Commit cb3ae6d2 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

fuse: listxattr: verify xattr list



Make sure userspace filesystem is returning a well formed list of xattr
names (zero or more nonzero length, null terminated strings).

[Michael Theall: only verify in the nonzero size case]
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org>
parent 08895a8b
......@@ -1801,6 +1801,23 @@ static ssize_t fuse_getxattr(struct dentry *entry, struct inode *inode,
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;
}
static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
{
struct inode *inode = d_inode(entry);
......@@ -1836,6 +1853,8 @@ static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
ret = fuse_simple_request(fc, &args);
if (!ret && !size)
ret = outarg.size;
if (ret > 0 && size)
ret = fuse_verify_xattr_list(list, ret);
if (ret == -ENOSYS) {
fc->no_listxattr = 1;
ret = -EOPNOTSUPP;
......
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