diff options
| author |   Thomas Gleixner <tglx@linutronix.de> | 2021-09-08 15:29:30 +0200 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2021-09-14 21:10:03 +0200 |
| commit | fcfb7163329ce832aafef31f26345ef5e8642a17 (patch) | |
| tree | de788ae378a3a9a4df8b876ed82201f5784b4fab /arch/x86/kernel | |
| parent | x86/fpu/signal: Move header zeroing out of xsave_to_user_sigframe() (diff) | |
| download | linux-dev-fcfb7163329ce832aafef31f26345ef5e8642a17.tar.xz linux-dev-fcfb7163329ce832aafef31f26345ef5e8642a17.zip | |
x86/fpu/signal: Move xstate clearing out of copy_fpregs_to_sigframe()
When the direct saving of the FPU registers to the user space sigframe
fails, copy_fpregs_to_sigframe() attempts to clear the user buffer.
The most likely reason for such a fail is a page fault. As
copy_fpregs_to_sigframe() is invoked with pagefaults disabled the chance
that __clear_user() succeeds is minuscule.
Move the clearing out into the caller which replaces the
fault_in_pages_writeable() in that error handling path.
The return value confusion will be cleaned up separately.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210908132525.679356300@linutronix.de
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/fpu/signal.c | 18 |
1 files changed, 6 insertions, 12 deletions
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 5ca3ce94cf6b..c4abbd97587b 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -136,18 +136,12 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame) static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) { - int err; - if (use_xsave()) - err = xsave_to_user_sigframe(buf); - else if (use_fxsr()) - err = fxsave_to_user_sigframe((struct fxregs_state __user *) buf); + return xsave_to_user_sigframe(buf); + if (use_fxsr()) + return fxsave_to_user_sigframe((struct fxregs_state __user *) buf); else - err = fnsave_to_user_sigframe((struct fregs_state __user *) buf); - - if (unlikely(err) && __clear_user(buf, fpu_user_xstate_size)) - err = -EFAULT; - return err; + return fnsave_to_user_sigframe((struct fregs_state __user *) buf); } /* @@ -218,9 +212,9 @@ retry: fpregs_unlock(); if (ret) { - if (!fault_in_pages_writeable(buf_fx, fpu_user_xstate_size)) + if (!__clear_user(buf_fx, fpu_user_xstate_size)) goto retry; - return -EFAULT; + return -1; } /* Save the fsave header for the 32-bit frames. */ |