4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
commit cb3ae6d25a5471be62bfe6ac1fccc0e91edeaba0 upstream.
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: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/fuse/dir.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1797,6 +1797,23 @@ static ssize_t fuse_getxattr(struct dent
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);
@@ -1832,6 +1849,8 @@ static ssize_t fuse_listxattr(struct den
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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