staging: rtl8723bs: fix OOB read in rtw_action_frame_parse()grafted

rtw_action_frame_parse() takes a frame_len parameter but never
actually checks it before indexing into the frame body:

	const u8 *frame_body = frame + sizeof(struct ieee80211_hdr_3addr);
	...
	c = frame_body[0];
	...
	a = frame_body[1];

frame_body already points 24 bytes (sizeof(struct
ieee80211_hdr_3addr)) into frame, so reading frame_body[0] and
frame_body[1] requires frame_len >= 26. A management action frame
shorter than that (e.g. exactly 24 bytes, the minimum a malicious
peer can send) causes a 1-2 byte out-of-bounds read.

This is reachable from rtw_cfg80211_monitor_if_xmit_entry() and
cfg80211_rtw_mgmt_tx() in ioctl_cfg80211.c, both of which pass
attacker/user-influenced frame buffers and lengths straight through.

Add the missing length check before frame_body is dereferenced.

Fixes: 554c0a3abf216 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
Link: https://patch.msgid.link/20260728125456.32359-3-meatuni001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 214 insertions, 0 deletions

diff --git a/fs/fuse/xattr.c b/fs/fuse/xattr.c
new file mode 100644
index 000000000..cab2685ac
--- /dev/null
+++ b/fs/fuse/xattr.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * FUSE: Filesystem in Userspace
+ * Copyright (C) 2001-2016  Miklos Szeredi <miklos@szeredi.hu>
+ */
+
+#include "fuse_i.h"
+
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+
+int fuse_setxattr(struct inode *inode, const char *name, const void *value,
+		  size_t size, int flags, unsigned int extra_flags)
+{
+	struct fuse_mount *fm = get_fuse_mount(inode);
+	FUSE_ARGS(args);
+	struct fuse_setxattr_in inarg;
+	int err;
+
+	if (fm->fc->no_setxattr)
+		return -EOPNOTSUPP;
+
+	memset(&inarg, 0, sizeof(inarg));
+	inarg.size = size;
+	inarg.flags = flags;
+	inarg.setxattr_flags = extra_flags;
+
+	args.opcode = FUSE_SETXATTR;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 3;
+	args.in_args[0].size = fm->fc->setxattr_ext ?
+		sizeof(inarg) : FUSE_COMPAT_SETXATTR_IN_SIZE;
+	args.in_args[0].value = &inarg;
+	args.in_args[1].size = strlen(name) + 1;
+	args.in_args[1].value = name;
+	args.in_args[2].size = size;
+	args.in_args[2].value = value;
+	err = fuse_simple_request(fm, &args);
+	if (err == -ENOSYS) {
+		fm->fc->no_setxattr = 1;
+		err = -EOPNOTSUPP;
+	}
+	if (!err)
+		fuse_update_ctime(inode);
+
+	return err;
+}
+
+ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
+		      size_t size)
+{
+	struct fuse_mount *fm = get_fuse_mount(inode);
+	FUSE_ARGS(args);
+	struct fuse_getxattr_in inarg;
+	struct fuse_getxattr_out outarg;
+	ssize_t ret;
+
+	if (fm->fc->no_getxattr)
+		return -EOPNOTSUPP;
+
+	memset(&inarg, 0, sizeof(inarg));
+	inarg.size = size;
+	args.opcode = FUSE_GETXATTR;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 2;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	args.in_args[1].size = strlen(name) + 1;
+	args.in_args[1].value = name;
+	/* This is really two different operations rolled into one */
+	args.out_numargs = 1;
+	if (size) {
+		args.out_argvar = true;
+		args.out_args[0].size = size;
+		args.out_args[0].value = value;
+	} else {
+		args.out_args[0].size = sizeof(outarg);
+		args.out_args[0].value = &outarg;
+	}
+	ret = fuse_simple_request(fm, &args);
+	if (!ret && !size)
+		ret = min_t(size_t, outarg.size, XATTR_SIZE_MAX);
+	if (ret == -ENOSYS) {
+		fm->fc->no_getxattr = 1;
+		ret = -EOPNOTSUPP;
+	}
+	return ret;
+}
+
+static int fuse_verify_xattr_list(char *list, size_t size)
+{
+	size_t origsize = size;
+
+	while (size) {
+		size_t thislen = strnlen(list, size);
+
+		if (!thislen || thislen == size)
+			return -EIO;
+
+		size -= thislen + 1;
+		list += thislen + 1;
+	}
+
+	return origsize;
+}
+
+ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
+{
+	struct inode *inode = d_inode(entry);
+	struct fuse_mount *fm = get_fuse_mount(inode);
+	FUSE_ARGS(args);
+	struct fuse_getxattr_in inarg;
+	struct fuse_getxattr_out outarg;
+	ssize_t ret;
+
+	if (fuse_is_bad(inode))
+		return -EIO;
+
+	if (!fuse_allow_current_process(fm->fc))
+		return -EACCES;
+
+	if (fm->fc->no_listxattr)
+		return -EOPNOTSUPP;
+
+	memset(&inarg, 0, sizeof(inarg));
+	inarg.size = size;
+	args.opcode = FUSE_LISTXATTR;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	/* This is really two different operations rolled into one */
+	args.out_numargs = 1;
+	if (size) {
+		args.out_argvar = true;
+		args.out_args[0].size = size;
+		args.out_args[0].value = list;
+	} else {
+		args.out_args[0].size = sizeof(outarg);
+		args.out_args[0].value = &outarg;
+	}
+	ret = fuse_simple_request(fm, &args);
+	if (!ret && !size)
+		ret = min_t(size_t, outarg.size, XATTR_LIST_MAX);
+	if (ret > 0 && size)
+		ret = fuse_verify_xattr_list(list, ret);
+	if (ret == -ENOSYS) {
+		fm->fc->no_listxattr = 1;
+		ret = -EOPNOTSUPP;
+	}
+	return ret;
+}
+
+int fuse_removexattr(struct inode *inode, const char *name)
+{
+	struct fuse_mount *fm = get_fuse_mount(inode);
+	FUSE_ARGS(args);
+	int err;
+
+	if (fm->fc->no_removexattr)
+		return -EOPNOTSUPP;
+
+	args.opcode = FUSE_REMOVEXATTR;
+	args.nodeid = get_node_id(inode);
+	args.in_numargs = 2;
+	fuse_set_zero_arg0(&args);
+	args.in_args[1].size = strlen(name) + 1;
+	args.in_args[1].value = name;
+	err = fuse_simple_request(fm, &args);
+	if (err == -ENOSYS) {
+		fm->fc->no_removexattr = 1;
+		err = -EOPNOTSUPP;
+	}
+	if (!err)
+		fuse_update_ctime(inode);
+
+	return err;
+}
+
+static int fuse_xattr_get(const struct xattr_handler *handler,
+			 struct dentry *dentry, struct inode *inode,
+			 const char *name, void *value, size_t size)
+{
+	if (fuse_is_bad(inode))
+		return -EIO;
+
+	return fuse_getxattr(inode, name, value, size);
+}
+
+static int fuse_xattr_set(const struct xattr_handler *handler,
+			  struct mnt_idmap *idmap,
+			  struct dentry *dentry, struct inode *inode,
+			  const char *name, const void *value, size_t size,
+			  int flags)
+{
+	if (fuse_is_bad(inode))
+		return -EIO;
+
+	if (!value)
+		return fuse_removexattr(inode, name);
+
+	return fuse_setxattr(inode, name, value, size, flags, 0);
+}
+
+static const struct xattr_handler fuse_xattr_handler = {
+	.prefix = "",
+	.get    = fuse_xattr_get,
+	.set    = fuse_xattr_set,
+};
+
+const struct xattr_handler * const fuse_xattr_handlers[] = {
+	&fuse_xattr_handler,
+	NULL
+};