diff options
| author | Eric Biggers <ebiggers@google.com> | 2017-09-24 12:59:06 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-09-26 09:43:46 +0200 |
| commit | b11e2e18a7fc8eaa3d592c260d50c7129e094ded (patch) | |
| tree | adb2758edce73498589898e57dc694483077b3b8 | |
| parent | cf9df81b139b6ebaec188d73758f02ca3b2110e4 (diff) | |
| download | linux-b11e2e18a7fc8eaa3d592c260d50c7129e094ded.tar.bz2 | |
x86/fpu: Use validate_xstate_header() to validate the xstate_header in __fpu__restore_sig()
Tighten the checks in __fpu__restore_sig() and update comments.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kevin Hao <haokexin@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Halcrow <mhalcrow@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: kernel-hardening@lists.openwall.com
Link: http://lkml.kernel.org/r/20170924105913.9157-4-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/kernel/fpu/signal.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 7fa3bdb331e9..fb639e70048f 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -214,8 +214,11 @@ sanitize_restored_xstate(struct task_struct *tsk, struct xstate_header *header = &xsave->header; if (use_xsave()) { - /* These bits must be zero. */ - memset(header->reserved, 0, 48); + /* + * Note: we don't need to zero the reserved bits in the + * xstate_header here because we either didn't copy them at all, + * or we checked earlier that they aren't set. + */ /* * Init the state that is not present in the memory @@ -224,7 +227,7 @@ sanitize_restored_xstate(struct task_struct *tsk, if (fx_only) header->xfeatures = XFEATURE_MASK_FPSSE; else - header->xfeatures &= (xfeatures_mask & xfeatures); + header->xfeatures &= xfeatures; } if (use_fxsr()) { @@ -308,7 +311,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) /* * For 32-bit frames with fxstate, copy the user state to the * thread's fpu state, reconstruct fxstate from the fsave - * header. Sanitize the copied state etc. + * header. Validate and sanitize the copied state. */ struct fpu *fpu = &tsk->thread.fpu; struct user_i387_ia32_struct env; @@ -329,9 +332,8 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) } else { err = __copy_from_user(&fpu->state.xsave, buf_fx, state_size); - /* xcomp_bv must be 0 when using uncompacted format */ - if (!err && state_size > offsetof(struct xregs_state, header) && fpu->state.xsave.header.xcomp_bv) - err = -EINVAL; + if (!err && state_size > offsetof(struct xregs_state, header)) + err = validate_xstate_header(&fpu->state.xsave.header); } if (err || __copy_from_user(&env, buf, sizeof(env))) { |