From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793828872; b=bOFvsXdEXCBUQ5H487I3nFhyKDVXZigBmJlqFZfBvbRQDR4nt95s2tDF7ZQDZpqTodFx IiDohdANrEGiYAwf7prJs5/5FKCox8ZJjCzwP1arq8PkyIQTkOUoTmLSULQax7e3OjIwA +xkHDgUUYX6sfxK7bTOgYgDw9aqZ4Dr6KN8l4+fty8NPvjKUiOOeS2yo9vU6sfhXZTEbJ 9zyUyArIn5svmi0fB+0RY53e3wFMpT5Kuv4qXDlAu6btujy2NcRjxyfEgpV9Lb28spsLM 4W1tPzmtmHhsao6l3o2YPA7edynX/vpQTTn04A1q00wRlLXspqoPH4FgTC8MRYpYP0A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793828872; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=HRhSnRD0JBn0vGpivJUaT0Htgfgu4+IX+ANUKcNGOZQ=; b=Tlb4k6Gb56LuHZktlOP2b7ADHNLvIj/XQ+S6ylPmx25dutevQp4dZkt3mgvxGrd95Cc5 ZngWdnMRN/xoB2E++Ugm69hPAxjFjq9WZtkEt7hVwUOs21wmftYf78b+P+81qnvrZEFDf cAknoat/H58dzHoMYaWTGOdSxzFmSjpOByUL4NEEZhRRTwidEwjskcTjqb/JUXXotzheO 7LHmaFF0cK1GgYVFpv/KT9yTZOkUyaL6KatOT9doknPme7MVrOUdkTNjK44bv08vlgEGK Wu45rgWhFM0gK3NLGnQEMXuFTNJ3kfs7YHVeIKL0uJ+s9RaWZCfue7SZ2vCyzuJHJgg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ASrKR6Lk; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 66F5B6070F39; Wed, 4 Nov 2026 21:47:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ASrKR6Lk Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08D131F00919; Wed, 4 Nov 2026 21:47:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793828872; bh=HRhSnRD0JBn0vGpivJUaT0Htgfgu4+IX+ANUKcNGOZQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ASrKR6Lk6EhcKdZ4BsqIrXN2R5ioqTLrVvlcp8aT8dO+tJ5HBL2zP8d+x2Uwkn67z fUYMEtrGHDoftlif6URCGdcEwJVGemfis9Tn4djgYJRN4kRzEIVxLv9RpCtOdME8Hy ZT7BvTWz0u6Msvkbp3ZaW+vJvl7buYAplz7kk5us= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fahad Alharbi , Miklos Szeredi , Amir Goldstein Subject: [PATCH 7.3 293/547] ovl: fortify ovl_copy_xattr() against underlying layer modifications Date: Wed, 4 Nov 2026 16:07:57 -0500 Message-ID: <20261104211046.528525391@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211038.406938024@linuxfoundation.org> References: <20261104211038.406938024@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Amir Goldstein commit e6b9117076fb4c0ff4a670efa9c876d9a50d79ab upstream. Adapt ovl_getxattr_value() to be used from ovl_copy_xattr(), by allowing to pass it a pre-allocated buffer, which can be resized and by handling the ENODATA/EOPNOTSUPP return codes in the caller. This replaces the retry loop in ovl_copy_xattr() with a single retry after resizing the buffer. If the value changed again by then, the underlying layer was modified, so return -EIO instead of retrying. As a side effect, ovl_copy_up_meta_inode_data() now returns -EIO instead of -ERANGE in this case of underlying xattr size changes. Reported-by: Fahad Alharbi Tested-by: Fahad Alharbi Suggested-by: Miklos Szeredi Link: https://lore.kernel.org/linux-fsdevel/CAJfpegsVoUyqy0dYkTvBGRZvgdv_nmzmCw_uF+LP-Vq3EhEkSg@mail.gmail.com/ Fixes: e4ad29fa0d22 ("ovl: use a minimal buffer in ovl_copy_xattr") Cc: stable@vger.kernel.org Signed-off-by: Amir Goldstein Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/copy_up.c | 68 +++++++++++++++++++++++-------------------------- 1 file changed, 32 insertions(+), 36 deletions(-) --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -72,6 +72,9 @@ static int ovl_copy_acl(struct ovl_fs *o return err; } +static ssize_t ovl_getxattr_value(const struct path *path, char *name, + char **value, ssize_t *value_size); + int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct dentry *new) { struct dentry *old = oldpath->dentry; @@ -129,34 +132,12 @@ int ovl_copy_xattr(struct super_block *s break; } -retry: - size = ovl_do_getxattr(oldpath, name, value, value_size); - if (size == -ERANGE) { - size = ovl_do_getxattr(oldpath, name, NULL, 0); - /* Nothing was read into value, so it must not be used */ - if (size >= 0 && size <= value_size) - size = -EIO; - } - + size = ovl_getxattr_value(oldpath, name, &value, &value_size); if (size < 0) { error = size; break; } - if (size > value_size) { - void *new; - - new = kvmalloc(size, GFP_KERNEL); - if (!new) { - error = -ENOMEM; - break; - } - kvfree(value); - value = new; - value_size = size; - goto retry; - } - error = ovl_do_setxattr(OVL_FS(sb), new, name, value, size, 0); if (error) { if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name)) @@ -1070,26 +1051,39 @@ static bool ovl_need_meta_copy_up(struct return true; } -static ssize_t ovl_getxattr_value(const struct path *path, char *name, char **value) +static ssize_t ovl_getxattr_value(const struct path *path, char *name, + char **value, ssize_t *value_size) { ssize_t res; char *buf; - res = ovl_do_getxattr(path, name, NULL, 0); - if (res == -ENODATA || res == -EOPNOTSUPP) - res = 0; + res = ovl_do_getxattr(path, name, *value, *value_size); + if (res == -ERANGE) { + res = ovl_do_getxattr(path, name, NULL, 0); + /* Xattr changed underneath us? */ + if (res >= 0 && res <= *value_size) + return -EIO; + } - if (res > 0) { - buf = kzalloc(res, GFP_KERNEL); + if (res > *value_size) { + buf = kvmalloc(res, GFP_KERNEL); if (!buf) return -ENOMEM; res = ovl_do_getxattr(path, name, buf, res); - if (res < 0) - kfree(buf); - else - *value = buf; + if (res < 0) { + kvfree(buf); + /* Xattr changed underneath us? */ + if (res == -ERANGE) + return -EIO; + return res; + } + + kvfree(*value); + *value = buf; + *value_size = res; } + return res; } @@ -1100,7 +1094,7 @@ static int ovl_copy_up_meta_inode_data(s struct path upperpath; int err; char *capability = NULL; - ssize_t cap_size; + ssize_t cap_size = 0; ovl_path_upper(c->dentry, &upperpath); if (WARN_ON(upperpath.dentry == NULL)) @@ -1108,7 +1102,9 @@ static int ovl_copy_up_meta_inode_data(s if (c->stat.size) { err = cap_size = ovl_getxattr_value(&upperpath, XATTR_NAME_CAPS, - &capability); + &capability, &cap_size); + if (cap_size == -ENODATA || cap_size == -EOPNOTSUPP) + cap_size = 0; if (cap_size < 0) goto out; } @@ -1138,7 +1134,7 @@ static int ovl_copy_up_meta_inode_data(s ovl_clear_flag(OVL_VERIFIED_DIGEST, d_inode(c->dentry)); ovl_set_upperdata(d_inode(c->dentry)); out_free: - kfree(capability); + kvfree(capability); out: return err; }