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    SubjectRe: [PATCH 2.6] Check return value of copy_to_user in fs/cifs/file.c [Re: Linux 2.6.11-rc4]
    Il Sun, Feb 13, 2005 at 06:28:38PM +0100, Marcel Sebek ha scritto: 
    > > @@ -1164,13 +1164,22 @@
    > > current_read_size, *poffset,
    > > &bytes_read, &smb_read_data);
    > >
    > > + if (rc == -EAGAIN)
    > > + continue;
    > > + else
    > > + break;
    > > +
    > > pSMBr = (struct smb_com_read_rsp *)smb_read_data;
    > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    > Perhaps this line and the following lines are never executed with your
    > patch, am I right?

    Yes, you are. Let's try again:

    The following patch against 2.6.11-rc4 fixes this compile time
    warning:

    CC [M] fs/cifs/file.o
    fs/cifs/file.c: In function `cifs_user_read':
    fs/cifs/file.c:1168: warning: ignoring return value of
    `copy_to_user', declared with attribute warn_unused_result

    I also added an explicit check for errors other than -EAGAIN, since
    CIFSSMBRead may return -ENOMEM if it's unable to allocate
    smb_com_read_rsp; in that case we don't want to call copy_to_user with a
    NULL pointer.

    Signed-off-by: Luca Tettamanti <kronoz@kronoz.cjb.net>

    --- a/fs/cifs/file.c 2005-02-03 17:58:07.000000000 +0100
    +++ b/fs/cifs/file.c 2005-02-13 21:18:01.000000000 +0100
    @@ -1151,7 +1151,7 @@
    current_read_size = min_t(const int,read_size - total_read,cifs_sb->rsize);
    rc = -EAGAIN;
    smb_read_data = NULL;
    - while(rc == -EAGAIN) {
    + while(1) {
    if ((open_file->invalidHandle) && (!open_file->closePend)) {
    rc = cifs_reopen_file(file->f_dentry->d_inode,
    file,TRUE);
    @@ -1164,13 +1164,22 @@
    current_read_size, *poffset,
    &bytes_read, &smb_read_data);

    + if (rc == -EAGAIN)
    + continue;
    + if (rc)
    + break;
    +
    pSMBr = (struct smb_com_read_rsp *)smb_read_data;
    - copy_to_user(current_offset,smb_read_data + 4/* RFC1001 hdr*/
    + rc = copy_to_user(current_offset,smb_read_data + 4/* RFC1001 hdr*/
    + le16_to_cpu(pSMBr->DataOffset), bytes_read);
    if(smb_read_data) {
    cifs_buf_release(smb_read_data);
    smb_read_data = NULL;
    }
    + if (rc) {
    + FreeXid(xid);
    + return -EFAULT;
    + }
    }
    if (rc || (bytes_read == 0)) {
    if (total_read) {

    Luca
    --
    Home: http://kronoz.cjb.net
    "La teoria e` quando sappiamo come funzionano le cose ma non funzionano.
    La pratica e` quando le cose funzionano ma non sappiamo perche`.
    Abbiamo unito la teoria e la pratica: le cose non funzionano piu` e non
    sappiamo il perche`." -- A. Einstein
    -
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