Date: Thu, 21 Jun 2012 09:20:08 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r237366 - head/sys/ufs/ffs Message-ID: <201206210920.q5L9K8t5001745@svn.freebsd.org>
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Author: kib Date: Thu Jun 21 09:20:07 2012 New Revision: 237366 URL: http://svn.freebsd.org/changeset/base/237366 Log: Fix unbounded-length malloc, controlled from usermode. The added check is performed before exact size of the buffer is calculated, but the buffer cannot have size greater then the total space allocated for extended attributes. The existing check is executing with precise size, but it is too late, since buffer needs to be allocated in advance. Also, adapt to uio_resid being of ssize_t type. Use lblktosize instead of multiplying by fs block size by hand as well. Reported and tested by: pho MFC after: 1 week Modified: head/sys/ufs/ffs/ffs_vnops.c Modified: head/sys/ufs/ffs/ffs_vnops.c ============================================================================== --- head/sys/ufs/ffs/ffs_vnops.c Thu Jun 21 09:19:41 2012 (r237365) +++ head/sys/ufs/ffs/ffs_vnops.c Thu Jun 21 09:20:07 2012 (r237366) @@ -1648,7 +1648,8 @@ vop_setextattr { struct inode *ip; struct fs *fs; uint32_t ealength, ul; - int ealen, olen, eapad1, eapad2, error, i, easize; + ssize_t ealen; + int olen, eapad1, eapad2, error, i, easize; u_char *eae, *p; ip = VTOI(ap->a_vp); @@ -1667,6 +1668,10 @@ vop_setextattr { if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY) return (EROFS); + ealen = ap->a_uio->uio_resid; + if (ealen < 0 || ealen > lblktosize(fs, NXADDR)) + return (EINVAL); + error = extattr_check_cred(ap->a_vp, ap->a_attrnamespace, ap->a_cred, ap->a_td, VWRITE); if (error) { @@ -1684,7 +1689,6 @@ vop_setextattr { if (error) return (error); - ealen = ap->a_uio->uio_resid; ealength = sizeof(uint32_t) + 3 + strlen(ap->a_name); eapad1 = 8 - (ealength % 8); if (eapad1 == 8) @@ -1712,7 +1716,7 @@ vop_setextattr { easize += (ealength - ul); } } - if (easize > NXADDR * fs->fs_bsize) { + if (easize > lblktosize(fs, NXADDR)) { free(eae, M_TEMP); ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td); if (ip->i_ea_area != NULL && ip->i_ea_error == 0)
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