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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /mm/memfd.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to 'mm/memfd.c')
-rw-r--r--mm/memfd.c343
1 files changed, 343 insertions, 0 deletions
diff --git a/mm/memfd.c b/mm/memfd.c
new file mode 100644
index 000000000..08f5f8304
--- /dev/null
+++ b/mm/memfd.c
@@ -0,0 +1,343 @@
+/*
+ * memfd_create system call and file sealing support
+ *
+ * Code was originally included in shmem.c, and broken out to facilitate
+ * use by hugetlbfs as well as tmpfs.
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/pagemap.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/khugepaged.h>
+#include <linux/syscalls.h>
+#include <linux/hugetlb.h>
+#include <linux/shmem_fs.h>
+#include <linux/memfd.h>
+#include <uapi/linux/memfd.h>
+
+/*
+ * We need a tag: a new tag would expand every xa_node by 8 bytes,
+ * so reuse a tag which we firmly believe is never set or cleared on tmpfs
+ * or hugetlbfs because they are memory only filesystems.
+ */
+#define MEMFD_TAG_PINNED PAGECACHE_TAG_TOWRITE
+#define LAST_SCAN 4 /* about 150ms max */
+
+static void memfd_tag_pins(struct xa_state *xas)
+{
+ struct page *page;
+ int latency = 0;
+ int cache_count;
+
+ lru_add_drain();
+
+ xas_lock_irq(xas);
+ xas_for_each(xas, page, ULONG_MAX) {
+ cache_count = 1;
+ if (!xa_is_value(page) &&
+ PageTransHuge(page) && !PageHuge(page))
+ cache_count = HPAGE_PMD_NR;
+
+ if (!xa_is_value(page) &&
+ page_count(page) - total_mapcount(page) != cache_count)
+ xas_set_mark(xas, MEMFD_TAG_PINNED);
+ if (cache_count != 1)
+ xas_set(xas, page->index + cache_count);
+
+ latency += cache_count;
+ if (latency < XA_CHECK_SCHED)
+ continue;
+ latency = 0;
+
+ xas_pause(xas);
+ xas_unlock_irq(xas);
+ cond_resched();
+ xas_lock_irq(xas);
+ }
+ xas_unlock_irq(xas);
+}
+
+/*
+ * Setting SEAL_WRITE requires us to verify there's no pending writer. However,
+ * via get_user_pages(), drivers might have some pending I/O without any active
+ * user-space mappings (eg., direct-IO, AIO). Therefore, we look at all pages
+ * and see whether it has an elevated ref-count. If so, we tag them and wait for
+ * them to be dropped.
+ * The caller must guarantee that no new user will acquire writable references
+ * to those pages to avoid races.
+ */
+static int memfd_wait_for_pins(struct address_space *mapping)
+{
+ XA_STATE(xas, &mapping->i_pages, 0);
+ struct page *page;
+ int error, scan;
+
+ memfd_tag_pins(&xas);
+
+ error = 0;
+ for (scan = 0; scan <= LAST_SCAN; scan++) {
+ int latency = 0;
+ int cache_count;
+
+ if (!xas_marked(&xas, MEMFD_TAG_PINNED))
+ break;
+
+ if (!scan)
+ lru_add_drain_all();
+ else if (schedule_timeout_killable((HZ << scan) / 200))
+ scan = LAST_SCAN;
+
+ xas_set(&xas, 0);
+ xas_lock_irq(&xas);
+ xas_for_each_marked(&xas, page, ULONG_MAX, MEMFD_TAG_PINNED) {
+ bool clear = true;
+
+ cache_count = 1;
+ if (!xa_is_value(page) &&
+ PageTransHuge(page) && !PageHuge(page))
+ cache_count = HPAGE_PMD_NR;
+
+ if (!xa_is_value(page) && cache_count !=
+ page_count(page) - total_mapcount(page)) {
+ /*
+ * On the last scan, we clean up all those tags
+ * we inserted; but make a note that we still
+ * found pages pinned.
+ */
+ if (scan == LAST_SCAN)
+ error = -EBUSY;
+ else
+ clear = false;
+ }
+ if (clear)
+ xas_clear_mark(&xas, MEMFD_TAG_PINNED);
+
+ latency += cache_count;
+ if (latency < XA_CHECK_SCHED)
+ continue;
+ latency = 0;
+
+ xas_pause(&xas);
+ xas_unlock_irq(&xas);
+ cond_resched();
+ xas_lock_irq(&xas);
+ }
+ xas_unlock_irq(&xas);
+ }
+
+ return error;
+}
+
+static unsigned int *memfd_file_seals_ptr(struct file *file)
+{
+ if (shmem_file(file))
+ return &SHMEM_I(file_inode(file))->seals;
+
+#ifdef CONFIG_HUGETLBFS
+ if (is_file_hugepages(file))
+ return &HUGETLBFS_I(file_inode(file))->seals;
+#endif
+
+ return NULL;
+}
+
+#define F_ALL_SEALS (F_SEAL_SEAL | \
+ F_SEAL_SHRINK | \
+ F_SEAL_GROW | \
+ F_SEAL_WRITE | \
+ F_SEAL_FUTURE_WRITE)
+
+static int memfd_add_seals(struct file *file, unsigned int seals)
+{
+ struct inode *inode = file_inode(file);
+ unsigned int *file_seals;
+ int error;
+
+ /*
+ * SEALING
+ * Sealing allows multiple parties to share a tmpfs or hugetlbfs file
+ * but restrict access to a specific subset of file operations. Seals
+ * can only be added, but never removed. This way, mutually untrusted
+ * parties can share common memory regions with a well-defined policy.
+ * A malicious peer can thus never perform unwanted operations on a
+ * shared object.
+ *
+ * Seals are only supported on special tmpfs or hugetlbfs files and
+ * always affect the whole underlying inode. Once a seal is set, it
+ * may prevent some kinds of access to the file. Currently, the
+ * following seals are defined:
+ * SEAL_SEAL: Prevent further seals from being set on this file
+ * SEAL_SHRINK: Prevent the file from shrinking
+ * SEAL_GROW: Prevent the file from growing
+ * SEAL_WRITE: Prevent write access to the file
+ *
+ * As we don't require any trust relationship between two parties, we
+ * must prevent seals from being removed. Therefore, sealing a file
+ * only adds a given set of seals to the file, it never touches
+ * existing seals. Furthermore, the "setting seals"-operation can be
+ * sealed itself, which basically prevents any further seal from being
+ * added.
+ *
+ * Semantics of sealing are only defined on volatile files. Only
+ * anonymous tmpfs and hugetlbfs files support sealing. More
+ * importantly, seals are never written to disk. Therefore, there's
+ * no plan to support it on other file types.
+ */
+
+ if (!(file->f_mode & FMODE_WRITE))
+ return -EPERM;
+ if (seals & ~(unsigned int)F_ALL_SEALS)
+ return -EINVAL;
+
+ inode_lock(inode);
+
+ file_seals = memfd_file_seals_ptr(file);
+ if (!file_seals) {
+ error = -EINVAL;
+ goto unlock;
+ }
+
+ if (*file_seals & F_SEAL_SEAL) {
+ error = -EPERM;
+ goto unlock;
+ }
+
+ if ((seals & F_SEAL_WRITE) && !(*file_seals & F_SEAL_WRITE)) {
+ error = mapping_deny_writable(file->f_mapping);
+ if (error)
+ goto unlock;
+
+ error = memfd_wait_for_pins(file->f_mapping);
+ if (error) {
+ mapping_allow_writable(file->f_mapping);
+ goto unlock;
+ }
+ }
+
+ *file_seals |= seals;
+ error = 0;
+
+unlock:
+ inode_unlock(inode);
+ return error;
+}
+
+static int memfd_get_seals(struct file *file)
+{
+ unsigned int *seals = memfd_file_seals_ptr(file);
+
+ return seals ? *seals : -EINVAL;
+}
+
+long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ long error;
+
+ switch (cmd) {
+ case F_ADD_SEALS:
+ /* disallow upper 32bit */
+ if (arg > UINT_MAX)
+ return -EINVAL;
+
+ error = memfd_add_seals(file, arg);
+ break;
+ case F_GET_SEALS:
+ error = memfd_get_seals(file);
+ break;
+ default:
+ error = -EINVAL;
+ break;
+ }
+
+ return error;
+}
+
+#define MFD_NAME_PREFIX "memfd:"
+#define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1)
+#define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN)
+
+#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB)
+
+SYSCALL_DEFINE2(memfd_create,
+ const char __user *, uname,
+ unsigned int, flags)
+{
+ unsigned int *file_seals;
+ struct file *file;
+ int fd, error;
+ char *name;
+ long len;
+
+ if (!(flags & MFD_HUGETLB)) {
+ if (flags & ~(unsigned int)MFD_ALL_FLAGS)
+ return -EINVAL;
+ } else {
+ /* Allow huge page size encoding in flags. */
+ if (flags & ~(unsigned int)(MFD_ALL_FLAGS |
+ (MFD_HUGE_MASK << MFD_HUGE_SHIFT)))
+ return -EINVAL;
+ }
+
+ /* length includes terminating zero */
+ len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1);
+ if (len <= 0)
+ return -EFAULT;
+ if (len > MFD_NAME_MAX_LEN + 1)
+ return -EINVAL;
+
+ name = kmalloc(len + MFD_NAME_PREFIX_LEN, GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+
+ strcpy(name, MFD_NAME_PREFIX);
+ if (copy_from_user(&name[MFD_NAME_PREFIX_LEN], uname, len)) {
+ error = -EFAULT;
+ goto err_name;
+ }
+
+ /* terminating-zero may have changed after strnlen_user() returned */
+ if (name[len + MFD_NAME_PREFIX_LEN - 1]) {
+ error = -EFAULT;
+ goto err_name;
+ }
+
+ fd = get_unused_fd_flags((flags & MFD_CLOEXEC) ? O_CLOEXEC : 0);
+ if (fd < 0) {
+ error = fd;
+ goto err_name;
+ }
+
+ if (flags & MFD_HUGETLB) {
+ file = hugetlb_file_setup(name, 0, VM_NORESERVE,
+ HUGETLB_ANONHUGE_INODE,
+ (flags >> MFD_HUGE_SHIFT) &
+ MFD_HUGE_MASK);
+ } else
+ file = shmem_file_setup(name, 0, VM_NORESERVE);
+ if (IS_ERR(file)) {
+ error = PTR_ERR(file);
+ goto err_fd;
+ }
+ file->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
+ file->f_flags |= O_LARGEFILE;
+
+ if (flags & MFD_ALLOW_SEALING) {
+ file_seals = memfd_file_seals_ptr(file);
+ *file_seals &= ~F_SEAL_SEAL;
+ }
+
+ fd_install(fd, file);
+ kfree(name);
+ return fd;
+
+err_fd:
+ put_unused_fd(fd);
+err_name:
+ kfree(name);
+ return error;
+}