From: Sascha Hauer <[email protected]> The NFS code has hardly any length checks and it blindly trusts length values in incoming packets. Fix this by introducing a nfs_packet_read() which is consistently used to read from an incoming packet.
After a packet has been consumed it must be freed with nfs_free_packet(). This wasn't done in several error cases and is fixed here as well. Link: https://lore.barebox.org/[email protected] Signed-off-by: Sascha Hauer <[email protected]> (cherry picked from commit 5be38817bc771cc68b667f01047c4e3cac081787) Signed-off-by: Ahmad Fatoum <[email protected]> --- fs/nfs.c | 306 ++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 233 insertions(+), 73 deletions(-) diff --git a/fs/nfs.c b/fs/nfs.c index bac5cd5a183f..4367da17ace8 100644 --- a/fs/nfs.c +++ b/fs/nfs.c @@ -130,7 +130,8 @@ struct nfs_fh { struct packet { struct list_head list; - int len; + unsigned int len; + unsigned int pos; char data[]; }; @@ -393,6 +394,51 @@ static int decode_filename(struct xdr_stream *xdr, char *name, u32 *length) return -EIO; } +/* + * Read @len bytes from a NFS packets. Returns a pointer to the data + * or NULL if the packet doesn't contain enough data + */ +static void *nfs_packet_read(struct packet *nfs_packet, unsigned int len) +{ + void *ret; + + if (nfs_packet->pos + len > nfs_packet->len) { + nfs_packet->pos = nfs_packet->len; + return NULL; + } + + ret = &nfs_packet->data[0]; + ret += nfs_packet->pos; + + nfs_packet->pos += len; + + return ret; +} + +/* + * Return the remaining packet data as an allocated buffer + */ +static void *nfs_packet_memdup_rest(struct packet *nfs_packet, unsigned int *len) +{ + void *p; + + *len = nfs_packet->len - nfs_packet->pos; + + p = nfs_packet_read(nfs_packet, *len); + if (!p) + return NULL; + + return xmemdup(p, *len); +} + +/* + * Align the read pointer of a NFS packet + */ +static void nfs_read_align(struct packet *nfs_packet, unsigned int align) +{ + nfs_packet->pos = ALIGN(nfs_packet->pos, align); +} + /* * rpc_add_credentials - Add RPC authentication/verifier entries */ @@ -424,8 +470,13 @@ static uint32_t *rpc_add_credentials(uint32_t *p) static int rpc_check_reply(struct packet *pkt, uint32_t rpc_id) { struct rpc_reply rpc; + void *p; - memcpy(&rpc, pkt->data, sizeof(rpc)); + p = nfs_packet_read(pkt, sizeof(rpc)); + if (!p) + return -EINVAL; + + memcpy(&rpc, p, sizeof(rpc)); if (ntoh32(rpc.id) != rpc_id) return -EAGAIN; @@ -537,6 +588,8 @@ static int rpc_lookup_req(struct nfs_priv *npriv, uint32_t prog, uint32_t ver) uint32_t data[16]; struct packet *nfs_packet; uint32_t port; + void *p; + int ret; data[0] = 0; data[1] = 0; /* auth credential */ data[2] = 0; data[3] = 0; /* auth verifier */ @@ -549,7 +602,13 @@ static int rpc_lookup_req(struct nfs_priv *npriv, uint32_t prog, uint32_t ver) if (IS_ERR(nfs_packet)) return PTR_ERR(nfs_packet); - port = ntoh32(net_read_uint32(nfs_packet->data + sizeof(struct rpc_reply))); + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } + + port = ntoh32(net_read_uint32(p)); nfs_free_packet(nfs_packet); @@ -560,6 +619,11 @@ static int rpc_lookup_req(struct nfs_priv *npriv, uint32_t prog, uint32_t ver) } return port; + +err_free_packet: + nfs_free_packet(nfs_packet); + + return ret; } static uint32_t *nfs_add_uint32(uint32_t *p, uint32_t val) @@ -672,8 +736,10 @@ static int nfs_fattr3_to_stat(uint32_t *p, struct inode *inode) return 0; } -static uint32_t *nfs_read_post_op_attr(uint32_t *p, struct inode *inode) +static int nfs_read_post_op_attr(struct packet *nfs_packet, struct inode *inode) { + void *p; + /* * union post_op_attr switch (bool attributes_follow) { * case TRUE: @@ -683,12 +749,18 @@ static uint32_t *nfs_read_post_op_attr(uint32_t *p, struct inode *inode) * }; */ - if (ntoh32(net_read_uint32(p++))) { + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) + return -EINVAL; + + if (ntoh32(net_read_uint32(p))) { + p = nfs_packet_read(nfs_packet, 21 * sizeof(uint32_t)); + if (!p) + return -EINVAL; nfs_fattr3_to_stat(p, inode); - p += 21; } - return p; + return 0; } /* @@ -700,6 +772,7 @@ static int nfs_mount_req(struct nfs_priv *npriv) uint32_t *p, status; int len; int pathlen; + int ret; struct packet *nfs_packet; pathlen = strlen(npriv->path); @@ -722,31 +795,50 @@ static int nfs_mount_req(struct nfs_priv *npriv) if (IS_ERR(nfs_packet)) return PTR_ERR(nfs_packet); - p = (void *)nfs_packet->data + sizeof(struct rpc_reply); - /* * Theoretically the error status is one of MNT3ERR_..., but the NFS * constants are identical. */ - status = ntoh32(net_read_uint32(p++)); - if (status != NFS3_OK) { - int ret; - pr_err("Mounting failed: %s\n", nfserrstr(status, &ret)); - return ret; + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; } - npriv->rootfh.size = ntoh32(net_read_uint32(p++)); + status = ntoh32(net_read_uint32(p)); + if (status != NFS3_OK) { + pr_err("Mounting failed: %s\n", nfserrstr(status, &ret)); + goto err_free_packet; + } + + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } + + npriv->rootfh.size = ntoh32(net_read_uint32(p)); if (npriv->rootfh.size > NFS3_FHSIZE) { printf("%s: file handle too big: %lu\n", __func__, (unsigned long)npriv->rootfh.size); - nfs_free_packet(nfs_packet); - return -EIO; + ret = -EIO; + goto err_free_packet; } + + p = nfs_packet_read(nfs_packet, npriv->rootfh.size); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } + memcpy(npriv->rootfh.data, p, npriv->rootfh.size); + ret = 0; + +err_free_packet: nfs_free_packet(nfs_packet); - return 0; + return ret; } /* @@ -787,6 +879,7 @@ static int nfs_lookup_req(struct nfs_priv *npriv, struct nfs_fh *fh, uint32_t data[1024]; uint32_t *p, status; int len; + int ret = 0; struct packet *nfs_packet; /* @@ -827,29 +920,50 @@ static int nfs_lookup_req(struct nfs_priv *npriv, struct nfs_fh *fh, if (IS_ERR(nfs_packet)) return PTR_ERR(nfs_packet); - p = (void *)nfs_packet->data + sizeof(struct rpc_reply); - status = ntoh32(net_read_uint32(p++)); - if (status != NFS3_OK) { - int ret; - pr_err("Lookup failed: %s\n", nfserrstr(status, &ret)); - return ret; + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; } - ninode->fh.size = ntoh32(net_read_uint32(p++)); + status = ntoh32(net_read_uint32(p)); + if (status != NFS3_OK) { + pr_err("Lookup failed: %s\n", nfserrstr(status, &ret)); + goto err_free_packet; + } + + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } + + ninode->fh.size = ntoh32(net_read_uint32(p)); if (ninode->fh.size > NFS3_FHSIZE) { - nfs_free_packet(nfs_packet); debug("%s: file handle too big: %u\n", __func__, ninode->fh.size); - return -EIO; + ret = -EIO; + goto err_free_packet; } + + p = nfs_packet_read(nfs_packet, ninode->fh.size); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } + memcpy(ninode->fh.data, p, ninode->fh.size); - p += DIV_ROUND_UP(ninode->fh.size, 4); - nfs_read_post_op_attr(p, inode); + nfs_read_align(nfs_packet, 4); + nfs_read_post_op_attr(nfs_packet, inode); + + ret = 0; + +err_free_packet: nfs_free_packet(nfs_packet); - return 0; + return ret; } /* @@ -862,7 +976,8 @@ static void *nfs_readdirattr_req(struct nfs_priv *npriv, struct nfs_dir *dir) uint32_t *p, status; int len; struct packet *nfs_packet; - void *buf; + void *buf = NULL; + int ret; /* * struct READDIR3args { @@ -917,37 +1032,43 @@ static void *nfs_readdirattr_req(struct nfs_priv *npriv, struct nfs_dir *dir) if (IS_ERR(nfs_packet)) return NULL; - p = (void *)nfs_packet->data + sizeof(struct rpc_reply); - status = ntoh32(net_read_uint32(p++)); + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } + + status = ntoh32(net_read_uint32(p)); if (status != NFS3_OK) { pr_err("Readdir failed: %s\n", nfserrstr(status, NULL)); - return NULL; + ret = -EIO; + goto err_free_packet; } - p = nfs_read_post_op_attr(p, NULL); + ret = nfs_read_post_op_attr(nfs_packet, NULL); + if (ret) + goto err_free_packet; /* update cookieverf */ - memcpy(dir->cookieverf, p, NFS3_COOKIEVERFSIZE); - p += NFS3_COOKIEVERFSIZE / 4; - - len = (void *)nfs_packet->data + nfs_packet->len - (void *)p; - if (!len) { - printf("%s: huh, no payload left\n", __func__); - nfs_free_packet(nfs_packet); - return NULL; + p = nfs_packet_read(nfs_packet, NFS3_COOKIEVERFSIZE); + if (!p) { + ret = -EINVAL; + goto err_free_packet; } - buf = xzalloc(len); + memcpy(dir->cookieverf, p, NFS3_COOKIEVERFSIZE); - memcpy(buf, p, len); - - nfs_free_packet(nfs_packet); + buf = nfs_packet_memdup_rest(nfs_packet, &len); xdr_init(&dir->stream, buf, len); - /* now xdr points to dirlist3 res.resok.reply */ + ret = 0; - return buf; + /* now xdr points to dirlist3 res.resok.reply */ +err_free_packet: + nfs_free_packet(nfs_packet); + + return ret ? NULL : buf; } /* @@ -1000,19 +1121,37 @@ static int nfs_read_req(struct file_priv *priv, uint64_t offset, if (IS_ERR(nfs_packet)) return PTR_ERR(nfs_packet); - p = (void *)nfs_packet->data + sizeof(struct rpc_reply); - status = ntoh32(net_read_uint32(p++)); - if (status != NFS3_OK) { - pr_err("Read failed: %s\n", nfserrstr(status, &ret)); - return ret; + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; } - p = nfs_read_post_op_attr(p, NULL); + status = ntoh32(net_read_uint32(p)); + if (status != NFS3_OK) { + pr_err("Read failed: %s\n", nfserrstr(status, &ret)); + goto err_free_packet; + } + + ret = nfs_read_post_op_attr(nfs_packet, NULL); + if (ret) { + ret = -EINVAL; + goto err_free_packet; + } + + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } rlen = ntoh32(net_read_uint32(p)); - /* skip over count */ - p += 1; + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } eof = ntoh32(net_read_uint32(p)); @@ -1020,18 +1159,23 @@ static int nfs_read_req(struct file_priv *priv, uint64_t offset, * skip over eof and count embedded in the representation of data * assuming it equals rlen above. */ - p += 2; + nfs_packet_read(nfs_packet, sizeof(uint32_t)); if (readlen && !rlen && !eof) { - nfs_free_packet(nfs_packet); - return -EIO; + ret = -EIO; + goto err_free_packet; } + p = nfs_packet_read(nfs_packet, rlen); + kfifo_put(priv->fifo, (char *)p, rlen); + ret = 0; + +err_free_packet: nfs_free_packet(nfs_packet); - return 0; + return ret; } static void nfs_handler(void *ctx, char *p, unsigned len) @@ -1043,6 +1187,7 @@ static void nfs_handler(void *ctx, char *p, unsigned len) packet = xmalloc(sizeof(*packet) + len); memcpy(packet->data, pkt, len); packet->len = len; + packet->pos = 0; list_add_tail(&packet->list, &npriv->packets); } @@ -1066,6 +1211,7 @@ static int nfs_readlink_req(struct nfs_priv *npriv, struct nfs_fh *fh, uint32_t data[1024]; uint32_t *p, status; uint32_t len; + int ret; struct packet *nfs_packet; /* @@ -1100,29 +1246,43 @@ static int nfs_readlink_req(struct nfs_priv *npriv, struct nfs_fh *fh, if (IS_ERR(nfs_packet)) return PTR_ERR(nfs_packet); - p = (void *)nfs_packet->data + sizeof(struct rpc_reply); - status = ntoh32(net_read_uint32(p++)); - if (status != NFS3_OK) { - int ret; - pr_err("Readlink failed: %s\n", nfserrstr(status, &ret)); - return ret; + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; } - p = nfs_read_post_op_attr(p, NULL); + status = ntoh32(net_read_uint32(p)); + if (status != NFS3_OK) { + pr_err("Readlink failed: %s\n", nfserrstr(status, &ret)); + goto err_free_packet; + } + + nfs_read_post_op_attr(nfs_packet, NULL); + + p = nfs_packet_read(nfs_packet, sizeof(uint32_t)); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } len = ntoh32(net_read_uint32(p)); /* new path length */ - len = min_t(unsigned int, len, - nfs_packet->len - sizeof(struct rpc_reply) - sizeof(uint32_t)); - - p++; + p = nfs_packet_read(nfs_packet, len); + if (!p) { + ret = -EINVAL; + goto err_free_packet; + } *target = xzalloc(len + 1); memcpy(*target, p, len); + ret = 0; + +err_free_packet: nfs_free_packet(nfs_packet); - return 0; + return ret; } static const char *nfs_get_link(struct dentry *dentry, struct inode *inode) -- 2.47.3
