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x86/fpu: Deduplicate copy_uabi_from_user/kernel_to_xstate()

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copy_uabi_from_user_to_xstate() and copy_uabi_from_kernel_to_xstate() are
almost identical except for the copy function.

Unify them.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20210623121454.414215896@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-06-23 14:01:58 +02:00 committed by Borislav Petkov
parent 1cc34413ff
commit 522e92743b
1 changed files with 47 additions and 90 deletions
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137
arch/x86/kernel/fpu/xstate.c
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@ -953,23 +953,6 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
} }
#endif /* ! CONFIG_ARCH_HAS_PKEYS */ #endif /* ! CONFIG_ARCH_HAS_PKEYS */
/*
* Weird legacy quirk: SSE and YMM states store information in the
* MXCSR and MXCSR_FLAGS fields of the FP area. That means if the FP
* area is marked as unused in the xfeatures header, we need to copy
* MXCSR and MXCSR_FLAGS if either SSE or YMM are in use.
*/
static inline bool xfeatures_mxcsr_quirk(u64 xfeatures)
{
if (!(xfeatures & (XFEATURE_MASK_SSE|XFEATURE_MASK_YMM)))
return false;
if (xfeatures & XFEATURE_MASK_FP)
return false;
return true;
}
static void copy_feature(bool from_xstate, struct membuf *to, void *xstate, static void copy_feature(bool from_xstate, struct membuf *to, void *xstate,
void *init_xstate, unsigned int size) void *init_xstate, unsigned int size)
{ {
@ -1082,39 +1065,53 @@ out:
membuf_zero(&to, to.left); membuf_zero(&to, to.left);
} }
static inline bool mxcsr_valid(struct xstate_header *hdr, const u32 *mxcsr) static int copy_from_buffer(void *dst, unsigned int offset, unsigned int size,
const void *kbuf, const void __user *ubuf)
{ {
u64 mask = XFEATURE_MASK_FP | XFEATURE_MASK_SSE | XFEATURE_MASK_YMM; if (kbuf) {
memcpy(dst, kbuf + offset, size);
/* Only check if it is in use */ } else {
if (hdr->xfeatures & mask) { if (copy_from_user(dst, ubuf + offset, size))
/* Reserved bits in MXCSR must be zero. */ return -EFAULT;
if (*mxcsr & ~mxcsr_feature_mask)
return false;
} }
return true; return 0;
} }
/*
* Convert from a ptrace standard-format kernel buffer to kernel XSAVE[S] format static int copy_uabi_to_xstate(struct xregs_state *xsave, const void *kbuf,
* and copy to the target thread. This is called from xstateregs_set(). const void __user *ubuf)
*/
int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
{ {
unsigned int offset, size; unsigned int offset, size;
int i;
struct xstate_header hdr; struct xstate_header hdr;
u64 mask;
int i;
offset = offsetof(struct xregs_state, header); offset = offsetof(struct xregs_state, header);
size = sizeof(hdr); if (copy_from_buffer(&hdr, offset, sizeof(hdr), kbuf, ubuf))
return -EFAULT;
memcpy(&hdr, kbuf + offset, size);
if (validate_user_xstate_header(&hdr)) if (validate_user_xstate_header(&hdr))
return -EINVAL; return -EINVAL;
if (!mxcsr_valid(&hdr, kbuf + offsetof(struct fxregs_state, mxcsr))) /* Validate MXCSR when any of the related features is in use */
return -EINVAL; mask = XFEATURE_MASK_FP | XFEATURE_MASK_SSE | XFEATURE_MASK_YMM;
if (hdr.xfeatures & mask) {
u32 mxcsr[2];
offset = offsetof(struct fxregs_state, mxcsr);
if (copy_from_buffer(mxcsr, offset, sizeof(mxcsr), kbuf, ubuf))
return -EFAULT;
/* Reserved bits in MXCSR must be zero. */
if (mxcsr[0] & ~mxcsr_feature_mask)
return -EINVAL;
/* SSE and YMM require MXCSR even when FP is not in use. */
if (!(hdr.xfeatures & XFEATURE_MASK_FP)) {
xsave->i387.mxcsr = mxcsr[0];
xsave->i387.mxcsr_mask = mxcsr[1];
}
}
for (i = 0; i < XFEATURE_MAX; i++) { for (i = 0; i < XFEATURE_MAX; i++) {
u64 mask = ((u64)1 << i); u64 mask = ((u64)1 << i);
@ -1125,16 +1122,11 @@ int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
offset = xstate_offsets[i]; offset = xstate_offsets[i];
size = xstate_sizes[i]; size = xstate_sizes[i];
memcpy(dst, kbuf + offset, size); if (copy_from_buffer(dst, offset, size, kbuf, ubuf))
return -EFAULT;
} }
} }
if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
offset = offsetof(struct fxregs_state, mxcsr);
size = MXCSR_AND_FLAGS_SIZE;
memcpy(&xsave->i387.mxcsr, kbuf + offset, size);
}
/* /*
* The state that came in from userspace was user-state only. * The state that came in from userspace was user-state only.
* Mask all the user states out of 'xfeatures': * Mask all the user states out of 'xfeatures':
@ -1149,6 +1141,16 @@ int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
return 0; return 0;
} }
/*
* Convert from a ptrace standard-format kernel buffer to kernel XSAVE[S]
* format and copy to the target thread. This is called from
* xstateregs_set().
*/
int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
{
return copy_uabi_to_xstate(xsave, kbuf, NULL);
}
/* /*
* Convert from a sigreturn standard-format user-space buffer to kernel * Convert from a sigreturn standard-format user-space buffer to kernel
* XSAVE[S] format and copy to the target thread. This is called from the * XSAVE[S] format and copy to the target thread. This is called from the
@ -1157,52 +1159,7 @@ int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave, int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave,
const void __user *ubuf) const void __user *ubuf)
{ {
unsigned int offset, size; return copy_uabi_to_xstate(xsave, NULL, ubuf);
int i;
struct xstate_header hdr;
offset = offsetof(struct xregs_state, header);
size = sizeof(hdr);
if (copy_from_user(&hdr, ubuf + offset, size))
return -EFAULT;
if (validate_user_xstate_header(&hdr))
return -EINVAL;
for (i = 0; i < XFEATURE_MAX; i++) {
u64 mask = ((u64)1 << i);
if (hdr.xfeatures & mask) {
void *dst = __raw_xsave_addr(xsave, i);
offset = xstate_offsets[i];
size = xstate_sizes[i];
if (copy_from_user(dst, ubuf + offset, size))
return -EFAULT;
}
}
if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
offset = offsetof(struct fxregs_state, mxcsr);
size = MXCSR_AND_FLAGS_SIZE;
if (copy_from_user(&xsave->i387.mxcsr, 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_ALL;
/*
* Add back in the features that came in from userspace:
*/
xsave->header.xfeatures |= hdr.xfeatures;
return 0;
} }
/** /**