kern/117010: [linux] linux_getdents() get something like buffer
overflow or else
Roman Divacky
rdivacky at freebsd.org
Mon Sep 8 07:04:56 UTC 2008
On Mon, Sep 08, 2008 at 01:12:28AM +0400, Chagin Dmitry wrote:
> On Sun, Sep 07, 2008 at 08:30:04PM +0000, MITA Yoshio wrote:
> > The following reply was made to PR kern/117010; it has been noted by GNATS.
> >
> > From: MITA Yoshio <mita at ee.t.u-tokyo.ac.jp>
> > To: bug-followup at FreeBSD.org,samflanker at gmail.com,
> > Chagin Dmitry <chagin.dmitry at gmail.com>,
> > beech at FreeBSD.org
> > Cc:
> > Subject: Re: kern/117010: [linux] linux_getdents() get something like buffer overflow or else
> > Date: Sun, 07 Sep 2008 21:42:15 +0200
> >
> > Hello,
> >
> > I've tested a patch from Mr. Dmitry concerning Mr. Ermakov's PR:
> >
> > http://www.freebsd.org/cgi/query-pr.cgi?pr=117010
> >
> > Patch:
> > >From: Chagin Dmitry <chagin.dmitry at gmail.com>
> > >Date: Fri, 25 Jul 2008 10:22:46 +0400 (MSD)
> >
> > This worked!!! to make skype2 work.
> > Otherwise skype2 dumped core as Mr. reported.
> >
> > Regards,
> > -----
> > Tested Environment:
> > FreeBSD 7.0-RELEASE
> > linux_base-fc6-6_5
> > linux-glib2-2.6.6
> > skype-2.0.0.68,1
> >
> > /etc/sysctl.conf:
> > compat.linux.osrelease=2.6.16
> >
> > /etc/make.conf:
> > OVERRIDE_LINUX_BASE_PORT=fc6
>
> Please, try a patch bellow:
>
> diff --git a/src/sys/compat/linux/linux_file.c b/src/sys/compat/linux/linux_file.c
> index 303bc3f..413e597 100644
> --- a/src/sys/compat/linux/linux_file.c
> +++ b/src/sys/compat/linux/linux_file.c
> @@ -303,9 +303,20 @@ struct l_dirent64 {
> char d_name[LINUX_NAME_MAX + 1];
> };
>
> -#define LINUX_RECLEN(de,namlen) \
> - ALIGN((((char *)&(de)->d_name - (char *)de) + (namlen) + 1))
> +/*
> + * Linux uses the last byte in the dirent buffer to store d_type,
> + * at least glibc-2.7 requires it. For what l_dirent padded on 2 bytes.
> + */
> +#define LINUX_RECLEN(namlen) \
> + roundup((offsetof(struct l_dirent, d_name) + (namlen) + 2), \
> + sizeof(l_ulong))
> +
> +#define LINUX_RECLEN64(namlen) \
> + roundup((offsetof(struct l_dirent64, d_name) + (namlen) + 1), \
> + sizeof(uint64_t))
>
> +#define LINUX_MAXRECLEN max(LINUX_RECLEN(LINUX_NAME_MAX), \
> + LINUX_RECLEN64(LINUX_NAME_MAX))
> #define LINUX_DIRBLKSIZ 512
>
> static int
> @@ -318,12 +329,13 @@ getdents_common(struct thread *td, struct linux_getdents64_args *args,
> int len, reclen; /* BSD-format */
> caddr_t outp; /* Linux-format */
> int resid, linuxreclen=0; /* Linux-format */
> + caddr_t lbuf; /* Linux-format */
> struct file *fp;
> struct uio auio;
> struct iovec aiov;
> off_t off;
> - struct l_dirent linux_dirent;
> - struct l_dirent64 linux_dirent64;
> + struct l_dirent *linux_dirent;
> + struct l_dirent64 *linux_dirent64;
> int buflen, error, eofflag, nbytes, justone;
> u_long *cookies = NULL, *cookiep;
> int ncookies, vfslocked;
> @@ -359,6 +371,7 @@ getdents_common(struct thread *td, struct linux_getdents64_args *args,
> buflen = max(LINUX_DIRBLKSIZ, nbytes);
> buflen = min(buflen, MAXBSIZE);
> buf = malloc(buflen, M_TEMP, M_WAITOK);
> + lbuf = malloc(LINUX_MAXRECLEN, M_TEMP, M_WAITOK | M_ZERO);
> vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
>
> again:
> @@ -436,8 +449,8 @@ again:
> }
>
> linuxreclen = (is64bit)
> - ? LINUX_RECLEN(&linux_dirent64, bdp->d_namlen)
> - : LINUX_RECLEN(&linux_dirent, bdp->d_namlen);
> + ? LINUX_RECLEN64(bdp->d_namlen)
> + : LINUX_RECLEN(bdp->d_namlen);
>
> if (reclen > len || resid < linuxreclen) {
> outp++;
> @@ -446,34 +459,41 @@ again:
>
> if (justone) {
> /* readdir(2) case. */
> - linux_dirent.d_ino = bdp->d_fileno;
> - linux_dirent.d_off = (l_off_t)linuxreclen;
> - linux_dirent.d_reclen = (l_ushort)bdp->d_namlen;
> - strcpy(linux_dirent.d_name, bdp->d_name);
> - error = copyout(&linux_dirent, outp, linuxreclen);
> - } else {
> - if (is64bit) {
> - linux_dirent64.d_ino = bdp->d_fileno;
> - linux_dirent64.d_off = (cookiep)
> - ? (l_off_t)*cookiep
> - : (l_off_t)(off + reclen);
> - linux_dirent64.d_reclen =
> - (l_ushort)linuxreclen;
> - linux_dirent64.d_type = bdp->d_type;
> - strcpy(linux_dirent64.d_name, bdp->d_name);
> - error = copyout(&linux_dirent64, outp,
> - linuxreclen);
> - } else {
> - linux_dirent.d_ino = bdp->d_fileno;
> - linux_dirent.d_off = (cookiep)
> - ? (l_off_t)*cookiep
> - : (l_off_t)(off + reclen);
> - linux_dirent.d_reclen = (l_ushort)linuxreclen;
> - strcpy(linux_dirent.d_name, bdp->d_name);
> - error = copyout(&linux_dirent, outp,
> - linuxreclen);
> - }
> + linux_dirent = (struct l_dirent*)lbuf;
> + linux_dirent->d_ino = bdp->d_fileno;
> + linux_dirent->d_off = (l_off_t)linuxreclen;
> + linux_dirent->d_reclen = (l_ushort)bdp->d_namlen;
> + strlcpy(linux_dirent->d_name, bdp->d_name,
> + linuxreclen - offsetof(struct l_dirent, d_name));
> + error = copyout(linux_dirent, outp, linuxreclen);
> }
> + if (is64bit) {
> + linux_dirent64 = (struct l_dirent64*)lbuf;
> + linux_dirent64->d_ino = bdp->d_fileno;
> + linux_dirent64->d_off = (cookiep)
> + ? (l_off_t)*cookiep
> + : (l_off_t)(off + reclen);
> + linux_dirent64->d_reclen = (l_ushort)linuxreclen;
> + linux_dirent64->d_type = bdp->d_type;
> + strlcpy(linux_dirent64->d_name, bdp->d_name,
> + linuxreclen - offsetof(struct l_dirent64, d_name));
> + error = copyout(linux_dirent64, outp, linuxreclen);
> + } else if (!justone) {
> + linux_dirent = (struct l_dirent*)lbuf;
> + linux_dirent->d_ino = bdp->d_fileno;
> + linux_dirent->d_off = (cookiep)
> + ? (l_off_t)*cookiep
> + : (l_off_t)(off + reclen);
> + linux_dirent->d_reclen = (l_ushort)linuxreclen;
> + /*
> + * Copy d_type to last byte of l_dirent buffer
> + */
> + lbuf[linuxreclen-1] = bdp->d_type;
> + strlcpy(linux_dirent->d_name, bdp->d_name,
> + linuxreclen - offsetof(struct l_dirent, d_name)-1);
> + error = copyout(linux_dirent, outp, linuxreclen);
> + }
> +
> if (error)
> goto out;
>
> @@ -509,6 +529,7 @@ out:
> VFS_UNLOCK_GIANT(vfslocked);
> fdrop(fp, td);
> free(buf, M_TEMP);
> + free(lbuf, M_TEMP);
> return (error);
> }
>
>
> Roman, I think that this patch can be commited (if testing passes :))
> thnx!
yes.... this is the version of the patch I posted to you + the comment changed, right?
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