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    Subject[PATCH 4.19 107/293] ext4: report correct st_size for encrypted symlinks
    Date
    From: Eric Biggers <ebiggers@google.com>

    commit 8c4bca10ceafc43b1ca0a9fab5fa27e13cbce99e upstream.

    The stat() family of syscalls report the wrong size for encrypted
    symlinks, which has caused breakage in several userspace programs.

    Fix this by calling fscrypt_symlink_getattr() after ext4_getattr() for
    encrypted symlinks. This function computes the correct size by reading
    and decrypting the symlink target (if it's not already cached).

    For more details, see the commit which added fscrypt_symlink_getattr().

    Fixes: f348c252320b ("ext4 crypto: add symlink encryption")
    Cc: stable@vger.kernel.org
    Link: https://lore.kernel.org/r/20210702065350.209646-3-ebiggers@kernel.org
    Signed-off-by: Eric Biggers <ebiggers@google.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    fs/ext4/symlink.c | 11 ++++++++++-
    1 file changed, 10 insertions(+), 1 deletion(-)

    --- a/fs/ext4/symlink.c
    +++ b/fs/ext4/symlink.c
    @@ -52,10 +52,19 @@ static const char *ext4_encrypted_get_li
    return paddr;
    }

    +static int ext4_encrypted_symlink_getattr(const struct path *path,
    + struct kstat *stat, u32 request_mask,
    + unsigned int query_flags)
    +{
    + ext4_getattr(path, stat, request_mask, query_flags);
    +
    + return fscrypt_symlink_getattr(path, stat);
    +}
    +
    const struct inode_operations ext4_encrypted_symlink_inode_operations = {
    .get_link = ext4_encrypted_get_link,
    .setattr = ext4_setattr,
    - .getattr = ext4_getattr,
    + .getattr = ext4_encrypted_symlink_getattr,
    .listxattr = ext4_listxattr,
    };


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