From 38643d20b4d4ac378046e51b15556f0f7dc489ea Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Mon, 19 Mar 2018 14:07:45 +0300 Subject: [PATCH] staging: ncpfs: memory corruption in ncp_read_kernel() commit 4c41aa24baa4ed338241d05494f2c595c885af8f upstream. If the server is malicious then *bytes_read could be larger than the size of the "target" buffer. It would lead to memory corruption when we do the memcpy(). Reported-by: Dr Silvio Cesare of InfoSect Signed-off-by: Dan Carpenter Signed-off-by: Greg Kroah-Hartman [carnil: backport to 4.9: Files renamed from drivers/staging/ncpfs/ncplib_kernel.c to fs/ncpfs/ncplib_kernel.c] Signed-off-by: Ben Hutchings --- fs/ncpfs/ncplib_kernel.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/ncpfs/ncplib_kernel.c b/fs/ncpfs/ncplib_kernel.c index 981a95617fc9..76c6a8e3e830 100644 --- a/fs/ncpfs/ncplib_kernel.c +++ b/fs/ncpfs/ncplib_kernel.c @@ -982,6 +982,10 @@ ncp_read_kernel(struct ncp_server *server, const char *file_id, goto out; } *bytes_read = ncp_reply_be16(server, 0); + if (*bytes_read > to_read) { + result = -EINVAL; + goto out; + } source = ncp_reply_data(server, 2 + (offset & 1)); memcpy(target, source, *bytes_read); -- 2.39.2