Merge tag 'hardening-v6.8-rc1' of git://git.kernel.org/pub/scm/linux/…

…kernel/git/kees/linux

Pull hardening updates from Kees Cook:

 - Introduce the param_unknown_fn type and other clean ups (Andy
   Shevchenko)

 - Various __counted_by annotations (Christophe JAILLET, Gustavo A. R.
   Silva, Kees Cook)

 - Add KFENCE test to LKDTM (Stephen Boyd)

 - Various strncpy() refactorings (Justin Stitt)

 - Fix qnx4 to avoid writing into the smaller of two overlapping buffers

 - Various strlcpy() refactorings

* tag 'hardening-v6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  qnx4: Use get_directory_fname() in qnx4_match()
  qnx4: Extract dir entry filename processing into helper
  atags_proc: Add __counted_by for struct buffer and use struct_size()
  tracing/uprobe: Replace strlcpy() with strscpy()
  params: Fix multi-line comment style
  params: Sort headers
  params: Use size_add() for kmalloc()
  params: Do not go over the limit when getting the string length
  params: Introduce the param_unknown_fn type
  lkdtm: Add kfence read after free crash type
  nvme-fc: replace deprecated strncpy with strscpy
  nvdimm/btt: replace deprecated strncpy with strscpy
  nvme-fabrics: replace deprecated strncpy with strscpy
  drm/modes: replace deprecated strncpy with strscpy_pad
  afs: Add __counted_by for struct afs_acl and use struct_size()
  VMCI: Annotate struct vmci_handle_arr with __counted_by
  i40e: Annotate struct i40e_qvlist_info with __counted_by
  HID: uhid: replace deprecated strncpy with strscpy
  samples: Replace strlcpy() with strscpy()
  SUNRPC: Replace strlcpy() with strscpy()

arch/arm/kernel/atags_proc.c

@@ -7,7 +7,7 @@
 
 struct buffer {
 	size_t size;
-	char data[];
+	char data[] __counted_by(size);
 };
 
 static ssize_t atags_read(struct file *file, char __user *buf,
@@ -54,7 +54,7 @@ static int __init init_atags_procfs(void)
 
 	WARN_ON(tag->hdr.tag != ATAG_NONE);
 
-	b = kmalloc(sizeof(*b) + size, GFP_KERNEL);
+	b = kmalloc(struct_size(b, data, size), GFP_KERNEL);
 	if (!b)
 		goto nomem;
 

drivers/gpu/drm/drm_modes.c

@@ -2617,8 +2617,7 @@ void drm_mode_convert_to_umode(struct drm_mode_modeinfo *out,
 		break;
 	}
 
-	strncpy(out->name, in->name, DRM_DISPLAY_MODE_LEN);
-	out->name[DRM_DISPLAY_MODE_LEN-1] = 0;
+	strscpy_pad(out->name, in->name, sizeof(out->name));
 }
 
 /**
@@ -2659,8 +2658,7 @@ int drm_mode_convert_umode(struct drm_device *dev,
 	 * useful for the kernel->userspace direction anyway.
 	 */
 	out->type = in->type & DRM_MODE_TYPE_ALL;
-	strncpy(out->name, in->name, DRM_DISPLAY_MODE_LEN);
-	out->name[DRM_DISPLAY_MODE_LEN-1] = 0;
+	strscpy_pad(out->name, in->name, sizeof(out->name));
 
 	/* Clearing picture aspect ratio bits from out flags,
 	 * as the aspect-ratio information is not stored in

drivers/hid/uhid.c

@@ -490,7 +490,7 @@ static int uhid_dev_create2(struct uhid_device *uhid,
 			    const struct uhid_event *ev)
 {
 	struct hid_device *hid;
-	size_t rd_size, len;
+	size_t rd_size;
 	void *rd_data;
 	int ret;
 
@@ -514,13 +514,12 @@ static int uhid_dev_create2(struct uhid_device *uhid,
 		goto err_free;
 	}
 
-	/* @hid is zero-initialized, strncpy() is correct, strlcpy() not */
-	len = min(sizeof(hid->name), sizeof(ev->u.create2.name)) - 1;
-	strncpy(hid->name, ev->u.create2.name, len);
-	len = min(sizeof(hid->phys), sizeof(ev->u.create2.phys)) - 1;
-	strncpy(hid->phys, ev->u.create2.phys, len);
-	len = min(sizeof(hid->uniq), sizeof(ev->u.create2.uniq)) - 1;
-	strncpy(hid->uniq, ev->u.create2.uniq, len);
+	BUILD_BUG_ON(sizeof(hid->name) != sizeof(ev->u.create2.name));
+	strscpy(hid->name, ev->u.create2.name, sizeof(hid->name));
+	BUILD_BUG_ON(sizeof(hid->phys) != sizeof(ev->u.create2.phys));
+	strscpy(hid->phys, ev->u.create2.phys, sizeof(hid->phys));
+	BUILD_BUG_ON(sizeof(hid->uniq) != sizeof(ev->u.create2.uniq));
+	strscpy(hid->uniq, ev->u.create2.uniq, sizeof(hid->uniq));
 
 	hid->ll_driver = &uhid_hid_driver;
 	hid->bus = ev->u.create2.bus;

drivers/misc/lkdtm/heap.c

@@ -4,6 +4,7 @@
  * page allocation and slab allocations.
  */
 #include "lkdtm.h"
+#include <linux/kfence.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/sched.h>
@@ -132,6 +133,64 @@ static void lkdtm_READ_AFTER_FREE(void)
 	kfree(val);
 }
 
+static void lkdtm_KFENCE_READ_AFTER_FREE(void)
+{
+	int *base, val, saw;
+	unsigned long timeout, resched_after;
+	size_t len = 1024;
+	/*
+	 * The slub allocator will use the either the first word or
+	 * the middle of the allocation to store the free pointer,
+	 * depending on configurations. Store in the second word to
+	 * avoid running into the freelist.
+	 */
+	size_t offset = sizeof(*base);
+
+	/*
+	 * 100x the sample interval should be more than enough to ensure we get
+	 * a KFENCE allocation eventually.
+	 */
+	timeout = jiffies + msecs_to_jiffies(100 * kfence_sample_interval);
+	/*
+	 * Especially for non-preemption kernels, ensure the allocation-gate
+	 * timer can catch up: after @resched_after, every failed allocation
+	 * attempt yields, to ensure the allocation-gate timer is scheduled.
+	 */
+	resched_after = jiffies + msecs_to_jiffies(kfence_sample_interval);
+	do {
+		base = kmalloc(len, GFP_KERNEL);
+		if (!base) {
+			pr_err("FAIL: Unable to allocate kfence memory!\n");
+			return;
+		}
+
+		if (is_kfence_address(base)) {
+			val = 0x12345678;
+			base[offset] = val;
+			pr_info("Value in memory before free: %x\n", base[offset]);
+
+			kfree(base);
+
+			pr_info("Attempting bad read from freed memory\n");
+			saw = base[offset];
+			if (saw != val) {
+				/* Good! Poisoning happened, so declare a win. */
+				pr_info("Memory correctly poisoned (%x)\n", saw);
+			} else {
+				pr_err("FAIL: Memory was not poisoned!\n");
+				pr_expected_config_param(CONFIG_INIT_ON_FREE_DEFAULT_ON, "init_on_free");
+			}
+			return;
+		}
+
+		kfree(base);
+		if (time_after(jiffies, resched_after))
+			cond_resched();
+	} while (time_before(jiffies, timeout));
+
+	pr_err("FAIL: kfence memory never allocated!\n");
+}
+
 static void lkdtm_WRITE_BUDDY_AFTER_FREE(void)
 {
 	unsigned long p = __get_free_page(GFP_KERNEL);
@@ -327,6 +386,7 @@ static struct crashtype crashtypes[] = {
 	CRASHTYPE(VMALLOC_LINEAR_OVERFLOW),
 	CRASHTYPE(WRITE_AFTER_FREE),
 	CRASHTYPE(READ_AFTER_FREE),
+	CRASHTYPE(KFENCE_READ_AFTER_FREE),
 	CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
 	CRASHTYPE(READ_BUDDY_AFTER_FREE),
 	CRASHTYPE(SLAB_INIT_ON_ALLOC),

drivers/misc/vmw_vmci/vmci_handle_array.h

@@ -17,7 +17,7 @@ struct vmci_handle_arr {
 	u32 max_capacity;
 	u32 size;
 	u32 pad;
-	struct vmci_handle entries[];
+	struct vmci_handle entries[] __counted_by(capacity);
 };
 
 #define VMCI_HANDLE_ARRAY_HEADER_SIZE				\

drivers/nvdimm/btt.c

@@ -986,7 +986,7 @@ static int btt_arena_write_layout(struct arena_info *arena)
 	if (!super)
 		return -ENOMEM;
 
-	strncpy(super->signature, BTT_SIG, BTT_SIG_LEN);
+	strscpy(super->signature, BTT_SIG, sizeof(super->signature));
 	export_uuid(super->uuid, nd_btt->uuid);
 	export_uuid(super->parent_uuid, parent_uuid);
 	super->flags = cpu_to_le32(arena->flags);

drivers/nvme/host/fabrics.c

@@ -387,8 +387,8 @@ static struct nvmf_connect_data *nvmf_connect_data_prep(struct nvme_ctrl *ctrl,
 
 	uuid_copy(&data->hostid, &ctrl->opts->host->id);
 	data->cntlid = cpu_to_le16(cntlid);
-	strncpy(data->subsysnqn, ctrl->opts->subsysnqn, NVMF_NQN_SIZE);
-	strncpy(data->hostnqn, ctrl->opts->host->nqn, NVMF_NQN_SIZE);
+	strscpy(data->subsysnqn, ctrl->opts->subsysnqn, NVMF_NQN_SIZE);
+	strscpy(data->hostnqn, ctrl->opts->host->nqn, NVMF_NQN_SIZE);
 
 	return data;
 }

drivers/nvme/host/fc.c

@@ -1218,10 +1218,10 @@ nvme_fc_connect_admin_queue(struct nvme_fc_ctrl *ctrl,
 	/* Linux supports only Dynamic controllers */
 	assoc_rqst->assoc_cmd.cntlid = cpu_to_be16(0xffff);
 	uuid_copy(&assoc_rqst->assoc_cmd.hostid, &ctrl->ctrl.opts->host->id);
-	strncpy(assoc_rqst->assoc_cmd.hostnqn, ctrl->ctrl.opts->host->nqn,
-		min(FCNVME_ASSOC_HOSTNQN_LEN, NVMF_NQN_SIZE));
-	strncpy(assoc_rqst->assoc_cmd.subnqn, ctrl->ctrl.opts->subsysnqn,
-		min(FCNVME_ASSOC_SUBNQN_LEN, NVMF_NQN_SIZE));
+	strscpy(assoc_rqst->assoc_cmd.hostnqn, ctrl->ctrl.opts->host->nqn,
+		sizeof(assoc_rqst->assoc_cmd.hostnqn));
+	strscpy(assoc_rqst->assoc_cmd.subnqn, ctrl->ctrl.opts->subsysnqn,
+		sizeof(assoc_rqst->assoc_cmd.subnqn));
 
 	lsop->queue = queue;
 	lsreq->rqstaddr = assoc_rqst;

fs/afs/internal.h

@@ -1213,7 +1213,7 @@ extern void afs_fs_inline_bulk_status(struct afs_operation *);
 
 struct afs_acl {
 	u32	size;
-	u8	data[];
+	u8	data[] __counted_by(size);
 };
 
 extern void afs_fs_fetch_acl(struct afs_operation *);

fs/afs/xattr.c

@@ -75,7 +75,7 @@ static bool afs_make_acl(struct afs_operation *op,
 {
 	struct afs_acl *acl;
 
-	acl = kmalloc(sizeof(*acl) + size, GFP_KERNEL);
+	acl = kmalloc(struct_size(acl, data, size), GFP_KERNEL);
 	if (!acl) {
 		afs_op_nomem(op);
 		return false;

fs/qnx4/dir.c

@@ -15,43 +15,6 @@
 #include <linux/buffer_head.h>
 #include "qnx4.h"
 
-/*
- * A qnx4 directory entry is an inode entry or link info
- * depending on the status field in the last byte. The
- * first byte is where the name start either way, and a
- * zero means it's empty.
- *
- * Also, due to a bug in gcc, we don't want to use the
- * real (differently sized) name arrays in the inode and
- * link entries, but always the 'de_name[]' one in the
- * fake struct entry.
- *
- * See
- *
- *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6
- *
- * for details, but basically gcc will take the size of the
- * 'name' array from one of the used union entries randomly.
- *
- * This use of 'de_name[]' (48 bytes) avoids the false positive
- * warnings that would happen if gcc decides to use 'inode.di_name'
- * (16 bytes) even when the pointer and size were to come from
- * 'link.dl_name' (48 bytes).
- *
- * In all cases the actual name pointer itself is the same, it's
- * only the gcc internal 'what is the size of this field' logic
- * that can get confused.
- */
-union qnx4_directory_entry {
-	struct {
-		const char de_name[48];
-		u8 de_pad[15];
-		u8 de_status;
-	};
-	struct qnx4_inode_entry inode;
-	struct qnx4_link_info link;
-};
-
 static int qnx4_readdir(struct file *file, struct dir_context *ctx)
 {
 	struct inode *inode = file_inode(file);
@@ -74,26 +37,25 @@ static int qnx4_readdir(struct file *file, struct dir_context *ctx)
 		ix = (ctx->pos >> QNX4_DIR_ENTRY_SIZE_BITS) % QNX4_INODES_PER_BLOCK;
 		for (; ix < QNX4_INODES_PER_BLOCK; ix++, ctx->pos += QNX4_DIR_ENTRY_SIZE) {
 			union qnx4_directory_entry *de;
+			const char *fname;
 
 			offset = ix * QNX4_DIR_ENTRY_SIZE;
 			de = (union qnx4_directory_entry *) (bh->b_data + offset);
 
-			if (!de->de_name[0])
-				continue;
-			if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK)))
+			fname = get_entry_fname(de, &size);
+			if (!fname)
 				continue;
+
 			if (!(de->de_status & QNX4_FILE_LINK)) {
-				size = sizeof(de->inode.di_fname);
 				ino = blknum * QNX4_INODES_PER_BLOCK + ix - 1;
 			} else {
-				size = sizeof(de->link.dl_fname);
 				ino = ( le32_to_cpu(de->link.dl_inode_blk) - 1 ) *
 					QNX4_INODES_PER_BLOCK +
 					de->link.dl_inode_ndx;
 			}
-			size = strnlen(de->de_name, size);
-			QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, name));
-			if (!dir_emit(ctx, de->de_name, size, ino, DT_UNKNOWN)) {
+
+			QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, fname));
+			if (!dir_emit(ctx, fname, size, ino, DT_UNKNOWN)) {
 				brelse(bh);
 				return 0;
 			}

fs/qnx4/namei.c

@@ -26,31 +26,24 @@
 static int qnx4_match(int len, const char *name,
 		      struct buffer_head *bh, unsigned long *offset)
 {
-	struct qnx4_inode_entry *de;
-	int namelen, thislen;
+	union qnx4_directory_entry *de;
+	const char *fname;
+	int fnamelen;
 
 	if (bh == NULL) {
 		printk(KERN_WARNING "qnx4: matching unassigned buffer !\n");
 		return 0;
 	}
-	de = (struct qnx4_inode_entry *) (bh->b_data + *offset);
+	de = (union qnx4_directory_entry *) (bh->b_data + *offset);
 	*offset += QNX4_DIR_ENTRY_SIZE;
-	if ((de->di_status & QNX4_FILE_LINK) != 0) {
-		namelen = QNX4_NAME_MAX;
-	} else {
-		namelen = QNX4_SHORT_NAME_MAX;
-	}
-	thislen = strlen( de->di_fname );
-	if ( thislen > namelen )
-		thislen = namelen;
-	if (len != thislen) {
+
+	fname = get_entry_fname(de, &fnamelen);
+	if (!fname || len != fnamelen)
 		return 0;
-	}
-	if (strncmp(name, de->di_fname, len) == 0) {
-		if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) {
-			return 1;
-		}
-	}
+
+	if (strncmp(name, fname, len) == 0)
+		return 1;
+
 	return 0;
 }
 

fs/qnx4/qnx4.h

@@ -44,3 +44,63 @@ static inline struct qnx4_inode_entry *qnx4_raw_inode(struct inode *inode)
 {
 	return &qnx4_i(inode)->raw;
 }
+
+/*
+ * A qnx4 directory entry is an inode entry or link info
+ * depending on the status field in the last byte. The
+ * first byte is where the name start either way, and a
+ * zero means it's empty.
+ *
+ * Also, due to a bug in gcc, we don't want to use the
+ * real (differently sized) name arrays in the inode and
+ * link entries, but always the 'de_name[]' one in the
+ * fake struct entry.
+ *
+ * See
+ *
+ *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6
+ *
+ * for details, but basically gcc will take the size of the
+ * 'name' array from one of the used union entries randomly.
+ *
+ * This use of 'de_name[]' (48 bytes) avoids the false positive
+ * warnings that would happen if gcc decides to use 'inode.di_name'
+ * (16 bytes) even when the pointer and size were to come from
+ * 'link.dl_name' (48 bytes).
+ *
+ * In all cases the actual name pointer itself is the same, it's
+ * only the gcc internal 'what is the size of this field' logic
+ * that can get confused.
+ */
+union qnx4_directory_entry {
+	struct {
+		const char de_name[48];
+		u8 de_pad[15];
+		u8 de_status;
+	};
+	struct qnx4_inode_entry inode;
+	struct qnx4_link_info link;
+};
+
+static inline const char *get_entry_fname(union qnx4_directory_entry *de,
+					  int *size)
+{
+	/* Make sure the status byte is in the same place for all structs. */
+	BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
+			offsetof(struct qnx4_link_info, dl_status));
+	BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
+			offsetof(union qnx4_directory_entry, de_status));
+
+	if (!de->de_name[0])
+		return NULL;
+	if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK)))
+		return NULL;
+	if (!(de->de_status & QNX4_FILE_LINK))
+		*size = sizeof(de->inode.di_fname);
+	else
+		*size = sizeof(de->link.dl_fname);
+
+	*size = strnlen(de->de_name, *size);
+
+	return de->de_name;
+}