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 11BCC3563D4; Fri, 24 Apr 2026 13:42:31 +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=1777038151; cv=none; b=RX4ECZS+nR0pwBOGKcO8L7WlbaOtRDyJWLD8T2X4L91Ejp6I6Mn8enohpwQnfYyHMKbYAnoqDY+PIe6+qQhKC1WFQHRvWsRJ6LIB1BMnxByhLqQIamafGxTI7CIFS09NoVpuhT1uoA8rYxscLkSD48KOvBthrbgatCchRgrHwBo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777038151; c=relaxed/simple; bh=hHYTfZQzCOZfTiA3ksb39R2BniL1jhsQrdTQzguakNA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lJKSQg2ZcSQygzOiA0LUEb9YWJZ1XpFRQS3/OGf3Xx/l9QWjOUQCiX4zS0ZX7HjEOWQKO3TmCBIZBEJ8iIZ3NDLxO6Gg7kD2oVzmuCbqLtpFwXMtjKx8AyVpQoWGmp0r8G0QBEL9wRwiejwfrd4FnfvxnUHUduDoFmVqcLmPb4g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lYFzmsS6; 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="lYFzmsS6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C7D1C19425; Fri, 24 Apr 2026 13:42:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777038151; bh=hHYTfZQzCOZfTiA3ksb39R2BniL1jhsQrdTQzguakNA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lYFzmsS6U/cvqUMsY8bs6NQP01enFKWq9NQ3qqbq3w0LyKB3Y3FuilJW14PDHBIv3 PnPRCIKEiQQmWa1lAc/sNLepaV/lnjQjNoCkk9ypDJjcvQ6XJZcWOdGxGfDXi9j/rb 0KNsh/chACOjmf36Sm1nGY5a12EwUb6x4fIrREpY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tristan Madani , Namjae Jeon , Steve French Subject: [PATCH 6.18 43/55] ksmbd: fix out-of-bounds write in smb2_get_ea() EA alignment Date: Fri, 24 Apr 2026 15:31:22 +0200 Message-ID: <20260424132438.973010750@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260424132430.006424517@linuxfoundation.org> References: <20260424132430.006424517@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tristan Madani commit 30010c952077a1c89ecdd71fc4d574c75a8f5617 upstream. smb2_get_ea() applies 4-byte alignment padding via memset() after writing each EA entry. The bounds check on buf_free_len is performed before the value memcpy, but the alignment memset fires unconditionally afterward with no check on remaining space. When the EA value exactly fills the remaining buffer (buf_free_len == 0 after value subtraction), the alignment memset writes 1-3 NUL bytes past the buf_free_len boundary. In compound requests where the response buffer is shared across commands, the first command (e.g., READ) can consume most of the buffer, leaving a tight remainder for the QUERY_INFO EA response. The alignment memset then overwrites past the physical kvmalloc allocation into adjacent kernel heap memory. Add a bounds check before the alignment memset to ensure buf_free_len can accommodate the padding bytes. This is the same bug pattern fixed by commit beef2634f81f ("ksmbd: fix potencial OOB in get_file_all_info() for compound requests") and commit fda9522ed6af ("ksmbd: fix OOB write in QUERY_INFO for compound requests"), both of which added bounds checks before unconditional writes in QUERY_INFO response handlers. Cc: stable@vger.kernel.org Fixes: e2b76ab8b5c9 ("ksmbd: add support for read compound") Signed-off-by: Tristan Madani Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/server/smb2pdu.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -4831,6 +4831,8 @@ static int smb2_get_ea(struct ksmbd_work /* align next xattr entry at 4 byte bundary */ alignment_bytes = ((next_offset + 3) & ~3) - next_offset; if (alignment_bytes) { + if (buf_free_len < alignment_bytes) + break; memset(ptr, '\0', alignment_bytes); ptr += alignment_bytes; next_offset += alignment_bytes;