diff options
| author | Chen Jie <chenjie6@huawei.com> | 2019-03-15 03:44:38 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-27 14:13:03 +0900 |
| commit | 726c28f30ac16e0d4cab17751b447e4abf61b102 (patch) | |
| tree | 746eafbe944aecec1cc9c3bf0af9a12b2f2570be | |
| parent | b84089b2b7939fddc5fcad27511bfa1fa4d760b7 (diff) | |
futex: Ensure that futex address is aligned in handle_futex_death()
commit 5a07168d8d89b00fe1760120714378175b3ef992 upstream.
The futex code requires that the user space addresses of futexes are 32bit
aligned. sys_futex() checks this in futex_get_keys() but the robust list
code has no alignment check in place.
As a consequence the kernel crashes on architectures with strict alignment
requirements in handle_futex_death() when trying to cmpxchg() on an
unaligned futex address which was retrieved from the robust list.
[ tglx: Rewrote changelog, proper sizeof() based alignement check and add
comment ]
Fixes: 0771dfefc9e5 ("[PATCH] lightweight robust futexes: core")
Signed-off-by: Chen Jie <chenjie6@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <dvhart@infradead.org>
Cc: <peterz@infradead.org>
Cc: <zengweilin@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1552621478-119787-1-git-send-email-chenjie6@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/futex.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 30fe0432c46d..2e766ffff2cb 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -3110,6 +3110,10 @@ int handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi) { u32 uval, uninitialized_var(nval), mval; + /* Futex address must be 32bit aligned */ + if ((((unsigned long)uaddr) % sizeof(*uaddr)) != 0) + return -1; + retry: if (get_user(uval, uaddr)) return -1; |