4.18.5-stable review

This is the start of the stable review cycle for the 4.18.5 release. There are 22 patches in this series, all will be posted as a response to this one. If anyone has any issues with these being applied, please let me know.

Responses should be made by Sat Aug 25 07:47:43 UTC 2018. Anything received after that time might be too late.

The whole patch series can be found in one patch at:

	https://www.kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.18.5-rc1.gz

or in the git tree and branch at:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.18.y
and the diffstat can be found below.

thanks,

greg k-h

-------------
Pseudo-Shortlog of commits:

Greg Kroah-Hartman <[email protected]>

    Linux 4.18.5-rc1

Jann Horn <[email protected]>
reiserfs: fix broken xattr handling (heap corruption, bad retval)

Esben Haabendal <[email protected]>
i2c: imx: Fix race condition in dma read

Hans de Goede <[email protected]>
i2c: core: ACPI: Properly set status byte to 0 for multi-byte writes

Lukas Wunner <[email protected]>
PCI: pciehp: Fix unprotected list iteration in IRQ handler

Lukas Wunner <[email protected]>
PCI: pciehp: Fix use-after-free on unplug

Myron Stowe <[email protected]>
PCI: Skip MPS logic for Virtual Functions (VFs)

Zachary Zhang <[email protected]>
PCI: aardvark: Size bridges before resources allocation

Lukas Wunner <[email protected]>
PCI: hotplug: Don't leak pci_slot on registration failure

Rafael J. Wysocki <[email protected]>
PCI / ACPI / PM: Resume all bridges on suspend-to-RAM

Christian König <[email protected]>
PCI: Restore resized BAR state on resume

John David Anglin <[email protected]>
parisc: Remove ordered stores from syscall.S

John David Anglin <[email protected]>
parisc: Remove unnecessary barriers from spinlock.h

Gustavo A. R. Silva <[email protected]>
drm/amdgpu/pm: Fix potential Spectre v1

Gustavo A. R. Silva <[email protected]>
drm/i915/kvmgt: Fix potential Spectre v1

Jeremy Cline <[email protected]>
ext4: fix spectre gadget in ext4_mb_regular_allocator()

Michael Ellerman <[email protected]>
powerpc64s: Show ori31 availability in spectre_v1 sysfs file not v2

Dave Hansen <[email protected]>
x86/mm/init: Remove freed kernel image areas from alias mapping

Dave Hansen <[email protected]>
x86/mm/init: Add helper for freeing kernel image pages

Dave Hansen <[email protected]>
x86/mm/init: Pass unconverted symbol addresses to free_init_pages()

Dave Hansen <[email protected]>
mm: Allow non-direct-map arguments to free_reserved_area()

Matthijs van Duin <[email protected]>
pty: fix O_CLOEXEC for TIOCGPTPEER

Takashi Iwai <[email protected]>

    EDAC: Add missing MEM_LRDDR4 entry in edac_mem_types[]

-------------

Diffstat:

 Makefile                               |  4 ++--
 arch/parisc/include/asm/spinlock.h     |  8 ++------
 arch/parisc/kernel/syscall.S           | 24 +++++++++++-----------
 arch/powerpc/kernel/security.c         | 27 ++++++++++++++++---------
 arch/x86/include/asm/processor.h       |  1 +
 arch/x86/include/asm/set_memory.h      |  1 +
 arch/x86/mm/init.c                     | 37 +++++++++++++++++++++++++++++++---
 arch/x86/mm/init_64.c                  |  8 ++------
 arch/x86/mm/pageattr.c                 | 13 ++++++++++++
 drivers/edac/edac_mc.c                 |  1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c |  3 ++-
 drivers/gpu/drm/i915/gvt/kvmgt.c       |  9 ++++++++-
 drivers/i2c/busses/i2c-imx.c           |  8 ++++----
 drivers/i2c/i2c-core-acpi.c            | 11 +++++++---
 drivers/pci/controller/pci-aardvark.c  |  1 +
 drivers/pci/hotplug/pci_hotplug_core.c |  9 +++++++++
 drivers/pci/hotplug/pciehp.h           |  1 +
 drivers/pci/hotplug/pciehp_core.c      |  7 +++++++
 drivers/pci/hotplug/pciehp_hpc.c       | 18 +++++------------
 drivers/pci/pci-acpi.c                 |  6 ++----
 drivers/pci/pci.c                      | 28 +++++++++++++++++++++++++
 drivers/pci/probe.c                    |  4 ++++
 drivers/tty/pty.c                      |  2 +-
 fs/ext4/mballoc.c                      |  4 +++-
 fs/reiserfs/xattr.c                    |  4 +++-
 mm/page_alloc.c                        | 16 +++++++++++++--
 26 files changed, 185 insertions(+), 70 deletions(-)

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <[email protected]>

commit b748f2de4b2f578599f46c6000683a8da755bf68 upstream.

The edac_mem_types[] array misses a MEM_LRDDR4 entry, which leads to NULL pointer dereference when accessed via sysfs or such.

---
 drivers/edac/edac_mc.c |    1 +
 1 file changed, 1 insertion(+)

@@ -215,6 +215,7 @@ const char * const edac_mem_types[] = {
 	[MEM_LRDDR3]	= "Load-Reduced-DDR3-RAM",
 	[MEM_DDR4]	= "Unbuffered-DDR4",
 	[MEM_RDDR4]	= "Registered-DDR4",
+	[MEM_LRDDR4]	= "Load-Reduced-DDR4-RAM",
 	[MEM_NVDIMM]	= "Non-volatile-RAM",
 };
 EXPORT_SYMBOL_GPL(edac_mem_types);

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Matthijs van Duin <[email protected]>

commit 36ecc1481dc8d8c52d43ba18c6b642c1d2fde789 upstream.

It was being ignored because the flags were not passed to fd allocation.

---
 drivers/tty/pty.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -625,7 +625,7 @@ int ptm_open_peer(struct file *master, s
 	if (tty->driver != ptm_driver)
 		return -EIO;
 
-	fd = get_unused_fd_flags(0);
+	fd = get_unused_fd_flags(flags);
 	if (fd < 0) {
 		retval = fd;
 		goto err;

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dave Hansen <[email protected]>

commit 0d83432811f26871295a9bc24d3c387924da6071 upstream.

free_reserved_area() takes pointers as arguments to show which addresses should be freed. However, it does this in a somewhat ambiguous way. If it gets a kernel direct map address, it always works. However, if it gets an address that is part of the kernel image alias mapping, it can fail.

It fails if all of the following happen:
* The specified address is part of the kernel image alias
* Poisoning is requested (forcing a memset())
* The address is in a read-only portion of the kernel image

The memset() fails on the read-only mapping, of course. free_reserved_area() *is* called both on the direct map and on kernel image alias addresses. We've just lucked out thus far that the kernel image alias areas it gets used on are read-write. I'm fairly sure this has been just a happy accident.

It is quite easy to make free_reserved_area() work for all cases: just convert the address to a direct map address before doing the memset(), and do this unconditionally. There is little chance of a regression here because we previously did a virt_to_page() on the address for the memset, so we know these are not highmem pages for which virt_to_page() would fail.

---
 mm/page_alloc.c |   16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

@@ -6939,9 +6939,21 @@ unsigned long free_reserved_area(void *s
 	start = (void *)PAGE_ALIGN((unsigned long)start);
 	end = (void *)((unsigned long)end & PAGE_MASK);
 	for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
+		struct page *page = virt_to_page(pos);
+		void *direct_map_addr;
+
+		/*
+		 * 'direct_map_addr' might be different from 'pos'
+		 * because some architectures' virt_to_page()
+		 * work with aliases.  Getting the direct map
+		 * address ensures that we get a _writeable_
+		 * alias for the memset().
+		 */
+		direct_map_addr = page_address(page);
 		if ((unsigned int)poison <= 0xFF)
-			memset(pos, poison, PAGE_SIZE);
-		free_reserved_page(virt_to_page(pos));
+			memset(direct_map_addr, poison, PAGE_SIZE);
+
+		free_reserved_page(page);
 	}
 
 	if (pages && s)

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dave Hansen <[email protected]>

commit 9f515cdb411ef34f1aaf4c40bb0c932cf6db5de1 upstream.

The x86 code has several places where it frees parts of kernel image:

1. Unused SMP alternative
2. __init code
3. The hole between text and rodata
4. The hole between rodata and data

We call free_init_pages() to do this. Strangely, we convert the symbol addresses to kernel direct map addresses in some cases (#3, #4) but not others (#1, #2).

The virt_to_page() and the other code in free_reserved_area() now works fine for for symbol addresses on x86, so don't bother converting the addresses to direct map addresses before freeing them.

---
 arch/x86/mm/init_64.c |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

@@ -1283,12 +1283,8 @@ void mark_rodata_ro(void)
 	set_memory_ro(start, (end-start) >> PAGE_SHIFT);
 #endif
 
-	free_init_pages("unused kernel",
-			(unsigned long) __va(__pa_symbol(text_end)),
-			(unsigned long) __va(__pa_symbol(rodata_start)));
-	free_init_pages("unused kernel",
-			(unsigned long) __va(__pa_symbol(rodata_end)),
-			(unsigned long) __va(__pa_symbol(_sdata)));
+	free_init_pages("unused kernel", text_end, rodata_start);
+	free_init_pages("unused kernel", rodata_end, _sdata);
 
 	debug_checkwx();
 

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dave Hansen <[email protected]>

commit 6ea2738e0ca0e626c75202fb051c1e88d7a950fa upstream.

When chunks of the kernel image are freed, free_init_pages() is used directly. Consolidate the three sites that do this. Also update the string to give an incrementally better description of that memory versus what was there before.

---
 arch/x86/include/asm/processor.h |    1 +
 arch/x86/mm/init.c               |   15 ++++++++++++---
 arch/x86/mm/init_64.c            |    4 ++--
 3 files changed, 15 insertions(+), 5 deletions(-)

@@ -971,6 +971,7 @@ static inline uint32_t hypervisor_cpuid_
 
 extern unsigned long arch_align_stack(unsigned long sp);
 extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
+extern void free_kernel_image_pages(void *begin, void *end);
 
 void default_idle(void);
 #ifdef	CONFIG_XEN

@@ -775,13 +775,22 @@ void free_init_pages(char *what, unsigne
 	}
 }
 
+/*
+ * begin/end can be in the direct map or the "high kernel mapping"
+ * used for the kernel image only.  free_init_pages() will do the
+ * right thing for either kind of address.
+ */
+void free_kernel_image_pages(void *begin, void *end)
+{
+	free_init_pages("unused kernel image",
+			(unsigned long)begin, (unsigned long)end);
+}
+
 void __ref free_initmem(void)
 {
 	e820__reallocate_tables();
 
-	free_init_pages("unused kernel",
-			(unsigned long)(&__init_begin),
-			(unsigned long)(&__init_end));
+	free_kernel_image_pages(&__init_begin, &__init_end);
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD

@@ -1283,8 +1283,8 @@ void mark_rodata_ro(void)
 	set_memory_ro(start, (end-start) >> PAGE_SHIFT);
 #endif
 
-	free_init_pages("unused kernel", text_end, rodata_start);
-	free_init_pages("unused kernel", rodata_end, _sdata);
+	free_kernel_image_pages((void *)text_end, (void *)rodata_start);
+	free_kernel_image_pages((void *)rodata_end, (void *)_sdata);
 
 	debug_checkwx();
 

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dave Hansen <[email protected]>

commit c40a56a7818cfe735fc93a69e1875f8bba834483 upstream.

The kernel image is mapped into two places in the virtual address space (addresses without KASLR, of course):

1. The kernel direct map (0xffff880000000000)
2. The "high kernel map" (0xffffffff81000000)

We actually execute out of #2. If we get the address of a kernel symbol, it points to #2, but almost all physical-to-virtual translations point to

Parts of the "high kernel map" alias are mapped in the userspace page tables with the Global bit for performance reasons. The parts that we map to userspace do not (er, should not) have secrets. When PTI is enabled then the global bit is usually not set in the high mapping and just used to compensate for poor performance on systems which lack PCID.

This is fine, except that some areas in the kernel image that are adjacent to the non-secret-containing areas are unused holes. We free these holes back into the normal page allocator and reuse them as normal kernel memory. The memory will, of course, get *used* via the normal map, but the alias mapping is kept.

This otherwise unused alias mapping of the holes will, by default keep the Global bit, be mapped out to userspace, and be vulnerable to Meltdown.

Remove the alias mapping of these pages entirely. This is likely to fracture the 2M page mapping the kernel image near these areas, but this should affect a minority of the area.

The pageattr code changes *all* aliases mapping the physical pages that it operates on (by default). We only want to modify a single alias, so we need to tweak its behavior.

This unmapping behavior is currently dependent on PTI being in place. Going forward, we should at least consider doing this for all configurations. Having an extra read-write alias for memory is not exactly ideal for debugging things like random memory corruption and this does undercut features like DEBUG_PAGEALLOC or future work like eXclusive Page Frame Ownership (XPFO).

Before this patch:

current_kernel:---[ High Kernel Mapping ]---

current_kernel-0xffffffff80000000-0xffffffff81000000          16M                               pmd
current_kernel-0xffffffff81000000-0xffffffff81e00000          14M     ro         PSE     GLB x  pmd
current_kernel-0xffffffff81e00000-0xffffffff81e11000          68K     ro                 GLB x  pte
current_kernel-0xffffffff81e11000-0xffffffff82000000        1980K     RW                     NX pte
current_kernel-0xffffffff82000000-0xffffffff82600000           6M     ro         PSE     GLB NX pmd
current_kernel-0xffffffff82600000-0xffffffff82c00000           6M     RW         PSE         NX pmd
current_kernel-0xffffffff82c00000-0xffffffff82e00000           2M     RW                     NX pte
current_kernel-0xffffffff82e00000-0xffffffff83200000           4M     RW         PSE         NX pmd

current_kernel-0xffffffff83200000-0xffffffffa0000000 462M pmd

current_user:---[ High Kernel Mapping ]---

  current_user-0xffffffff80000000-0xffffffff81000000          16M                               pmd
  current_user-0xffffffff81000000-0xffffffff81e00000          14M     ro         PSE     GLB x  pmd
  current_user-0xffffffff81e00000-0xffffffff81e11000          68K     ro                 GLB x  pte

current_user-0xffffffff81e11000-0xffffffff82000000 1980K RW NX pte
current_user-0xffffffff82000000-0xffffffff82600000 6M ro PSE GLB NX pmd
current_user-0xffffffff82600000-0xffffffffa0000000 474M pmd

After this patch:

current_kernel:---[ High Kernel Mapping ]---

current_kernel-0xffffffff80000000-0xffffffff81000000          16M                               pmd
current_kernel-0xffffffff81000000-0xffffffff81e00000          14M     ro         PSE     GLB x  pmd
current_kernel-0xffffffff81e00000-0xffffffff81e11000          68K     ro                 GLB x  pte
current_kernel-0xffffffff81e11000-0xffffffff82000000        1980K                               pte
current_kernel-0xffffffff82000000-0xffffffff82400000           4M     ro         PSE     GLB NX pmd
current_kernel-0xffffffff82400000-0xffffffff82488000         544K     ro                     NX pte
current_kernel-0xffffffff82488000-0xffffffff82600000        1504K                               pte
current_kernel-0xffffffff82600000-0xffffffff82c00000           6M     RW         PSE         NX pmd
current_kernel-0xffffffff82c00000-0xffffffff82c0d000          52K     RW                     NX pte

current_kernel-0xffffffff82c0d000-0xffffffff82dc0000 1740K pte

current_user:---[ High Kernel Mapping ]---

  current_user-0xffffffff80000000-0xffffffff81000000          16M                               pmd
  current_user-0xffffffff81000000-0xffffffff81e00000          14M     ro         PSE     GLB x  pmd
  current_user-0xffffffff81e00000-0xffffffff81e11000          68K     ro                 GLB x  pte
  current_user-0xffffffff81e11000-0xffffffff82000000        1980K                               pte

current_user-0xffffffff82000000-0xffffffff82400000 4M ro PSE GLB NX pmd
current_user-0xffffffff82400000-0xffffffff82488000 544K ro NX pte
current_user-0xffffffff82488000-0xffffffff82600000 1504K pte
current_user-0xffffffff82600000-0xffffffffa0000000 474M pmd

[ tglx: Do not unmap on 32bit as there is only one mapping ]

---
 arch/x86/include/asm/set_memory.h |    1 +
 arch/x86/mm/init.c                |   26 ++++++++++++++++++++++++--
 arch/x86/mm/pageattr.c            |   13 +++++++++++++
 3 files changed, 38 insertions(+), 2 deletions(-)

@@ -46,6 +46,7 @@ int set_memory_np(unsigned long addr, in
 int set_memory_4k(unsigned long addr, int numpages);
 int set_memory_encrypted(unsigned long addr, int numpages);
 int set_memory_decrypted(unsigned long addr, int numpages);
+int set_memory_np_noalias(unsigned long addr, int numpages);
 
 int set_memory_array_uc(unsigned long *addr, int addrinarray);
 int set_memory_array_wc(unsigned long *addr, int addrinarray);

@@ -782,8 +782,30 @@ void free_init_pages(char *what, unsigne
  */
 void free_kernel_image_pages(void *begin, void *end)
 {
-	free_init_pages("unused kernel image",
-			(unsigned long)begin, (unsigned long)end);
+	unsigned long begin_ul = (unsigned long)begin;
+	unsigned long end_ul = (unsigned long)end;
+	unsigned long len_pages = (end_ul - begin_ul) >> PAGE_SHIFT;
+
+
+	free_init_pages("unused kernel image", begin_ul, end_ul);
+
+	/*
+	 * PTI maps some of the kernel into userspace.  For performance,
+	 * this includes some kernel areas that do not contain secrets.
+	 * Those areas might be adjacent to the parts of the kernel image
+	 * being freed, which may contain secrets.  Remove the "high kernel
+	 * image mapping" for these freed areas, ensuring they are not even
+	 * potentially vulnerable to Meltdown regardless of the specific
+	 * optimizations PTI is currently using.
+	 *
+	 * The "noalias" prevents unmapping the direct map alias which is
+	 * needed to access the freed pages.
+	 *
+	 * This is only valid for 64bit kernels. 32bit has only one mapping
+	 * which can't be treated in this way for obvious reasons.
+	 */
+	if (IS_ENABLED(CONFIG_X86_64) && cpu_feature_enabled(X86_FEATURE_PTI))
+		set_memory_np_noalias(begin_ul, len_pages);
 }
 
 void __ref free_initmem(void)

@@ -53,6 +53,7 @@ static DEFINE_SPINLOCK(cpa_lock);
 #define CPA_FLUSHTLB 1
 #define CPA_ARRAY 2
 #define CPA_PAGES_ARRAY 4
+#define CPA_NO_CHECK_ALIAS 8 /* Do not search for aliases */
 
 #ifdef CONFIG_PROC_FS
 static unsigned long direct_pages_count[PG_LEVEL_NUM];

@@ -1486,6 +1487,9 @@ static int change_page_attr_set_clr(unsi
 
 	/* No alias checking for _NX bit modifications */
 	checkalias = (pgprot_val(mask_set) | pgprot_val(mask_clr)) != _PAGE_NX;
+	/* Has caller explicitly disabled alias checking? */
+	if (in_flag & CPA_NO_CHECK_ALIAS)
+		checkalias = 0;
 
 	ret = __change_page_attr_set_clr(&cpa, checkalias);
 

@@ -1772,6 +1776,15 @@ int set_memory_np(unsigned long addr, in
 	return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_PRESENT), 0);
 }
 
+int set_memory_np_noalias(unsigned long addr, int numpages)
+{
+	int cpa_flags = CPA_NO_CHECK_ALIAS;
+
+	return change_page_attr_set_clr(&addr, numpages, __pgprot(0),
+					__pgprot(_PAGE_PRESENT), 0,
+					cpa_flags, NULL);
+}
+
 int set_memory_4k(unsigned long addr, int numpages)
 {
 	return change_page_attr_set_clr(&addr, numpages, __pgprot(0),

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Michael Ellerman <[email protected]>

commit 6d44acae1937b81cf8115ada8958e04f601f3f2e upstream.

When I added the spectre_v2 information in sysfs, I included the availability of the ori31 speculation barrier.

Although the ori31 barrier can be used to mitigate v2, it's primarily intended as a spectre v1 mitigation. Spectre v2 is mitigated by hardware changes.

So rework the sysfs files to show the ori31 information in the spectre_v1 file, rather than v2.

Currently we display eg:

  $ grep . spectre_v*
  spectre_v1:Mitigation: __user pointer sanitization
  spectre_v2:Mitigation: Indirect branch cache disabled, ori31 speculation barrier enabled

After:

  $ grep . spectre_v*
  spectre_v1:Mitigation: __user pointer sanitization, ori31 speculation barrier enabled
  spectre_v2:Mitigation: Indirect branch cache disabled

---
 arch/powerpc/kernel/security.c |   27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

@@ -117,25 +117,35 @@ ssize_t cpu_show_meltdown(struct device
 
 ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	if (!security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR))
-		return sprintf(buf, "Not affected\n");
+	struct seq_buf s;
+
+	seq_buf_init(&s, buf, PAGE_SIZE - 1);
+
+	if (security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR)) {
+		if (barrier_nospec_enabled)
+			seq_buf_printf(&s, "Mitigation: __user pointer sanitization");
+		else
+			seq_buf_printf(&s, "Vulnerable");
 
-	if (barrier_nospec_enabled)
-		return sprintf(buf, "Mitigation: __user pointer sanitization\n");
+		if (security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31))
+			seq_buf_printf(&s, ", ori31 speculation barrier enabled");
 
-	return sprintf(buf, "Vulnerable\n");
+		seq_buf_printf(&s, "\n");
+	} else
+		seq_buf_printf(&s, "Not affected\n");
+
+	return s.len;
 }
 
 ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	bool bcs, ccd, ori;
 	struct seq_buf s;
+	bool bcs, ccd;
 
 	seq_buf_init(&s, buf, PAGE_SIZE - 1);
 
 	bcs = security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED);
 	ccd = security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED);
-	ori = security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31);
 
 	if (bcs || ccd) {
 		seq_buf_printf(&s, "Mitigation: ");

@@ -151,9 +161,6 @@ ssize_t cpu_show_spectre_v2(struct devic
 	} else
 		seq_buf_printf(&s, "Vulnerable");
 
-	if (ori)
-		seq_buf_printf(&s, ", ori31 speculation barrier enabled");
-
 	seq_buf_printf(&s, "\n");
 
 	return s.len;

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jeremy Cline <[email protected]>

commit 1a5d5e5d51e75a5bca67dadbcea8c841934b7b85 upstream.

'ac->ac_g_ex.fe_len' is a user-controlled value which is used in the derivation of 'ac->ac_2order'. 'ac->ac_2order', in turn, is used to index arrays which makes it a potential spectre gadget. Fix this by sanitizing the value assigned to 'ac->ac2_order'. This covers the following accesses found with the help of smatch:

* fs/ext4/mballoc.c:1896 ext4_mb_simple_scan_group() warn: potential spectre issue 'grp->bb_counters' [w] (local cap)

* fs/ext4/mballoc.c:445 mb_find_buddy() warn: potential spectre issue 'EXT4_SB(e4b->bd_sb)->s_mb_offsets' [r] (local cap)

* fs/ext4/mballoc.c:446 mb_find_buddy() warn: potential spectre issue 'EXT4_SB(e4b->bd_sb)->s_mb_maxs' [r] (local cap)

---
 fs/ext4/mballoc.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -14,6 +14,7 @@
 #include <linux/log2.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/nospec.h>
 #include <linux/backing-dev.h>
 #include <trace/events/ext4.h>
 

@@ -2140,7 +2141,8 @@ ext4_mb_regular_allocator(struct ext4_al
 		 * This should tell if fe_len is exactly power of 2
 		 */
 		if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
-			ac->ac_2order = i - 1;
+			ac->ac_2order = array_index_nospec(i - 1,
+							   sb->s_blocksize_bits + 2);
 	}
 
 	/* if stream allocation is enabled, use global goal */

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Gustavo A. R. Silva <[email protected]>

commit de5372da605d3bca46e3102bab51b7e1c0e0a6f6 upstream.

info.index can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability.

This issue was detected with the help of Smatch:

drivers/gpu/drm/i915/gvt/kvmgt.c:1232 intel_vgpu_ioctl() warn:
potential spectre issue 'vgpu->vdev.region' [r]

Fix this by sanitizing info.index before indirectly using it to index vgpu->vdev.region

Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1].

[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2

---
 drivers/gpu/drm/i915/gvt/kvmgt.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

@@ -43,6 +43,8 @@
 #include <linux/mdev.h>
 #include <linux/debugfs.h>
 
+#include <linux/nospec.h>
+
 #include "i915_drv.h"
 #include "gvt.h"
 

@@ -1084,7 +1086,8 @@ static long intel_vgpu_ioctl(struct mdev
 	} else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
 		struct vfio_region_info info;
 		struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
-		int i, ret;
+		unsigned int i;
+		int ret;
 		struct vfio_region_info_cap_sparse_mmap *sparse = NULL;
 		size_t size;
 		int nr_areas = 1;

@@ -1169,6 +1172,10 @@ static long intel_vgpu_ioctl(struct mdev
 				if (info.index >= VFIO_PCI_NUM_REGIONS +
 						vgpu->vdev.num_regions)
 					return -EINVAL;
+				info.index =
+					array_index_nospec(info.index,
+							VFIO_PCI_NUM_REGIONS +
+							vgpu->vdev.num_regions);
 
 				i = info.index - VFIO_PCI_NUM_REGIONS;
 

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Gustavo A. R. Silva <[email protected]>

commit ddf74e79a54070f277ae520722d3bab7f7a6c67a upstream.

idx can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability.

This issue was detected with the help of Smatch:

drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c:408 amdgpu_set_pp_force_state()
warn: potential spectre issue 'data.states'

Fix this by sanitizing idx before using it to index data.states

Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1].

[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2

---
 drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -31,7 +31,7 @@
 #include <linux/power_supply.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
-
+#include <linux/nospec.h>
 
 static int amdgpu_debugfs_pm_init(struct amdgpu_device *adev);
 

@@ -393,6 +393,7 @@ static ssize_t amdgpu_set_pp_force_state
 			count = -EINVAL;
 			goto fail;
 		}
+		idx = array_index_nospec(idx, ARRAY_SIZE(data.states));
 
 		amdgpu_dpm_get_pp_num_states(adev, &data);
 		state = data.states[idx];

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Rafael J. Wysocki <[email protected]>

commit 9d64b539b738fc181442caab95f1f76d9bd58539 upstream.

Commit 26112ddc254c (PCI / ACPI / PM: Resume bridges w/o drivers on suspend-to-RAM) attempted to fix a functional regression resulting from commit c62ec4610c40 (PM / core: Fix direct_complete handling for devices with no callbacks) by resuming PCI bridges without drivers (that is, "parallel PCI" ones) during system-wide suspend if the target system state is not ACPI S0 (working state).

That turns out insufficient, however, as it is reported that, at least in one case, the platform firmware gets confused if a PCIe root port is suspended before entering the ACPI S3 sleep state. That issue was exposed by commit 77b3729ca03 (PCI / PM: Use SMART_SUSPEND and LEAVE_SUSPENDED flags for PCIe ports) that allowed PCIe ports to stay in runtime suspend during system-wide suspend (which is OK for suspend-to-idle, but turns out to be problematic otherwise).

For this reason, drop the driver check from acpi_pci_need_resume() and resume all bridges (including PCIe ports with drivers) during system-wide suspend if the target system state is not ACPI S0.

[If the target system state is ACPI S0, it means suspend-to-idle
and the platform firmware is not going to be invoked to actually suspend the system, so there is no need to resume the bridges in that case.]

---
 drivers/pci/pci-acpi.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

@@ -632,13 +632,11 @@ static bool acpi_pci_need_resume(struct
 	/*
 	 * In some cases (eg. Samsung 305V4A) leaving a bridge in suspend over
 	 * system-wide suspend/resume confuses the platform firmware, so avoid
-	 * doing that, unless the bridge has a driver that should take care of
-	 * the PM handling.  According to Section 16.1.6 of ACPI 6.2, endpoint
+	 * doing that.  According to Section 16.1.6 of ACPI 6.2, endpoint
 	 * devices are expected to be in D3 before invoking the S3 entry path
 	 * from the firmware, so they should not be affected by this issue.
 	 */
-	if (pci_is_bridge(dev) && !dev->driver &&
-	    acpi_target_system_state() != ACPI_STATE_S0)
+	if (pci_is_bridge(dev) && acpi_target_system_state() != ACPI_STATE_S0)
 		return true;
 
 	if (!adev || !acpi_device_power_manageable(adev))

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Lukas Wunner <[email protected]>

commit 4ce6435820d1f1cc2c2788e232735eb244bcc8a3 upstream.

If addition of sysfs files fails on registration of a hotplug slot, the struct pci_slot as well as the entry in the slot_list is leaked. The issue has been present since the hotplug core was introduced in 2002:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Perhaps the idea was that even though sysfs addition fails, the slot should still be usable. But that's not how drivers use the interface, they abort probe if a non-zero value is returned.

---
 drivers/pci/hotplug/pci_hotplug_core.c |    9 +++++++++
 1 file changed, 9 insertions(+)

@@ -438,8 +438,17 @@ int __pci_hp_register(struct hotplug_slo
 	list_add(&slot->slot_list, &pci_hotplug_slot_list);
 
 	result = fs_add_slot(pci_slot);
+	if (result)
+		goto err_list_del;
+
 	kobject_uevent(&pci_slot->kobj, KOBJ_ADD);
 	dbg("Added slot %s to the list\n", name);
+	goto out;
+
+err_list_del:
+	list_del(&slot->slot_list);
+	pci_slot->hotplug = NULL;
+	pci_destroy_slot(pci_slot);
 out:
 	mutex_unlock(&pci_hp_mutex);
 	return result;

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Zachary Zhang <[email protected]>

commit 91a2968e245d6ba616db37001fa1a043078b1a65 upstream.

The PCIE I/O and MEM resource allocation mechanism is that root bus goes through the following steps:

1. Check PCI bridges' range and computes I/O and Mem base/limits.

2. Sort all subordinate devices I/O and MEM resource requirements and allocate the resources and writes/updates subordinate devices' requirements to PCI bridges I/O and Mem MEM/limits registers.

Currently, PCI Aardvark driver only handles the second step and lacks the first step, so there is an I/O and MEM resource allocation failure when using a PCI switch. This commit fixes that by sizing bridges before doing the resource allocation.

driver")

---
 drivers/pci/controller/pci-aardvark.c |    1 +
 1 file changed, 1 insertion(+)

@@ -952,6 +952,7 @@ static int advk_pcie_probe(struct platfo
 
 	bus = bridge->bus;
 
+	pci_bus_size_bridges(bus);
 	pci_bus_assign_resources(bus);
 
 	list_for_each_entry(child, &bus->children, node)

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Myron Stowe <[email protected]>

commit 3dbe97efe8bf450b183d6dee2305cbc032e6b8a4 upstream.

PCIe r4.0, sec 9.3.5.4, "Device Control Register", shows both Max_Payload_Size (MPS) and Max_Read_request_Size (MRRS) to be 'RsvdP' for VFs. Just prior to the table it states:

"PF and VF functionality is defined in Section 7.5.3.4 except where
noted in Table 9-16. For VF fields marked 'RsvdP', the PF setting applies to the VF."

All of which implies that with respect to Max_Payload_Size Supported (MPSS), MPS, and MRRS values, we should not be paying any attention to the VF's fields, but rather only to the PF's. Only looking at the PF's fields also logically makes sense as it's the sole physical interface to the PCIe bus.

---
 drivers/pci/probe.c |    4 ++++
 1 file changed, 4 insertions(+)

@@ -1730,6 +1730,10 @@ static void pci_configure_mps(struct pci
 	if (!pci_is_pcie(dev) || !bridge || !pci_is_pcie(bridge))
 		return;
 
+	/* MPS and MRRS fields are of type 'RsvdP' for VFs, short-circuit out */
+	if (dev->is_virtfn)
+		return;
+
 	mps = pcie_get_mps(dev);
 	p_mps = pcie_get_mps(bridge);
 

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Lukas Wunner <[email protected]>

commit 281e878eab191cce4259abbbf1a0322e3adae02c upstream.

When pciehp is unbound (e.g. on unplug of a Thunderbolt device), the hotplug_slot struct is deregistered and thus freed before freeing the IRQ. The IRQ handler and the work items it schedules print the slot name referenced from the freed structure in various informational and debug log messages, each time resulting in a quadruple dereference of freed pointers (hotplug_slot -> pci_slot -> kobject -> name).

At best the slot name is logged as "(null)", at worst kernel memory is exposed in logs or the driver crashes:

pciehp 0000:10:00.0:pcie204: Slot((null)): Card not present

An attacker may provoke the bug by unplugging multiple devices on a Thunderbolt daisy chain at once. Unplugging can also be simulated by powering down slots via sysfs. The bug is particularly easy to trigger in poll mode.

It has been present since the driver's introduction in 2004:
https://git.kernel.org/tglx/history/c/c16b4b14d980

Fix by rearranging teardown such that the IRQ is freed first. Run the work items queued by the IRQ handler to completion before freeing the hotplug_slot struct by draining the work queue from the ->release_slot callback which is invoked by pci_hp_deregister().

---
 drivers/pci/hotplug/pciehp.h      |    1 +
 drivers/pci/hotplug/pciehp_core.c |    7 +++++++
 drivers/pci/hotplug/pciehp_hpc.c  |    5 ++---
 3 files changed, 10 insertions(+), 3 deletions(-)

@@ -119,6 +119,7 @@ int pciehp_unconfigure_device(struct slo
 void pciehp_queue_pushbutton_work(struct work_struct *work);
 struct controller *pcie_init(struct pcie_device *dev);
 int pcie_init_notification(struct controller *ctrl);
+void pcie_shutdown_notification(struct controller *ctrl);
 int pciehp_enable_slot(struct slot *p_slot);
 int pciehp_disable_slot(struct slot *p_slot);
 void pcie_reenable_notification(struct controller *ctrl);

@@ -62,6 +62,12 @@ static int reset_slot(struct hotplug_slo
  */
 static void release_slot(struct hotplug_slot *hotplug_slot)
 {
+	struct slot *slot = hotplug_slot->private;
+
+	/* queued work needs hotplug_slot name */
+	cancel_delayed_work(&slot->work);
+	drain_workqueue(slot->wq);
+
 	kfree(hotplug_slot->ops);
 	kfree(hotplug_slot->info);
 	kfree(hotplug_slot);

@@ -264,6 +270,7 @@ static void pciehp_remove(struct pcie_de
 {
 	struct controller *ctrl = get_service_data(dev);
 
+	pcie_shutdown_notification(ctrl);
 	cleanup_slot(ctrl);
 	pciehp_release_ctrl(ctrl);
 }

@@ -765,7 +765,7 @@ int pcie_init_notification(struct contro
 	return 0;
 }
 
-static void pcie_shutdown_notification(struct controller *ctrl)
+void pcie_shutdown_notification(struct controller *ctrl)
 {
 	if (ctrl->notification_enabled) {
 		pcie_disable_notification(ctrl);

@@ -800,7 +800,7 @@ abort:
 static void pcie_cleanup_slot(struct controller *ctrl)
 {
 	struct slot *slot = ctrl->slot;
-	cancel_delayed_work(&slot->work);
+
 	destroy_workqueue(slot->wq);
 	kfree(slot);
 }

@@ -893,7 +893,6 @@ abort:
 
 void pciehp_release_ctrl(struct controller *ctrl)
 {
-	pcie_shutdown_notification(ctrl);
 	pcie_cleanup_slot(ctrl);
 	kfree(ctrl);
 }

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Lukas Wunner <[email protected]>

commit 1204e35bedf4e5015cda559ed8c84789a6dae24e upstream.

Commit b440bde74f04 ("PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device") iterates over the devices on a hotplug port's subordinate bus in pciehp's IRQ handler without acquiring pci_bus_sem. It is thus possible for a user to cause a crash by concurrently manipulating the device list, e.g. by disabling slot power via sysfs on a different CPU or by initiating a remove/rescan via sysfs.

This can't be fixed by acquiring pci_bus_sem because it may sleep. The simplest fix is to avoid the list iteration altogether and just check the ignore_hotplug flag on the port itself. This works because pci_ignore_hotplug() sets the flag both on the device as well as on its parent bridge.

We do lose the ability to print the name of the device blocking hotplug in the debug message, but that's probably bearable.

---
 drivers/pci/hotplug/pciehp_hpc.c |   13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

@@ -539,8 +539,6 @@ static irqreturn_t pciehp_isr(int irq, v
 {
 	struct controller *ctrl = (struct controller *)dev_id;
 	struct pci_dev *pdev = ctrl_dev(ctrl);
-	struct pci_bus *subordinate = pdev->subordinate;
-	struct pci_dev *dev;
 	struct slot *slot = ctrl->slot;
 	u16 status, events;
 	u8 present;

@@ -588,14 +586,9 @@ static irqreturn_t pciehp_isr(int irq, v
 		wake_up(&ctrl->queue);
 	}
 
-	if (subordinate) {
-		list_for_each_entry(dev, &subordinate->devices, bus_list) {
-			if (dev->ignore_hotplug) {
-				ctrl_dbg(ctrl, "ignoring hotplug event %#06x (%s requested no hotplug)\n",
-					 events, pci_name(dev));
-				return IRQ_HANDLED;
-			}
-		}
+	if (pdev->ignore_hotplug) {
+		ctrl_dbg(ctrl, "ignoring hotplug event %#06x\n", events);
+		return IRQ_HANDLED;
 	}
 
 	/* Check Attention Button Pressed */

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hans de Goede <[email protected]>

commit c463a158cb6c5d9a85b7d894cd4f8116e8bd6be0 upstream.

acpi_gsb_i2c_write_bytes() returns i2c_transfer()'s return value, which is the number of transfers executed on success, so 1.

The ACPI code expects us to store 0 in gsb->status for success, not 1.

Specifically this breaks the following code in the Thinkpad 8 DSDT:

            ECWR = I2CW = ECWR /* \_SB_.I2C1.BAT0.ECWR */
            If ((ECST == Zero))
            {
                ECRD = I2CR /* \_SB_.I2C1.I2CR */
            }

Before this commit we set ECST to 1, causing the read to never happen breaking battery monitoring on the Thinkpad 8.

This commit makes acpi_gsb_i2c_write_bytes() return 0 when i2c_transfer() returns 1, so the single write transfer completed successfully, and makes it return -EIO on for other (unexpected) return values >= 0.

---
 drivers/i2c/i2c-core-acpi.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

@@ -482,11 +482,16 @@ static int acpi_gsb_i2c_write_bytes(stru
 	msgs[0].buf = buffer;
 
 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
-	if (ret < 0)
-		dev_err(&client->adapter->dev, "i2c write failed\n");
 
 	kfree(buffer);
-	return ret;
+
+	if (ret < 0) {
+		dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
+		return ret;
+	}
+
+	/* 1 transfer must have completed successfully */
+	return (ret == 1) ? 0 : -EIO;
 }
 
 static acpi_status

4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jann Horn <[email protected]>

commit a13f085d111e90469faf2d9965eb39b11c114d7e upstream.

This fixes the following issues:

- When a buffer size is supplied to reiserfs_listxattr() such that each individual name fits, but the concatenation of all names doesn't fit, reiserfs_listxattr() overflows the supplied buffer. This leads to a kernel heap overflow (verified using KASAN) followed by an out-of-bounds usercopy and is therefore a security bug.

- When a buffer size is supplied to reiserfs_listxattr() such that a name doesn't fit, -ERANGE should be returned. But reiserfs instead just truncates the list of names; I have verified that if the only xattr on a file has a longer name than the supplied buffer length, listxattr() incorrectly returns zero.

With my patch applied, -ERANGE is returned in both cases and the memory corruption doesn't happen anymore.

Credit for making me clean this code up a bit goes to Al Viro, who pointed out that the ->actor calling convention is suboptimal and should be changed.

---
 fs/reiserfs/xattr.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -792,8 +792,10 @@ static int listxattr_filler(struct dir_c
 			return 0;
 		size = namelen + 1;
 		if (b->buf) {
-			if (size > b->size)
+			if (b->pos + size > b->size) {
+				b->pos = -ERANGE;
 				return -ERANGE;
+			}
 			memcpy(b->buf + b->pos, name, namelen);
 			b->buf[b->pos + namelen] = 0;
 		}

Compiled and booted on my test system. No dmesg regressions.

thanks,
-- Shuah

Thanks for testing all of these and letting me know.

greg k-h

Build results:

	total: 134 pass: 134 fail: 0
Qemu test results:
	total: 302 pass: 302 fail: 0

Details are available at http://kerneltests.org/builders.

Guenter

Yeah! Thanks for testing all of these and reporting all of the issues.

greg k-h

Results from Linaro’s test farm.
No regressions on arm64, arm and x86_64.

Summary
------------------------------------------------------------------------

kernel: 4.18.5-rc1
git repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
git branch: linux-4.18.y
git commit: c456dc1ec5f92b9bab9cd6c3fa53ab7cc32c8d79
git describe: v4.18.4-23-gc456dc1ec5f9
Test details: https://qa-reports.linaro.org/lkft/linux-stable-rc-4.18-oe/build/v4.18.4-23-gc456dc1ec5f9

No regressions (compared to build v4.18.3)

Ran 11322 total tests in the following environments and test suites.

Environments
--------------
- dragonboard-410c - arm64
- hi6220-hikey - arm64
- juno-r2 - arm64
- x15 - arm
- x86_64

Test Suites
-----------
* boot
* kselftest
* libhugetlbfs
* ltp-cap_bounds-tests
* ltp-containers-tests
* ltp-fcntl-locktests-tests
* ltp-filecaps-tests
* ltp-fs-tests
* ltp-fs_bind-tests
* ltp-fs_perms_simple-tests
* ltp-fsx-tests
* ltp-hugetlb-tests
* ltp-io-tests
* ltp-ipc-tests
* ltp-math-tests
* ltp-nptl-tests
* ltp-pty-tests
* ltp-sched-tests
* ltp-securebits-tests
* ltp-syscalls-tests
* ltp-timers-tests
* ltp-cve-tests
* ltp-open-posix-tests
* kselftest-vsyscall-mode-native
* kselftest-vsyscall-mode-none

Linaro LKFT
https://lkft.linaro.org

Great, thanks for testing all of these and letting me know.

greg k-h