git: 026cdaa3b3a9 - main - nfscl: Scan readdir reply filenames for invalid characters
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Date: Sun, 21 Jul 2024 22:57:55 UTC
The branch main has been updated by rmacklem:
URL: https://cgit.FreeBSD.org/src/commit/?id=026cdaa3b3a92574d9ac3155216e5cc0b0bd4c51
commit 026cdaa3b3a92574d9ac3155216e5cc0b0bd4c51
Author: Rick Macklem <rmacklem@FreeBSD.org>
AuthorDate: 2024-07-21 22:56:16 +0000
Commit: Rick Macklem <rmacklem@FreeBSD.org>
CommitDate: 2024-07-21 22:56:16 +0000
nfscl: Scan readdir reply filenames for invalid characters
The NFS RFCs are pretty loose with respect to what characters
can be in a filename returned by a Readdir. However, FreeBSD,
as a POSIX system will not handle imbedded '/' or nul characters
in file names. Also, for NFSv4, the file names "." and ".."
are handcrafted on the client and should not be returned by a
NFSv4 server.
This patch scans for the above in filenames returned by Readdir and
ignores any entry returned by Readdir which has them in it.
Because an imbedded nul would be a string terminator, it was
not possible to code this check efficiently using string(3)
functions.
Reported by: Apple Security Engineering and Architecture (SEAR)
MFC after: 1 week
---
sys/fs/nfsclient/nfs_clrpcops.c | 137 ++++++++++++++++++++++++++++++++--------
1 file changed, 110 insertions(+), 27 deletions(-)
diff --git a/sys/fs/nfsclient/nfs_clrpcops.c b/sys/fs/nfsclient/nfs_clrpcops.c
index 13bdc74655dd..8947b608b743 100644
--- a/sys/fs/nfsclient/nfs_clrpcops.c
+++ b/sys/fs/nfsclient/nfs_clrpcops.c
@@ -142,6 +142,7 @@ static int nfsrpc_createv4(vnode_t , char *, int, struct vattr *,
nfsquad_t, int, struct nfsclowner *, struct nfscldeleg **, struct ucred *,
NFSPROC_T *, struct nfsvattr *, struct nfsvattr *, struct nfsfh **, int *,
int *, int *);
+static bool nfscl_invalidfname(bool, char *, int);
static int nfsrpc_locku(struct nfsrv_descript *, struct nfsmount *,
struct nfscllockowner *, u_int64_t, u_int64_t,
u_int32_t, struct ucred *, NFSPROC_T *, int);
@@ -3321,6 +3322,31 @@ nfsrpc_rmdir(vnode_t dvp, char *name, int namelen, struct ucred *cred,
return (error);
}
+/*
+ * Check to make sure the file name in a Readdir reply is valid.
+ */
+static bool
+nfscl_invalidfname(bool is_v4, char *name, int len)
+{
+ int i;
+ char *cp;
+
+ if (is_v4 && ((len == 1 && name[0] == '.') ||
+ (len == 2 && name[0] == '.' && name[1] == '.'))) {
+ printf("Readdir NFSv4 reply has dot or dotdot in it\n");
+ return (true);
+ }
+ cp = name;
+ for (i = 0; i < len; i++, cp++) {
+ if (*cp == '/' || *cp == '\0') {
+ printf("Readdir reply file name had imbedded / or nul"
+ " byte\n");
+ return (true);
+ }
+ }
+ return (false);
+}
+
/*
* Readdir rpc.
* Always returns with either uio_resid unchanged, if you are at the
@@ -3373,6 +3399,8 @@ nfsrpc_readdir(vnode_t vp, struct uio *uiop, nfsuint64 *cookiep,
KASSERT(uiop->uio_iovcnt == 1 &&
(uiop->uio_resid & (DIRBLKSIZ - 1)) == 0,
("nfs readdirrpc bad uio"));
+ KASSERT(uiop->uio_segflg == UIO_SYSSPACE,
+ ("nfsrpc_readdir: uio userspace"));
ncookie.lval[0] = ncookie.lval[1] = 0;
/*
* There is no point in reading a lot more than uio_resid, however
@@ -3630,6 +3658,17 @@ nfsrpc_readdir(vnode_t vp, struct uio *uiop, nfsuint64 *cookiep,
uiop->uio_resid)
bigenough = 0;
if (bigenough) {
+ struct iovec saviov;
+ off_t savoff;
+ ssize_t savresid;
+ int savblksiz;
+
+ saviov.iov_base = uiop->uio_iov->iov_base;
+ saviov.iov_len = uiop->uio_iov->iov_len;
+ savoff = uiop->uio_offset;
+ savresid = uiop->uio_resid;
+ savblksiz = blksiz;
+
dp = (struct dirent *)uiop->uio_iov->iov_base;
dp->d_pad0 = dp->d_pad1 = 0;
dp->d_off = 0;
@@ -3645,20 +3684,35 @@ nfsrpc_readdir(vnode_t vp, struct uio *uiop, nfsuint64 *cookiep,
uiop->uio_iov->iov_base =
(char *)uiop->uio_iov->iov_base + DIRHDSIZ;
uiop->uio_iov->iov_len -= DIRHDSIZ;
+ cp = uiop->uio_iov->iov_base;
error = nfsm_mbufuio(nd, uiop, len);
if (error)
goto nfsmout;
- cp = uiop->uio_iov->iov_base;
- tlen -= len;
- NFSBZERO(cp, tlen);
- cp += tlen; /* points to cookie storage */
- tl2 = (u_int32_t *)cp;
- uiop->uio_iov->iov_base =
- (char *)uiop->uio_iov->iov_base + tlen +
- NFSX_HYPER;
- uiop->uio_iov->iov_len -= tlen + NFSX_HYPER;
- uiop->uio_resid -= tlen + NFSX_HYPER;
- uiop->uio_offset += (tlen + NFSX_HYPER);
+ /* Check for an invalid file name. */
+ if (nfscl_invalidfname(
+ (nd->nd_flag & ND_NFSV4) != 0, cp, len)) {
+ /* Skip over this entry. */
+ uiop->uio_iov->iov_base =
+ saviov.iov_base;
+ uiop->uio_iov->iov_len =
+ saviov.iov_len;
+ uiop->uio_offset = savoff;
+ uiop->uio_resid = savresid;
+ blksiz = savblksiz;
+ } else {
+ cp = uiop->uio_iov->iov_base;
+ tlen -= len;
+ NFSBZERO(cp, tlen);
+ cp += tlen; /* points to cookie store */
+ tl2 = (u_int32_t *)cp;
+ uiop->uio_iov->iov_base =
+ (char *)uiop->uio_iov->iov_base +
+ tlen + NFSX_HYPER;
+ uiop->uio_iov->iov_len -= tlen +
+ NFSX_HYPER;
+ uiop->uio_resid -= tlen + NFSX_HYPER;
+ uiop->uio_offset += (tlen + NFSX_HYPER);
+ }
} else {
error = nfsm_advance(nd, NFSM_RNDUP(len), -1);
if (error)
@@ -3824,6 +3878,8 @@ nfsrpc_readdirplus(vnode_t vp, struct uio *uiop, nfsuint64 *cookiep,
KASSERT(uiop->uio_iovcnt == 1 &&
(uiop->uio_resid & (DIRBLKSIZ - 1)) == 0,
("nfs readdirplusrpc bad uio"));
+ KASSERT(uiop->uio_segflg == UIO_SYSSPACE,
+ ("nfsrpc_readdirplus: uio userspace"));
ncookie.lval[0] = ncookie.lval[1] = 0;
timespecclear(&dctime);
*attrflagp = 0;
@@ -4059,6 +4115,17 @@ nfsrpc_readdirplus(vnode_t vp, struct uio *uiop, nfsuint64 *cookiep,
uiop->uio_resid)
bigenough = 0;
if (bigenough) {
+ struct iovec saviov;
+ off_t savoff;
+ ssize_t savresid;
+ int savblksiz;
+
+ saviov.iov_base = uiop->uio_iov->iov_base;
+ saviov.iov_len = uiop->uio_iov->iov_len;
+ savoff = uiop->uio_offset;
+ savresid = uiop->uio_resid;
+ savblksiz = blksiz;
+
dp = (struct dirent *)uiop->uio_iov->iov_base;
dp->d_pad0 = dp->d_pad1 = 0;
dp->d_off = 0;
@@ -4077,25 +4144,41 @@ nfsrpc_readdirplus(vnode_t vp, struct uio *uiop, nfsuint64 *cookiep,
cnp->cn_nameptr = uiop->uio_iov->iov_base;
cnp->cn_namelen = len;
NFSCNHASHZERO(cnp);
+ cp = uiop->uio_iov->iov_base;
error = nfsm_mbufuio(nd, uiop, len);
if (error)
goto nfsmout;
- cp = uiop->uio_iov->iov_base;
- tlen -= len;
- NFSBZERO(cp, tlen);
- cp += tlen; /* points to cookie storage */
- tl2 = (u_int32_t *)cp;
- if (len == 2 && cnp->cn_nameptr[0] == '.' &&
- cnp->cn_nameptr[1] == '.')
- isdotdot = 1;
- else
- isdotdot = 0;
- uiop->uio_iov->iov_base =
- (char *)uiop->uio_iov->iov_base + tlen +
- NFSX_HYPER;
- uiop->uio_iov->iov_len -= tlen + NFSX_HYPER;
- uiop->uio_resid -= tlen + NFSX_HYPER;
- uiop->uio_offset += (tlen + NFSX_HYPER);
+ /* Check for an invalid file name. */
+ if (nfscl_invalidfname(
+ (nd->nd_flag & ND_NFSV4) != 0, cp, len)) {
+ /* Skip over this entry. */
+ uiop->uio_iov->iov_base =
+ saviov.iov_base;
+ uiop->uio_iov->iov_len =
+ saviov.iov_len;
+ uiop->uio_offset = savoff;
+ uiop->uio_resid = savresid;
+ blksiz = savblksiz;
+ } else {
+ cp = uiop->uio_iov->iov_base;
+ tlen -= len;
+ NFSBZERO(cp, tlen);
+ cp += tlen; /* points to cookie store */
+ tl2 = (u_int32_t *)cp;
+ if (len == 2 &&
+ cnp->cn_nameptr[0] == '.' &&
+ cnp->cn_nameptr[1] == '.')
+ isdotdot = 1;
+ else
+ isdotdot = 0;
+ uiop->uio_iov->iov_base =
+ (char *)uiop->uio_iov->iov_base +
+ tlen + NFSX_HYPER;
+ uiop->uio_iov->iov_len -= tlen +
+ NFSX_HYPER;
+ uiop->uio_resid -= tlen + NFSX_HYPER;
+ uiop->uio_offset += (tlen + NFSX_HYPER);
+ }
} else {
error = nfsm_advance(nd, NFSM_RNDUP(len), -1);
if (error)