lkml.org 
[lkml]   [2018]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.18 134/235] cifs: prevent integer overflow in nxt_dir_entry()
    Date
    4.18-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) {

    \
     
     \ /
      Last update: 2018-09-24 14:39    [W:4.213 / U:0.012 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site