From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 292EF3EDE5C; Tue, 12 May 2026 18:09:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778609386; cv=none; b=kSfLtia+KxMsc4tCPtvqBRlDeCWHp9I9BFI/60zm+QAo7echXca+zNbNG40oUH0b0aMF+EN7mUZuwwUom4oee12ibFzgseh3saPAJpn7oGXcqk3Hlsd4+zRT/DmKkDZ6ll0N5sRZNJdTNxxJpe/XWGY7QIi/+40p9agtmzC66Iw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778609386; c=relaxed/simple; bh=gJ3OEAeLq7KCFHN3CmR2gEqUIYpeo2UOjGbCd5jnsWE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=p0gggOLFBqzlqhRbOisACjYy6Yfj1UfphFa75dpGqIGd97fuHVPOiKuxjxSSY7PYHYCTKuFcIq7qhj2Tf7C1rJ/xBlzk859a25zy06bTR916TRvv+atsTcut7tjIcMQyzQ5Pr9mWjNAO+cAjy5j8psQFcemkb9HtqNWKPPkKHsE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PFw7oZhk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PFw7oZhk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B454FC2BCB0; Tue, 12 May 2026 18:09:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778609386; bh=gJ3OEAeLq7KCFHN3CmR2gEqUIYpeo2UOjGbCd5jnsWE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PFw7oZhks9eqT3ECmdl+qtC6oyuOxEsnMK5Mc7BAAljohsWSk8kD01CfGE7XJz8g8 bLwpzB9Z1U3bVl8iy4Zo05THmtYlFqRzIsL/j76FuvnyQewaEa2vccj62ez7OHkzxD bbz5q98IHMh12nBO4AgQyP4cGXx7acaRDIJ8vcXo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yochai Eisenrich , David Sterba Subject: [PATCH 7.0 176/307] btrfs: fix btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak Date: Tue, 12 May 2026 19:39:31 +0200 Message-ID: <20260512173943.831820710@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260512173940.117428952@linuxfoundation.org> References: <20260512173940.117428952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yochai Eisenrich commit 973e57c726c1f8e77259d1c8e519519f1e9aea77 upstream. btrfs_ioctl_space_info() has a TOCTOU race between two passes over the block group RAID type lists. The first pass counts entries to determine the allocation size, then the second pass fills the buffer. The groups_sem rwlock is released between passes, allowing concurrent block group removal to reduce the entry count. When the second pass fills fewer entries than the first pass counted, copy_to_user() copies the full alloc_size bytes including trailing uninitialized kmalloc bytes to userspace. Fix by copying only total_spaces entries (the actually-filled count from the second pass) instead of alloc_size bytes, and switch to kzalloc so any future copy size mismatch cannot leak heap data. Fixes: 7fde62bffb57 ("Btrfs: buffer results in the space_info ioctl") CC: stable@vger.kernel.org # 3.0 Signed-off-by: Yochai Eisenrich Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/ioctl.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2897,7 +2897,7 @@ static long btrfs_ioctl_space_info(struc return -ENOMEM; space_args.total_spaces = 0; - dest = kmalloc(alloc_size, GFP_KERNEL); + dest = kzalloc(alloc_size, GFP_KERNEL); if (!dest) return -ENOMEM; dest_orig = dest; @@ -2953,7 +2953,8 @@ static long btrfs_ioctl_space_info(struc user_dest = (struct btrfs_ioctl_space_info __user *) (arg + sizeof(struct btrfs_ioctl_space_args)); - if (copy_to_user(user_dest, dest_orig, alloc_size)) + if (copy_to_user(user_dest, dest_orig, + space_args.total_spaces * sizeof(*dest_orig))) return -EFAULT; out: