CVE-2011-4131: nfs4_getfacl decoding kernel oops (rhbz 753236) CVE-2011-4132: jbd/jbd2: invalid value of first log block leads to oops (rhbz 753346)
119 lines
4.2 KiB
Diff
119 lines
4.2 KiB
Diff
From: Andy Adamson <andros@xxxxxxxxxx>
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The NFSv4 bitmap size is unbounded: a server can return an arbitrary
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sized bitmap in an FATTR4_WORD0_ACL request. Replace using the
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nfs4_fattr_bitmap_maxsz as a guess to the maximum bitmask returned by a server
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with the inclusion of the bitmap (xdr length plus bitmasks) and the acl data
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xdr length to the (cached) acl page data.
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This is a general solution to commit e5012d1f "NFSv4.1: update
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nfs4_fattr_bitmap_maxsz" and fixes hitting a BUG_ON in xdr_shrink_bufhead
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when getting ACLs.
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Cc:stable@xxxxxxxxxx
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Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
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---
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fs/nfs/nfs4proc.c | 20 ++++++++++++++++++--
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fs/nfs/nfs4xdr.c | 15 ++++++++++++---
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2 files changed, 30 insertions(+), 5 deletions(-)
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diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
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index deb88d9..97014dd 100644
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--- a/fs/nfs/nfs4proc.c
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+++ b/fs/nfs/nfs4proc.c
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@@ -3671,6 +3671,22 @@ static void nfs4_zap_acl_attr(struct inode *inode)
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nfs4_set_cached_acl(inode, NULL);
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}
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+/*
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+ * The bitmap xdr length, bitmasks, and the attr xdr length are stored in
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+ * the acl cache to handle variable length bitmasks. Just copy the acl data.
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+ */
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+static void nfs4_copy_acl(char *buf, char *acl_data, size_t acl_len)
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+{
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+ __be32 *q, *p = (__be32 *)acl_data;
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+ int32_t len;
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+
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+ len = be32_to_cpup(p); /* number of bitmasks */
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+ len += 2; /* add words for bitmap and attr xdr len */
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+ q = p + len;
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+ len = len << 2; /* convert to bytes for acl_len math */
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+ memcpy(buf, (char *)q, acl_len - len);
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+}
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+
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static inline ssize_t nfs4_read_cached_acl(struct inode *inode, char *buf, size_t buflen)
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{
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struct nfs_inode *nfsi = NFS_I(inode);
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@@ -3688,7 +3704,7 @@ static inline ssize_t nfs4_read_cached_acl(struct inode *inode, char *buf, size_
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ret = -ERANGE; /* see getxattr(2) man page */
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if (acl->len > buflen)
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goto out;
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- memcpy(buf, acl->data, acl->len);
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+ nfs4_copy_acl(buf, acl->data, acl->len);
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out_len:
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ret = acl->len;
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out:
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@@ -3763,7 +3779,7 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu
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if (res.acl_len > buflen)
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goto out_free;
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if (localpage)
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- memcpy(buf, resp_buf, res.acl_len);
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+ nfs4_copy_acl(buf, resp_buf, res.acl_len);
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}
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ret = res.acl_len;
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out_free:
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diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
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index f9fd96d..9c07380 100644
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--- a/fs/nfs/nfs4xdr.c
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+++ b/fs/nfs/nfs4xdr.c
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@@ -2513,7 +2513,7 @@ static void nfs4_xdr_enc_getacl(struct rpc_rqst *req, struct xdr_stream *xdr,
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encode_compound_hdr(xdr, req, &hdr);
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encode_sequence(xdr, &args->seq_args, &hdr);
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encode_putfh(xdr, args->fh, &hdr);
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- replen = hdr.replen + op_decode_hdr_maxsz + nfs4_fattr_bitmap_maxsz + 1;
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+ replen = hdr.replen + op_decode_hdr_maxsz + 1;
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encode_getattr_two(xdr, FATTR4_WORD0_ACL, 0, &hdr);
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xdr_inline_pages(&req->rq_rcv_buf, replen << 2,
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@@ -4955,7 +4955,7 @@ decode_restorefh(struct xdr_stream *xdr)
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static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
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size_t *acl_len)
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{
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- __be32 *savep;
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+ __be32 *savep, *bm_p;
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uint32_t attrlen,
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bitmap[3] = {0};
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struct kvec *iov = req->rq_rcv_buf.head;
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@@ -4964,6 +4964,7 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
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*acl_len = 0;
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if ((status = decode_op_hdr(xdr, OP_GETATTR)) != 0)
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goto out;
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+ bm_p = xdr->p;
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if ((status = decode_attr_bitmap(xdr, bitmap)) != 0)
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goto out;
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if ((status = decode_attr_length(xdr, &attrlen, &savep)) != 0)
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@@ -4972,12 +4973,20 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
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if (unlikely(bitmap[0] & (FATTR4_WORD0_ACL - 1U)))
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return -EIO;
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if (likely(bitmap[0] & FATTR4_WORD0_ACL)) {
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- size_t hdrlen;
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+ size_t hdrlen, len;
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u32 recvd;
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+ /*The bitmap (xdr len + bitmasks) and the attr xdr len words
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+ * are stored with the acl data to handle the problem of
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+ * variable length bitmasks.*/
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+ xdr->p = bm_p;
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+ len = be32_to_cpup(bm_p);
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+ len += 2; /* add bitmap and attr xdr len words */
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+
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/* We ignore &savep and don't do consistency checks on
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* the attr length. Let userspace figure it out.... */
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hdrlen = (u8 *)xdr->p - (u8 *)iov->iov_base;
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+ attrlen += len << 2; /* attrlen is in bytes */
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recvd = req->rq_rcv_buf.len - hdrlen;
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if (attrlen > recvd) {
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dprintk("NFS: server cheating in getattr"
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--
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1.7.6.4
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