| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 101/173] cifs: prevent integer overflow in nxt_dir_entry() | Date | Mon, 24 Sep 2018 13:52:15 +0200 |
| |
4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dan Carpenter <dan.carpenter@oracle.com>
commit 8ad8aa353524d89fa2e09522f3078166ff78ec42 upstream.
The "old_entry + le32_to_cpu(pDirInfo->NextEntryOffset)" can wrap around so I have added a check for integer overflow.
Reported-by: Dr Silvio Cesare of InfoSect <silvio.cesare@gmail.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Steve French <stfrench@microsoft.com> CC: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/cifs/readdir.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
--- a/fs/cifs/readdir.c +++ b/fs/cifs/readdir.c @@ -376,8 +376,15 @@ static char *nxt_dir_entry(char *old_ent new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) + pfData->FileNameLength; - } else - new_entry = old_entry + le32_to_cpu(pDirInfo->NextEntryOffset); + } else { + u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset); + + if (old_entry + next_offset < old_entry) { + cifs_dbg(VFS, "invalid offset %u\n", next_offset); + return NULL; + } + new_entry = old_entry + next_offset; + } cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry); /* validate that new_entry is not past end of SMB */ if (new_entry >= end_of_smb) {
|