From babddc72a9468884ce1a23db3c3d54b0afa299f0 Mon Sep 17 00:00:00 2001 From: Bryan Schumaker Date: Wed, 20 Oct 2010 15:44:29 -0400 Subject: NFS: decode_dirent should use an xdr_stream Convert nfs*xdr.c to use an xdr stream in decode_dirent. This will prevent a kernel oops that has been occuring when reading a vmapped page. Signed-off-by: Bryan Schumaker Signed-off-by: Trond Myklebust diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index fd30f18..88cbcda 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -171,7 +171,7 @@ struct nfs_cache_array { #define MAX_READDIR_ARRAY ((PAGE_SIZE - sizeof(struct nfs_cache_array)) / sizeof(struct nfs_cache_array_entry)) -typedef __be32 * (*decode_dirent_t)(__be32 *, struct nfs_entry *, int); +typedef __be32 * (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, int); typedef struct { struct file *file; struct page *page; @@ -357,13 +357,11 @@ error: /* Fill in an entry based on the xdr code stored in desc->page */ static -int xdr_decode(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, __be32 **ptr) +int xdr_decode(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, struct xdr_stream *stream) { - __be32 *p = *ptr; - p = desc->decode(p, entry, desc->plus); + __be32 *p = desc->decode(stream, entry, desc->plus); if (IS_ERR(p)) return PTR_ERR(p); - *ptr = p; entry->fattr->time_start = desc->timestamp; entry->fattr->gencount = desc->gencount; @@ -438,10 +436,23 @@ out: /* Perform conversion from xdr to cache array */ static void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, - struct page *xdr_page, struct page *page) + struct page *xdr_page, struct page *page, unsigned int buflen) { + struct xdr_stream stream; + struct xdr_buf buf; __be32 *ptr = kmap(xdr_page); - while (xdr_decode(desc, entry, &ptr) == 0) { + + buf.head->iov_base = xdr_page; + buf.head->iov_len = buflen; + buf.tail->iov_len = 0; + buf.page_base = 0; + buf.page_len = 0; + buf.buflen = buf.head->iov_len; + buf.len = buf.head->iov_len; + + xdr_init_decode(&stream, &buf, ptr); + + while (xdr_decode(desc, entry, &stream) == 0) { if (nfs_readdir_add_to_array(entry, page) == -1) break; if (desc->plus == 1) @@ -458,6 +469,7 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct file *file = desc->file; struct nfs_cache_array *array; int status = 0; + unsigned int array_size = 1; entry.prev_cookie = 0; entry.cookie = *desc->dir_cookie; @@ -476,9 +488,10 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, goto out_release_array; do { status = nfs_readdir_xdr_filler(xdr_page, desc, &entry, file, inode); + if (status < 0) break; - nfs_readdir_page_filler(desc, &entry, xdr_page, page); + nfs_readdir_page_filler(desc, &entry, xdr_page, page, array_size * PAGE_SIZE); } while (array->eof_index < 0 && array->size < MAX_READDIR_ARRAY); put_page(xdr_page); diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index c961bc9..74b0155 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -181,15 +181,15 @@ extern void nfs_destroy_directcache(void); /* nfs2xdr.c */ extern int nfs_stat_to_errno(int); extern struct rpc_procinfo nfs_procedures[]; -extern __be32 * nfs_decode_dirent(__be32 *, struct nfs_entry *, int); +extern __be32 *nfs_decode_dirent(struct xdr_stream *, struct nfs_entry *, int); /* nfs3xdr.c */ extern struct rpc_procinfo nfs3_procedures[]; -extern __be32 *nfs3_decode_dirent(__be32 *, struct nfs_entry *, int); +extern __be32 *nfs3_decode_dirent(struct xdr_stream *, struct nfs_entry *, int); /* nfs4xdr.c */ #ifdef CONFIG_NFS_V4 -extern __be32 *nfs4_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus); +extern __be32 *nfs4_decode_dirent(struct xdr_stream *, struct nfs_entry *entry, int plus); #endif #ifdef CONFIG_NFS_V4_1 extern const u32 nfs41_maxread_overhead; diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c index 79c7438..0210c75 100644 --- a/fs/nfs/nfs2xdr.c +++ b/fs/nfs/nfs2xdr.c @@ -500,25 +500,56 @@ err_unmap: goto out; } +static void print_overflow_msg(const char *func, const struct xdr_stream *xdr) +{ + dprintk("nfs: %s: prematurely hit end of receive buffer. " + "Remaining buffer length is %tu words.\n", + func, xdr->end - xdr->p); +} + __be32 * -nfs_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus) +nfs_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, int plus) { - if (!*p++) { - if (!*p) + __be32 *p; + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; + if (!ntohl(*p++)) { + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; + if (!ntohl(*p++)) return ERR_PTR(-EAGAIN); entry->eof = 1; return ERR_PTR(-EBADCOOKIE); } + p = xdr_inline_decode(xdr, 8); + if (unlikely(!p)) + goto out_overflow; + entry->ino = ntohl(*p++); entry->len = ntohl(*p++); + + p = xdr_inline_decode(xdr, entry->len + 4); + if (unlikely(!p)) + goto out_overflow; entry->name = (const char *) p; p += XDR_QUADLEN(entry->len); entry->prev_cookie = entry->cookie; entry->cookie = ntohl(*p++); - entry->eof = !p[0] && p[1]; + + p = xdr_inline_peek(xdr, 8); + if (p != NULL) + entry->eof = !p[0] && p[1]; + else + entry->eof = 0; return p; + +out_overflow: + print_overflow_msg(__func__, xdr); + return ERR_PTR(-EIO); } /* diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c index 52b2fda..d562c8d 100644 --- a/fs/nfs/nfs3xdr.c +++ b/fs/nfs/nfs3xdr.c @@ -100,6 +100,13 @@ static const umode_t nfs_type2fmt[] = { [NF3FIFO] = S_IFIFO, }; +static void print_overflow_msg(const char *func, const struct xdr_stream *xdr) +{ + dprintk("nfs: %s: prematurely hit end of receive buffer. " + "Remaining buffer length is %tu words.\n", + func, xdr->end - xdr->p); +} + /* * Common NFS XDR functions as inlines */ @@ -119,6 +126,29 @@ xdr_decode_fhandle(__be32 *p, struct nfs_fh *fh) return NULL; } +static inline __be32 * +xdr_decode_fhandle_stream(struct xdr_stream *xdr, struct nfs_fh *fh) +{ + __be32 *p; + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; + fh->size = ntohl(*p++); + + if (fh->size <= NFS3_FHSIZE) { + p = xdr_inline_decode(xdr, fh->size); + if (unlikely(!p)) + goto out_overflow; + memcpy(fh->data, p, fh->size); + return p + XDR_QUADLEN(fh->size); + } + return NULL; + +out_overflow: + print_overflow_msg(__func__, xdr); + return ERR_PTR(-EIO); +} + /* * Encode/decode time. */ @@ -241,6 +271,26 @@ xdr_decode_post_op_attr(__be32 *p, struct nfs_fattr *fattr) } static inline __be32 * +xdr_decode_post_op_attr_stream(struct xdr_stream *xdr, struct nfs_fattr *fattr) +{ + __be32 *p; + + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; + if (ntohl(*p++)) { + p = xdr_inline_decode(xdr, 84); + if (unlikely(!p)) + goto out_overflow; + p = xdr_decode_fattr(p, fattr); + } + return p; +out_overflow: + print_overflow_msg(__func__, xdr); + return ERR_PTR(-EIO); +} + +static inline __be32 * xdr_decode_pre_op_attr(__be32 *p, struct nfs_fattr *fattr) { if (*p++) @@ -616,19 +666,33 @@ err_unmap: } __be32 * -nfs3_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus) +nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, int plus) { + __be32 *p; struct nfs_entry old = *entry; - if (!*p++) { - if (!*p) + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; + if (!ntohl(*p++)) { + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; + if (!ntohl(*p++)) return ERR_PTR(-EAGAIN); entry->eof = 1; return ERR_PTR(-EBADCOOKIE); } + p = xdr_inline_decode(xdr, 12); + if (unlikely(!p)) + goto out_overflow; p = xdr_decode_hyper(p, &entry->ino); entry->len = ntohl(*p++); + + p = xdr_inline_decode(xdr, entry->len + 8); + if (unlikely(!p)) + goto out_overflow; entry->name = (const char *) p; p += XDR_QUADLEN(entry->len); entry->prev_cookie = entry->cookie; @@ -636,10 +700,17 @@ nfs3_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus) if (plus) { entry->fattr->valid = 0; - p = xdr_decode_post_op_attr(p, entry->fattr); + p = xdr_decode_post_op_attr_stream(xdr, entry->fattr); + if (IS_ERR(p)) + goto out_overflow_exit; /* In fact, a post_op_fh3: */ + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; if (*p++) { - p = xdr_decode_fhandle(p, entry->fh); + p = xdr_decode_fhandle_stream(xdr, entry->fh); + if (IS_ERR(p)) + goto out_overflow_exit; /* Ugh -- server reply was truncated */ if (p == NULL) { dprintk("NFS: FH truncated\n"); @@ -650,8 +721,18 @@ nfs3_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus) memset((u8*)(entry->fh), 0, sizeof(*entry->fh)); } - entry->eof = !p[0] && p[1]; + p = xdr_inline_peek(xdr, 8); + if (p != NULL) + entry->eof = !p[0] && p[1]; + else + entry->eof = 0; + return p; + +out_overflow: + print_overflow_msg(__func__, xdr); +out_overflow_exit: + return ERR_PTR(-EIO); } /* diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index d24a8e07..c58ea63 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -331,7 +331,7 @@ extern void nfs_free_seqid(struct nfs_seqid *seqid); extern const nfs4_stateid zero_stateid; /* nfs4xdr.c */ -extern __be32 *nfs4_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus); +extern __be32 *nfs4_decode_dirent(struct xdr_stream *, struct nfs_entry *entry, int plus); extern struct rpc_procinfo nfs4_procedures[]; struct nfs4_mount_data; diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c index 6ea5c93..a4919e9 100644 --- a/fs/nfs/nfs4xdr.c +++ b/fs/nfs/nfs4xdr.c @@ -3950,13 +3950,13 @@ static int decode_lock_denied (struct xdr_stream *xdr, struct file_lock *fl) __be32 *p; uint32_t namelen, type; - p = xdr_inline_decode(xdr, 32); + p = xdr_inline_decode(xdr, 32); /* read 32 bytes */ if (unlikely(!p)) goto out_overflow; - p = xdr_decode_hyper(p, &offset); + p = xdr_decode_hyper(p, &offset); /* read 2 8-byte long words */ p = xdr_decode_hyper(p, &length); - type = be32_to_cpup(p++); - if (fl != NULL) { + type = be32_to_cpup(p++); /* 4 byte read */ + if (fl != NULL) { /* manipulate file lock */ fl->fl_start = (loff_t)offset; fl->fl_end = fl->fl_start + (loff_t)length - 1; if (length == ~(uint64_t)0) @@ -3966,9 +3966,9 @@ static int decode_lock_denied (struct xdr_stream *xdr, struct file_lock *fl) fl->fl_type = F_RDLCK; fl->fl_pid = 0; } - p = xdr_decode_hyper(p, &clientid); - namelen = be32_to_cpup(p); - p = xdr_inline_decode(xdr, namelen); + p = xdr_decode_hyper(p, &clientid); /* read 8 bytes */ + namelen = be32_to_cpup(p); /* read 4 bytes */ /* have read all 32 bytes now */ + p = xdr_inline_decode(xdr, namelen); /* variable size field */ if (likely(p)) return -NFS4ERR_DENIED; out_overflow: @@ -5755,21 +5755,33 @@ static int nfs4_xdr_dec_reclaim_complete(struct rpc_rqst *rqstp, uint32_t *p, } #endif /* CONFIG_NFS_V4_1 */ -__be32 *nfs4_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus) +__be32 *nfs4_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, int plus) { uint32_t bitmap[2] = {0}; uint32_t len; - - if (!*p++) { - if (!*p) + __be32 *p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; + if (!ntohl(*p++)) { + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; + if (!ntohl(*p++)) return ERR_PTR(-EAGAIN); entry->eof = 1; return ERR_PTR(-EBADCOOKIE); } + p = xdr_inline_decode(xdr, 12); + if (unlikely(!p)) + goto out_overflow; entry->prev_cookie = entry->cookie; p = xdr_decode_hyper(p, &entry->cookie); entry->len = ntohl(*p++); + + p = xdr_inline_decode(xdr, entry->len + 4); + if (unlikely(!p)) + goto out_overflow; entry->name = (const char *) p; p += XDR_QUADLEN(entry->len); @@ -5782,29 +5794,54 @@ __be32 *nfs4_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus) len = ntohl(*p++); /* bitmap length */ if (len-- > 0) { + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; bitmap[0] = ntohl(*p++); if (len-- > 0) { + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; bitmap[1] = ntohl(*p++); p += len; } } + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; len = XDR_QUADLEN(ntohl(*p++)); /* attribute buffer length */ if (len > 0) { if (bitmap[0] & FATTR4_WORD0_RDATTR_ERROR) { bitmap[0] &= ~FATTR4_WORD0_RDATTR_ERROR; /* Ignore the return value of rdattr_error for now */ - p++; - len--; + p = xdr_inline_decode(xdr, 4); + if (unlikely(!p)) + goto out_overflow; } - if (bitmap[0] == 0 && bitmap[1] == FATTR4_WORD1_MOUNTED_ON_FILEID) + if (bitmap[0] == 0 && bitmap[1] == FATTR4_WORD1_MOUNTED_ON_FILEID) { + p = xdr_inline_decode(xdr, 8); + if (unlikely(!p)) + goto out_overflow; xdr_decode_hyper(p, &entry->ino); - else if (bitmap[0] == FATTR4_WORD0_FILEID) + } else if (bitmap[0] == FATTR4_WORD0_FILEID) { + p = xdr_inline_decode(xdr, 8); + if (unlikely(!p)) + goto out_overflow; xdr_decode_hyper(p, &entry->ino); - p += len; + } } - entry->eof = !p[0] && p[1]; + p = xdr_inline_peek(xdr, 8); + if (p != NULL) + entry->eof = !p[0] && p[1]; + else + entry->eof = 0; + return p; + +out_overflow: + print_overflow_msg(__func__, xdr); + return ERR_PTR(-EIO); } /* diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h index 5772b2c..ca0e8fd 100644 --- a/include/linux/nfs_xdr.h +++ b/include/linux/nfs_xdr.h @@ -1036,7 +1036,7 @@ struct nfs_rpc_ops { int (*pathconf) (struct nfs_server *, struct nfs_fh *, struct nfs_pathconf *); int (*set_capabilities)(struct nfs_server *, struct nfs_fh *); - __be32 *(*decode_dirent)(__be32 *, struct nfs_entry *, int plus); + __be32 *(*decode_dirent)(struct xdr_stream *, struct nfs_entry *, int plus); void (*read_setup) (struct nfs_read_data *, struct rpc_message *); int (*read_done) (struct rpc_task *, struct nfs_read_data *); void (*write_setup) (struct nfs_write_data *, struct rpc_message *); -- cgit v0.10.2