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Subject[GIT pull] x86/urgent for
Linus,

please pull the latest x86/urgent branch from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-urgent-2020-05-31

up to: aa61b7bb00f7: Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs into x86/urgent


A pile of x86 fixes:

- Prevent a memory leak in ioperm which was caused by the stupid
assumption that the exit cleanup is always called for current, which is
not the case when fork fails after taking a reference on the ioperm
bitmap.

- Fix an arithmething overflow in the DMA code on 32bit systems

- Fill gaps in the xstate copy with defaults instead of leaving them
uninitialized

- Revert: "Make __X32_SYSCALL_BIT be unsigned long" as it turned out
that existing user space fails to build.

Thanks,

tglx

------------------>
Al Viro (1):
copy_xstate_to_kernel(): don't leave parts of destination uninitialized

Alexander Dahl (1):
x86/dma: Fix max PFN arithmetic overflow on 32 bit systems

Andy Lutomirski (1):
x86/syscalls: Revert "x86/syscalls: Make __X32_SYSCALL_BIT be unsigned long"

Jay Lang (1):
x86/ioperm: Prevent a memory leak when fork fails


arch/x86/include/asm/dma.h | 2 +-
arch/x86/include/asm/io_bitmap.h | 4 +-
arch/x86/include/uapi/asm/unistd.h | 11 +++-
arch/x86/kernel/fpu/xstate.c | 86 ++++++++++++++++++--------------
arch/x86/kernel/ioport.c | 22 ++++----
arch/x86/kernel/process.c | 4 +-
tools/arch/x86/include/uapi/asm/unistd.h | 2 +-
7 files changed, 74 insertions(+), 57 deletions(-)

diff --git a/arch/x86/include/asm/dma.h b/arch/x86/include/asm/dma.h
index 00f7cf45e699..8e95aa4b0d17 100644
--- a/arch/x86/include/asm/dma.h
+++ b/arch/x86/include/asm/dma.h
@@ -74,7 +74,7 @@
#define MAX_DMA_PFN ((16UL * 1024 * 1024) >> PAGE_SHIFT)

/* 4GB broken PCI/AGP hardware bus master zone */
-#define MAX_DMA32_PFN ((4UL * 1024 * 1024 * 1024) >> PAGE_SHIFT)
+#define MAX_DMA32_PFN (1UL << (32 - PAGE_SHIFT))

#ifdef CONFIG_X86_32
/* The maximum address that we can perform a DMA transfer to on this platform */
diff --git a/arch/x86/include/asm/io_bitmap.h b/arch/x86/include/asm/io_bitmap.h
index 07344d82e88e..ac1a99ffbd8d 100644
--- a/arch/x86/include/asm/io_bitmap.h
+++ b/arch/x86/include/asm/io_bitmap.h
@@ -17,7 +17,7 @@ struct task_struct;

#ifdef CONFIG_X86_IOPL_IOPERM
void io_bitmap_share(struct task_struct *tsk);
-void io_bitmap_exit(void);
+void io_bitmap_exit(struct task_struct *tsk);

void native_tss_update_io_bitmap(void);

@@ -29,7 +29,7 @@ void native_tss_update_io_bitmap(void);

#else
static inline void io_bitmap_share(struct task_struct *tsk) { }
-static inline void io_bitmap_exit(void) { }
+static inline void io_bitmap_exit(struct task_struct *tsk) { }
static inline void tss_update_io_bitmap(void) { }
#endif

diff --git a/arch/x86/include/uapi/asm/unistd.h b/arch/x86/include/uapi/asm/unistd.h
index 196fdd02b8b1..be5e2e747f50 100644
--- a/arch/x86/include/uapi/asm/unistd.h
+++ b/arch/x86/include/uapi/asm/unistd.h
@@ -2,8 +2,15 @@
#ifndef _UAPI_ASM_X86_UNISTD_H
#define _UAPI_ASM_X86_UNISTD_H

-/* x32 syscall flag bit */
-#define __X32_SYSCALL_BIT 0x40000000UL
+/*
+ * x32 syscall flag bit. Some user programs expect syscall NR macros
+ * and __X32_SYSCALL_BIT to have type int, even though syscall numbers
+ * are, for practical purposes, unsigned long.
+ *
+ * Fortunately, expressions like (nr & ~__X32_SYSCALL_BIT) do the right
+ * thing regardless.
+ */
+#define __X32_SYSCALL_BIT 0x40000000

#ifndef __KERNEL__
# ifdef __i386__
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 32b153d38748..6a54e83d5589 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -957,18 +957,31 @@ static inline bool xfeatures_mxcsr_quirk(u64 xfeatures)
return true;
}

-/*
- * This is similar to user_regset_copyout(), but will not add offset to
- * the source data pointer or increment pos, count, kbuf, and ubuf.
- */
-static inline void
-__copy_xstate_to_kernel(void *kbuf, const void *data,
- unsigned int offset, unsigned int size, unsigned int size_total)
+static void fill_gap(unsigned to, void **kbuf, unsigned *pos, unsigned *count)
{
- if (offset < size_total) {
- unsigned int copy = min(size, size_total - offset);
+ if (*pos < to) {
+ unsigned size = to - *pos;
+
+ if (size > *count)
+ size = *count;
+ memcpy(*kbuf, (void *)&init_fpstate.xsave + *pos, size);
+ *kbuf += size;
+ *pos += size;
+ *count -= size;
+ }
+}

- memcpy(kbuf + offset, data, copy);
+static void copy_part(unsigned offset, unsigned size, void *from,
+ void **kbuf, unsigned *pos, unsigned *count)
+{
+ fill_gap(offset, kbuf, pos, count);
+ if (size > *count)
+ size = *count;
+ if (size) {
+ memcpy(*kbuf, from, size);
+ *kbuf += size;
+ *pos += size;
+ *count -= size;
}
}

@@ -981,8 +994,9 @@ __copy_xstate_to_kernel(void *kbuf, const void *data,
*/
int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset_start, unsigned int size_total)
{
- unsigned int offset, size;
struct xstate_header header;
+ const unsigned off_mxcsr = offsetof(struct fxregs_state, mxcsr);
+ unsigned count = size_total;
int i;

/*
@@ -998,46 +1012,42 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int of
header.xfeatures = xsave->header.xfeatures;
header.xfeatures &= ~XFEATURE_MASK_SUPERVISOR;

+ if (header.xfeatures & XFEATURE_MASK_FP)
+ copy_part(0, off_mxcsr,
+ &xsave->i387, &kbuf, &offset_start, &count);
+ if (header.xfeatures & (XFEATURE_MASK_SSE | XFEATURE_MASK_YMM))
+ copy_part(off_mxcsr, MXCSR_AND_FLAGS_SIZE,
+ &xsave->i387.mxcsr, &kbuf, &offset_start, &count);
+ if (header.xfeatures & XFEATURE_MASK_FP)
+ copy_part(offsetof(struct fxregs_state, st_space), 128,
+ &xsave->i387.st_space, &kbuf, &offset_start, &count);
+ if (header.xfeatures & XFEATURE_MASK_SSE)
+ copy_part(xstate_offsets[XFEATURE_MASK_SSE], 256,
+ &xsave->i387.xmm_space, &kbuf, &offset_start, &count);
+ /*
+ * Fill xsave->i387.sw_reserved value for ptrace frame:
+ */
+ copy_part(offsetof(struct fxregs_state, sw_reserved), 48,
+ xstate_fx_sw_bytes, &kbuf, &offset_start, &count);
/*
* Copy xregs_state->header:
*/
- offset = offsetof(struct xregs_state, header);
- size = sizeof(header);
-
- __copy_xstate_to_kernel(kbuf, &header, offset, size, size_total);
+ copy_part(offsetof(struct xregs_state, header), sizeof(header),
+ &header, &kbuf, &offset_start, &count);

- for (i = 0; i < XFEATURE_MAX; i++) {
+ for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
/*
* Copy only in-use xstates:
*/
if ((header.xfeatures >> i) & 1) {
void *src = __raw_xsave_addr(xsave, i);

- offset = xstate_offsets[i];
- size = xstate_sizes[i];
-
- /* The next component has to fit fully into the output buffer: */
- if (offset + size > size_total)
- break;
-
- __copy_xstate_to_kernel(kbuf, src, offset, size, size_total);
+ copy_part(xstate_offsets[i], xstate_sizes[i],
+ src, &kbuf, &offset_start, &count);
}

}
-
- if (xfeatures_mxcsr_quirk(header.xfeatures)) {
- offset = offsetof(struct fxregs_state, mxcsr);
- size = MXCSR_AND_FLAGS_SIZE;
- __copy_xstate_to_kernel(kbuf, &xsave->i387.mxcsr, offset, size, size_total);
- }
-
- /*
- * Fill xsave->i387.sw_reserved value for ptrace frame:
- */
- offset = offsetof(struct fxregs_state, sw_reserved);
- size = sizeof(xstate_fx_sw_bytes);
-
- __copy_xstate_to_kernel(kbuf, xstate_fx_sw_bytes, offset, size, size_total);
+ fill_gap(size_total, &kbuf, &offset_start, &count);

return 0;
}
diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index a53e7b4a7419..e2fab3ceb09f 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -33,15 +33,15 @@ void io_bitmap_share(struct task_struct *tsk)
set_tsk_thread_flag(tsk, TIF_IO_BITMAP);
}

-static void task_update_io_bitmap(void)
+static void task_update_io_bitmap(struct task_struct *tsk)
{
- struct thread_struct *t = &current->thread;
+ struct thread_struct *t = &tsk->thread;

if (t->iopl_emul == 3 || t->io_bitmap) {
/* TSS update is handled on exit to user space */
- set_thread_flag(TIF_IO_BITMAP);
+ set_tsk_thread_flag(tsk, TIF_IO_BITMAP);
} else {
- clear_thread_flag(TIF_IO_BITMAP);
+ clear_tsk_thread_flag(tsk, TIF_IO_BITMAP);
/* Invalidate TSS */
preempt_disable();
tss_update_io_bitmap();
@@ -49,12 +49,12 @@ static void task_update_io_bitmap(void)
}
}

-void io_bitmap_exit(void)
+void io_bitmap_exit(struct task_struct *tsk)
{
- struct io_bitmap *iobm = current->thread.io_bitmap;
+ struct io_bitmap *iobm = tsk->thread.io_bitmap;

- current->thread.io_bitmap = NULL;
- task_update_io_bitmap();
+ tsk->thread.io_bitmap = NULL;
+ task_update_io_bitmap(tsk);
if (iobm && refcount_dec_and_test(&iobm->refcnt))
kfree(iobm);
}
@@ -102,7 +102,7 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
if (!iobm)
return -ENOMEM;
refcount_set(&iobm->refcnt, 1);
- io_bitmap_exit();
+ io_bitmap_exit(current);
}

/*
@@ -134,7 +134,7 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
}
/* All permissions dropped? */
if (max_long == UINT_MAX) {
- io_bitmap_exit();
+ io_bitmap_exit(current);
return 0;
}

@@ -192,7 +192,7 @@ SYSCALL_DEFINE1(iopl, unsigned int, level)
}

t->iopl_emul = level;
- task_update_io_bitmap();
+ task_update_io_bitmap(current);

return 0;
}
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 9da70b279dad..35638f1c5791 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -96,7 +96,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
}

/*
- * Free current thread data structures etc..
+ * Free thread data structures etc..
*/
void exit_thread(struct task_struct *tsk)
{
@@ -104,7 +104,7 @@ void exit_thread(struct task_struct *tsk)
struct fpu *fpu = &t->fpu;

if (test_thread_flag(TIF_IO_BITMAP))
- io_bitmap_exit();
+ io_bitmap_exit(tsk);

free_vm86(t);

diff --git a/tools/arch/x86/include/uapi/asm/unistd.h b/tools/arch/x86/include/uapi/asm/unistd.h
index 196fdd02b8b1..30d7d04d72d6 100644
--- a/tools/arch/x86/include/uapi/asm/unistd.h
+++ b/tools/arch/x86/include/uapi/asm/unistd.h
@@ -3,7 +3,7 @@
#define _UAPI_ASM_X86_UNISTD_H

/* x32 syscall flag bit */
-#define __X32_SYSCALL_BIT 0x40000000UL
+#define __X32_SYSCALL_BIT 0x40000000

#ifndef __KERNEL__
# ifdef __i386__
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