ext4: ignore e_value_offs for xattrs with value-in-ea-inode

In other places in fs/ext4/xattr.c, if e_value_inum is non-zero, the
code ignores the value in e_value_offs.  The e_value_offs *should* be
zero, but we shouldn't depend upon it, since it might not be true in a
corrupted/fuzzed file system.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202897
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202877
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index dc82e77..491f9ee 100644 (file)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1696,7 +1696,7 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
 
        /* No failures allowed past this point. */
 
-       if (!s->not_found && here->e_value_size && here->e_value_offs) {
+       if (!s->not_found && here->e_value_size && !here->e_value_inum) {
                /* Remove the old value. */
                void *first_val = s->base + min_offs;
                size_t offs = le16_to_cpu(here->e_value_offs);