[tip:core/locking] futex: Mark get_robust_list as deprecated

From: tip-bot for Kees Cook
Date: Thu Mar 29 2012 - 05:57:23 EST

Commit-ID: ec0c4274e33c0373e476b73e01995c53128f1257
Gitweb: http://git.kernel.org/tip/ec0c4274e33c0373e476b73e01995c53128f1257
Author: Kees Cook <keescook@xxxxxxxxxxxx>
AuthorDate: Fri, 23 Mar 2012 12:08:55 -0700
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 29 Mar 2012 11:37:17 +0200

futex: Mark get_robust_list as deprecated

Notify get_robust_list users that the syscall is going away.

Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxx>
Cc: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Serge E. Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Cc: kernel-hardening@xxxxxxxxxxxxxxxxxx
Cc: spender@xxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20120323190855.GA27213@xxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Documentation/feature-removal-schedule.txt | 10 ++++++++++
kernel/futex.c | 2 ++
kernel/futex_compat.c | 2 ++
3 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 0cad480..c1be806 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -529,3 +529,13 @@ When: 3.5
Why: The old kmap_atomic() with two arguments is deprecated, we only
keep it for backward compatibility for few cycles and then drop it.
Who: Cong Wang <amwang@xxxxxxxxxx>
+What: get_robust_list syscall
+When: 2013
+Why: There appear to be no production users of the get_robust_list syscall,
+ and it runs the risk of leaking address locations, allowing the bypass
+ of ASLR. It was only ever intended for debugging, so it should be
+ removed.
+Who: Kees Cook <keescook@xxxxxxxxxxxx>
diff --git a/kernel/futex.c b/kernel/futex.c
index d701be5..e2b0fb9 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2449,6 +2449,8 @@ SYSCALL_DEFINE3(get_robust_list, int, pid,
if (!futex_cmpxchg_enabled)
return -ENOSYS;

+ WARN_ONCE(1, "deprecated: get_robust_list will be deleted in 2013.\n");

ret = -ESRCH;
diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
index a9642d5..83e368b 100644
--- a/kernel/futex_compat.c
+++ b/kernel/futex_compat.c
@@ -142,6 +142,8 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
if (!futex_cmpxchg_enabled)
return -ENOSYS;

+ WARN_ONCE(1, "deprecated: get_robust_list will be deleted in 2013.\n");

ret = -ESRCH;
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