Date: Fri, 21 Feb 2014 22:29:09 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r262309 - head/sys/kern Message-ID: <201402212229.s1LMT9BF093587@svn.freebsd.org>
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Author: mjg Date: Fri Feb 21 22:29:09 2014 New Revision: 262309 URL: http://svnweb.freebsd.org/changeset/base/262309 Log: Fix a race between kern_proc_{o,}filedesc_out and fdescfree leading to use-after-free. fdescfree proceeds to free file pointers once fd_refcnt reaches 0, but kern_proc_{o,}filedesc_out only checked for hold count. MFC after: 3 days Modified: head/sys/kern/kern_descrip.c Modified: head/sys/kern/kern_descrip.c ============================================================================== --- head/sys/kern/kern_descrip.c Fri Feb 21 21:54:36 2014 (r262308) +++ head/sys/kern/kern_descrip.c Fri Feb 21 22:29:09 2014 (r262309) @@ -3056,7 +3056,7 @@ sysctl_kern_proc_ofiledesc(SYSCTL_HANDLE if (fdp->fd_jdir != NULL) export_vnode_for_osysctl(fdp->fd_jdir, KF_FD_TYPE_JAIL, kif, fdp, req); - for (i = 0; i < fdp->fd_nfiles; i++) { + for (i = 0; fdp->fd_refcnt > 0 && i < fdp->fd_nfiles; i++) { if ((fp = fdp->fd_ofiles[i].fde_file) == NULL) continue; bzero(kif, sizeof(*kif)); @@ -3424,7 +3424,7 @@ kern_proc_filedesc_out(struct proc *p, export_fd_to_sb(data, KF_TYPE_VNODE, KF_FD_TYPE_JAIL, FREAD, -1, -1, NULL, efbuf); } - for (i = 0; i < fdp->fd_nfiles; i++) { + for (i = 0; fdp->fd_refcnt > 0 && i < fdp->fd_nfiles; i++) { if ((fp = fdp->fd_ofiles[i].fde_file) == NULL) continue; data = NULL;
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