From 66ace87da47b8036dd8ac2ab2e66ab0042c0d252 Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Sun, 3 Jan 2021 11:32:30 -0500 Subject: [PATCH] Ensure that dirent's d_off field is initialized We have the d_off field in struct dirent for providing the seek offset of the next directory entry. Several filesystems were not initializing the field, which ends up being copied out to userland. Reported by: Syed Faraz Abrar Reviewed by: kib (cherry picked from commit 90f580b954090e669da234f6c8e8d0379ff9d8bc) (cherry picked from commit acaac0eefa1f2675dfc49faa077e3fb10949d540) Approved by: so Security: CVE-2020-25578 --- sys/fs/autofs/autofs_vnops.c | 1 + sys/fs/smbfs/smbfs_io.c | 2 ++ sys/fs/tmpfs/tmpfs_subr.c | 50 +++++++++++++++++++++++------------- sys/kern/uipc_mqueue.c | 1 + 4 files changed, 36 insertions(+), 18 deletions(-) diff --git a/sys/fs/autofs/autofs_vnops.c b/sys/fs/autofs/autofs_vnops.c index 09d77b9fccf..ac5886f9605 100644 --- a/sys/fs/autofs/autofs_vnops.c +++ b/sys/fs/autofs/autofs_vnops.c @@ -369,6 +369,7 @@ autofs_readdir_one(struct uio *uio, const char *name, int fileno, return (EINVAL); dirent.d_fileno = fileno; + dirent.d_off = uio->uio_offset + reclen; dirent.d_reclen = reclen; dirent.d_type = DT_DIR; dirent.d_namlen = namlen; diff --git a/sys/fs/smbfs/smbfs_io.c b/sys/fs/smbfs/smbfs_io.c index 790538d7ce8..78a11309edc 100644 --- a/sys/fs/smbfs/smbfs_io.c +++ b/sys/fs/smbfs/smbfs_io.c @@ -103,6 +103,7 @@ smbfs_readvdir(struct vnode *vp, struct uio *uio, struct ucred *cred) (np->n_parent ? np->n_parentino : 2); if (de.d_fileno == 0) de.d_fileno = 0x7ffffffd + offset; + de.d_off = offset + 1; de.d_namlen = offset + 1; de.d_name[0] = '.'; de.d_name[1] = '.'; @@ -153,6 +154,7 @@ smbfs_readvdir(struct vnode *vp, struct uio *uio, struct ucred *cred) bzero((caddr_t)&de, DE_SIZE); de.d_reclen = DE_SIZE; de.d_fileno = ctx->f_attr.fa_ino; + de.d_off = offset + 1; de.d_type = (ctx->f_attr.fa_attr & SMB_FA_DIR) ? DT_DIR : DT_REG; de.d_namlen = ctx->f_nmlen; bcopy(ctx->f_name, de.d_name, de.d_namlen); diff --git a/sys/fs/tmpfs/tmpfs_subr.c b/sys/fs/tmpfs/tmpfs_subr.c index 4727564de96..cf041a2691e 100644 --- a/sys/fs/tmpfs/tmpfs_subr.c +++ b/sys/fs/tmpfs/tmpfs_subr.c @@ -1122,6 +1122,7 @@ tmpfs_dir_getdotdent(struct tmpfs_mount *tm, struct tmpfs_node *node, MPASS(uio->uio_offset == TMPFS_DIRCOOKIE_DOT); dent.d_fileno = node->tn_id; + dent.d_off = TMPFS_DIRCOOKIE_DOTDOT; dent.d_type = DT_DIR; dent.d_namlen = 1; dent.d_name[0] = '.'; @@ -1147,7 +1148,7 @@ tmpfs_dir_getdotdent(struct tmpfs_mount *tm, struct tmpfs_node *node, */ static int tmpfs_dir_getdotdotdent(struct tmpfs_mount *tm, struct tmpfs_node *node, - struct uio *uio) + struct uio *uio, off_t next) { struct tmpfs_node *parent; struct dirent dent; @@ -1168,6 +1169,7 @@ tmpfs_dir_getdotdotdent(struct tmpfs_mount *tm, struct tmpfs_node *node, dent.d_fileno = parent->tn_id; TMPFS_NODE_UNLOCK(parent); + dent.d_off = next; dent.d_type = DT_DIR; dent.d_namlen = 2; dent.d_name[0] = '.'; @@ -1197,7 +1199,7 @@ tmpfs_dir_getdents(struct tmpfs_mount *tm, struct tmpfs_node *node, struct uio *uio, int maxcookies, u_long *cookies, int *ncookies) { struct tmpfs_dir_cursor dc; - struct tmpfs_dirent *de; + struct tmpfs_dirent *de, *nde; off_t off; int error; @@ -1218,18 +1220,19 @@ tmpfs_dir_getdents(struct tmpfs_mount *tm, struct tmpfs_node *node, error = tmpfs_dir_getdotdent(tm, node, uio); if (error != 0) return (error); - uio->uio_offset = TMPFS_DIRCOOKIE_DOTDOT; + uio->uio_offset = off = TMPFS_DIRCOOKIE_DOTDOT; if (cookies != NULL) - cookies[(*ncookies)++] = off = uio->uio_offset; + cookies[(*ncookies)++] = off; /* FALLTHROUGH */ case TMPFS_DIRCOOKIE_DOTDOT: - error = tmpfs_dir_getdotdotdent(tm, node, uio); + de = tmpfs_dir_first(node, &dc); + off = tmpfs_dirent_cookie(de); + error = tmpfs_dir_getdotdotdent(tm, node, uio, off); if (error != 0) return (error); - de = tmpfs_dir_first(node, &dc); - uio->uio_offset = tmpfs_dirent_cookie(de); + uio->uio_offset = off; if (cookies != NULL) - cookies[(*ncookies)++] = off = uio->uio_offset; + cookies[(*ncookies)++] = off; /* EOF. */ if (de == NULL) return (0); @@ -1244,13 +1247,17 @@ tmpfs_dir_getdents(struct tmpfs_mount *tm, struct tmpfs_node *node, off = tmpfs_dirent_cookie(de); } - /* Read as much entries as possible; i.e., until we reach the end of - * the directory or we exhaust uio space. */ + /* + * Read as much entries as possible; i.e., until we reach the end of the + * directory or we exhaust uio space. + */ do { struct dirent d; - /* Create a dirent structure representing the current - * tmpfs_node and fill it. */ + /* + * Create a dirent structure representing the current tmpfs_node + * and fill it. + */ if (de->td_node == NULL) { d.d_fileno = 1; d.d_type = DT_WHT; @@ -1294,20 +1301,27 @@ tmpfs_dir_getdents(struct tmpfs_mount *tm, struct tmpfs_node *node, MPASS(de->td_namelen < sizeof(d.d_name)); (void)memcpy(d.d_name, de->ud.td_name, de->td_namelen); d.d_reclen = GENERIC_DIRSIZ(&d); - dirent_terminate(&d); - /* Stop reading if the directory entry we are treating is - * bigger than the amount of data that can be returned. */ + /* + * Stop reading if the directory entry we are treating is bigger + * than the amount of data that can be returned. + */ if (d.d_reclen > uio->uio_resid) { error = EJUSTRETURN; break; } - /* Copy the new dirent structure into the output buffer and - * advance pointers. */ + nde = tmpfs_dir_next(node, &dc); + d.d_off = tmpfs_dirent_cookie(nde); + dirent_terminate(&d); + + /* + * Copy the new dirent structure into the output buffer and + * advance pointers. + */ error = uiomove(&d, d.d_reclen, uio); if (error == 0) { - de = tmpfs_dir_next(node, &dc); + de = nde; if (cookies != NULL) { off = tmpfs_dirent_cookie(de); MPASS(*ncookies < maxcookies); diff --git a/sys/kern/uipc_mqueue.c b/sys/kern/uipc_mqueue.c index 67c828cae22..84f51fafb63 100644 --- a/sys/kern/uipc_mqueue.c +++ b/sys/kern/uipc_mqueue.c @@ -1426,6 +1426,7 @@ mqfs_readdir(struct vop_readdir_args *ap) if (!pn->mn_fileno) mqfs_fileno_alloc(mi, pn); entry.d_fileno = pn->mn_fileno; + entry.d_off = offset + entry.d_reclen; for (i = 0; i < MQFS_NAMELEN - 1 && pn->mn_name[i] != '\0'; ++i) entry.d_name[i] = pn->mn_name[i]; entry.d_namlen = i; -- 2.45.0