From 79fecc2b7506f29fb91becc65e8788e5ae7eba9f Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 23 Sep 2017 14:59:54 +0200 Subject: [PATCH] x86/fpu: Split copy_user_to_xstate() into copy_kernel_to_xstate() & copy_user_to_xstate() Similar to: x86/fpu: Split copy_xstate_to_user() into copy_xstate_to_kernel() & copy_xstate_to_user() No change in functionality. Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Eric Biggers Cc: Fenghua Yu Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Yu-cheng Yu Link: http://lkml.kernel.org/r/20170923130016.21448-12-mingo@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/fpu/xstate.h | 4 +- arch/x86/kernel/fpu/regset.c | 10 +++-- arch/x86/kernel/fpu/xstate.c | 66 ++++++++++++++++++++++++++++++- 3 files changed, 74 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index fed6617a1079..79af79dbcab6 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -50,6 +50,6 @@ const void *get_xsave_field_ptr(int xstate_field); int using_compacted_format(void); int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size); int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size); -int copy_user_to_xstate(const void *kbuf, const void __user *ubuf, - struct xregs_state *xsave); +int copy_kernel_to_xstate(const void *kbuf, const void __user *ubuf, struct xregs_state *xsave); +int copy_user_to_xstate(const void *kbuf, const void __user *ubuf, struct xregs_state *xsave); #endif diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c index ec1404194b65..cb45dd81d617 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -134,10 +134,14 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, fpu__activate_fpstate_write(fpu); - if (boot_cpu_has(X86_FEATURE_XSAVES)) - ret = copy_user_to_xstate(kbuf, ubuf, xsave); - else + if (boot_cpu_has(X86_FEATURE_XSAVES)) { + if (kbuf) + ret = copy_kernel_to_xstate(kbuf, ubuf, xsave); + else + ret = copy_user_to_xstate(kbuf, ubuf, xsave); + } else { ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1); + } /* * In case of failure, mark all states as init: diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 00c3b41c3cf1..1ad25d1b8056 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1084,7 +1084,71 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i } /* - * Convert from a ptrace standard-format buffer to kernel XSAVES format + * Convert from a ptrace standard-format kernel buffer to kernel XSAVES format + * and copy to the target thread. This is called from xstateregs_set() and + * there we check the CPU has XSAVES and a whole standard-sized buffer + * exists. + */ +int copy_kernel_to_xstate(const void *kbuf, const void __user *ubuf, + struct xregs_state *xsave) +{ + unsigned int offset, size; + int i; + u64 xfeatures; + u64 allowed_features; + + offset = offsetof(struct xregs_state, header); + size = sizeof(xfeatures); + + if (kbuf) { + memcpy(&xfeatures, kbuf + offset, size); + } else { + if (__copy_from_user(&xfeatures, ubuf + offset, size)) + return -EFAULT; + } + + /* + * Reject if the user sets any disabled or supervisor features: + */ + allowed_features = xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR; + + if (xfeatures & ~allowed_features) + return -EINVAL; + + for (i = 0; i < XFEATURE_MAX; i++) { + u64 mask = ((u64)1 << i); + + if (xfeatures & mask) { + void *dst = __raw_xsave_addr(xsave, 1 << i); + + offset = xstate_offsets[i]; + size = xstate_sizes[i]; + + if (kbuf) { + memcpy(dst, kbuf + offset, size); + } else { + if (__copy_from_user(dst, ubuf + offset, size)) + return -EFAULT; + } + } + } + + /* + * The state that came in from userspace was user-state only. + * Mask all the user states out of 'xfeatures': + */ + xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR; + + /* + * Add back in the features that came in from userspace: + */ + xsave->header.xfeatures |= xfeatures; + + return 0; +} + +/* + * Convert from a ptrace standard-format user-space buffer to kernel XSAVES format * and copy to the target thread. This is called from xstateregs_set() and * there we check the CPU has XSAVES and a whole standard-sized buffer * exists. -- 2.20.1