cook <keesc...@chromium.org>
Cc: sta...@vger.kernel.org
---
security/yama/yama_lsm.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c
index 0cc99a3..dcd6178 100644
--- a/security/yama/yama_lsm.c
+++ b/security/yama/yama_lsm.c
@@ -143,7 +143,7 @@ static int yama_task_prctl(int option, unsigned long arg2,
unsigned long arg3,
if (arg2 == 0) {
yama_ptracer_del(NULL, myself);
rc = 0;
- } else if (arg2 == PR_SET_PTRACER_ANY) {
+ } else if (arg2 == PR_SET_PTRACER_ANY || (int)arg2 == -1) {
rc = yama_ptracer_add(NULL, myself);
} else {
struct task_struct *tracer;
--
1.7.0.4
--
Kees Cook
Chrome OS Security
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