From 1d15199152e1dfab18b86f855301ac7a0c597fab Mon Sep 17 00:00:00 2001 From: Ross Lagerwall Date: Sun, 27 Jul 2014 18:01:25 +0100 Subject: [PATCH] libnfs.c: Follow symlinks during path resolution Follow symlinks during path resolution. If the symlink points outside the mount, -ENOENT is returned. This is slightly different behavior from the in-kernel NFS client where symlinks pointing outside the mount get resolved to local paths. The algorithm for symlink resolution is simple and stupid. If a symlink is encountered, the path is rewritten and path resolution begins again from the root filehandle. A count is kept to prevent loops. This is not particularly efficient but it is good enough for now. Signed-off-by: Ross Lagerwall --- lib/libnfs.c | 170 +++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 145 insertions(+), 25 deletions(-) diff --git a/lib/libnfs.c b/lib/libnfs.c index 3115a68..2acd172 100644 --- a/lib/libnfs.c +++ b/lib/libnfs.c @@ -86,6 +86,7 @@ #include "libnfs-private.h" #define MAX_DIR_CACHE 128 +#define MAX_LINK_COUNT 40 struct nfsdir { struct nfs_fh3 fh; @@ -176,6 +177,7 @@ struct nfs_cb_data { struct nfs_context *nfs; struct nfsfh *nfsfh; char *saved_path, *path; + int link_count, no_follow; nfs_cb cb; void *private_data; @@ -205,6 +207,7 @@ struct nfs_mcb_data { }; static int nfs_lookup_path_async_internal(struct nfs_context *nfs, fattr3 *attr, struct nfs_cb_data *data, struct nfs_fh3 *fh); +static int nfs_normalize_path(struct nfs_context *nfs, char *path); void nfs_set_auth(struct nfs_context *nfs, struct AUTH *auth) { @@ -915,6 +918,97 @@ int nfs_mount_async(struct nfs_context *nfs, const char *server, const char *exp * Functions to first look up a path, component by component, and then finally call a specific function once * the filehandle for the final component is found. */ +static void nfs_lookup_path_2_cb(struct rpc_context *rpc, int status, void *command_data, void *private_data) +{ + struct nfs_cb_data *data = private_data; + struct nfs_context *nfs = data->nfs; + READLINK3res *res; + char *path, *newpath; + + assert(rpc->magic == RPC_CONTEXT_MAGIC); + + if (status == RPC_STATUS_ERROR) { + data->cb(-EFAULT, nfs, command_data, data->private_data); + free_nfs_cb_data(data); + return; + } + if (status == RPC_STATUS_CANCEL) { + data->cb(-EINTR, nfs, "Command was cancelled", data->private_data); + free_nfs_cb_data(data); + return; + } + + res = command_data; + if (res->status != NFS3_OK) { + rpc_set_error(nfs->rpc, "NFS: READLINK of %s failed with %s(%d)", data->saved_path, nfsstat3_to_str(res->status), nfsstat3_to_errno(res->status)); + data->cb(nfsstat3_to_errno(res->status), nfs, rpc_get_error(nfs->rpc), data->private_data); + free_nfs_cb_data(data); + return; + } + + path = res->READLINK3res_u.resok.data; + + /* Handle absolute paths, ensuring that the path lies within the + * export. */ + if (path[0] == '/') { + if (strstr(path, nfs->export) == path) { + char *ptr = path + strlen(nfs->export); + if (*ptr == '/') { + newpath = strdup(ptr); + } else if (*ptr == '\0') { + newpath = strdup("/"); + } else { + data->cb(-ENOENT, nfs, "Symbolic link points outside export", data->private_data); + free_nfs_cb_data(data); + return; + } + } else { + data->cb(-ENOENT, nfs, "Symbolic link points outside export", data->private_data); + free_nfs_cb_data(data); + return; + } + + if (!newpath) + goto nomem; + } else { + /* Handle relative paths, both the case where the current + * component is an intermediate component and when it is the + * final component. */ + if (data->path[0]) { + /* Since path points to a component and saved_path + * always starts with '/', path[-1] is valid. */ + data->path[-1] = '\0'; + newpath = malloc(strlen(data->saved_path) + strlen(path) + strlen(data->path) + 6); + if (!newpath) + goto nomem; + + sprintf(newpath, "%s/../%s/%s", data->saved_path, path, data->path); + } else { + newpath = malloc(strlen(data->saved_path) + strlen(path) + 5); + if (!newpath) + goto nomem; + + sprintf(newpath, "%s/../%s", data->saved_path, path); + } + } + free(data->saved_path); + data->saved_path = newpath; + + if (nfs_normalize_path(nfs, data->saved_path) != 0) { + data->cb(-ENOENT, nfs, "Symbolic link resolves to invalid path", data->private_data); + free_nfs_cb_data(data); + return; + } + + data->path = data->saved_path; + nfs_lookup_path_async_internal(nfs, NULL, data, &nfs->rootfh); + return; + +nomem: + data->cb(-ENOMEM, nfs, "Failed to allocate memory for path", data->private_data); + free_nfs_cb_data(data); +} + static void nfs_lookup_path_1_cb(struct rpc_context *rpc, int status, void *command_data, void *private_data) { struct nfs_cb_data *data = private_data; @@ -953,7 +1047,7 @@ static void nfs_lookup_path_1_cb(struct rpc_context *rpc, int status, void *comm nfs_lookup_path_async_internal(nfs, attr, data, &res->LOOKUP3res_u.resok.object); } -static int nfs_lookup_path_async_internal(struct nfs_context *nfs, fattr3 *attr _U_, struct nfs_cb_data *data, struct nfs_fh3 *fh) +static int nfs_lookup_path_async_internal(struct nfs_context *nfs, fattr3 *attr, struct nfs_cb_data *data, struct nfs_fh3 *fh) { char *path, *slash; LOOKUP3args args; @@ -964,6 +1058,31 @@ static int nfs_lookup_path_async_internal(struct nfs_context *nfs, fattr3 *attr path = data->path; slash = strchr(path, '/'); + + if (attr && attr->type == NF3LNK && (!data->no_follow || *path != '\0')) { + READLINK3args args; + + if (data->link_count++ >= MAX_LINK_COUNT) { + data->cb(-ELOOP, nfs, "Too many levels of symbolic links", data->private_data); + free_nfs_cb_data(data); + return -1; + } + + args.symlink = *fh; + + if (rpc_nfs3_readlink_async(nfs->rpc, nfs_lookup_path_2_cb, &args, data) != 0) { + rpc_set_error(nfs->rpc, "RPC error: Failed to send READLINK call for %s", data->path); + data->cb(-ENOMEM, nfs, rpc_get_error(nfs->rpc), data->private_data); + free_nfs_cb_data(data); + return -1; + } + + if (slash != NULL) { + *slash = '/'; + } + return 0; + } + if (slash != NULL) { /* Clear slash so that path is a zero terminated string for * the current path component. Set it back to '/' again later @@ -1147,7 +1266,7 @@ static void nfs_lookup_path_getattr_cb(struct rpc_context *rpc, int status, void nfs_lookup_path_async_internal(nfs, attr, data, &nfs->rootfh); } -static int nfs_lookuppath_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void *private_data, continue_func continue_cb, void *continue_data, void (*free_continue_data)(void *), int continue_int) +static int nfs_lookuppath_async(struct nfs_context *nfs, const char *path, int no_follow, nfs_cb cb, void *private_data, continue_func continue_cb, void *continue_data, void (*free_continue_data)(void *), int continue_int) { struct nfs_cb_data *data; struct GETATTR3args args; @@ -1172,6 +1291,7 @@ static int nfs_lookuppath_async(struct nfs_context *nfs, const char *path, nfs_c data->free_continue_data = free_continue_data; data->continue_int = continue_int; data->private_data = private_data; + data->no_follow = no_follow; if (path[0] == '/') { data->saved_path = strdup(path); } else { @@ -1327,7 +1447,7 @@ static int nfs_stat_continue_internal(struct nfs_context *nfs, fattr3 *attr _U_, int nfs_stat_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void *private_data) { - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_stat_continue_internal, NULL, NULL, 0) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_stat_continue_internal, NULL, NULL, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -1430,7 +1550,7 @@ static int nfs_stat64_continue_internal(struct nfs_context *nfs, fattr3 *attr _U int nfs_stat64_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void *private_data) { - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_stat64_continue_internal, NULL, NULL, 0) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_stat64_continue_internal, NULL, NULL, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -1624,7 +1744,7 @@ static int nfs_open_continue_internal(struct nfs_context *nfs, fattr3 *attr _U_, int nfs_open_async(struct nfs_context *nfs, const char *path, int flags, nfs_cb cb, void *private_data) { - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_open_continue_internal, NULL, NULL, flags) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_open_continue_internal, NULL, NULL, flags) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -1651,7 +1771,7 @@ static int nfs_chdir_continue_internal(struct nfs_context *nfs, fattr3 *attr _U_ int nfs_chdir_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void *private_data) { - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_chdir_continue_internal, NULL, NULL, 0) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_chdir_continue_internal, NULL, NULL, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -2432,7 +2552,7 @@ int nfs_truncate_async(struct nfs_context *nfs, const char *path, uint64_t lengt offset = length; - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_truncate_continue_internal, NULL, NULL, offset) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_truncate_continue_internal, NULL, NULL, offset) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -2522,7 +2642,7 @@ int nfs_mkdir_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void * *ptr = 0; /* new_path now points to the parent directory, and beyond the nul terminateor is the new directory to create */ - if (nfs_lookuppath_async(nfs, new_path, cb, private_data, nfs_mkdir_continue_internal, new_path, free, 0) != 0) { + if (nfs_lookuppath_async(nfs, new_path, 0, cb, private_data, nfs_mkdir_continue_internal, new_path, free, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path component"); return -1; } @@ -2609,7 +2729,7 @@ int nfs_rmdir_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void * *ptr = 0; /* new_path now points to the parent directory, and beyond the nul terminateor is the new directory to create */ - if (nfs_lookuppath_async(nfs, new_path, cb, private_data, nfs_rmdir_continue_internal, new_path, free, 0) != 0) { + if (nfs_lookuppath_async(nfs, new_path, 0, cb, private_data, nfs_rmdir_continue_internal, new_path, free, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -2859,7 +2979,7 @@ int nfs_create_async(struct nfs_context *nfs, const char *path, int flags, int m cb_data->mode = mode; /* new_path now points to the parent directory, and beyond the nul terminator is the new directory to create */ - if (nfs_lookuppath_async(nfs, cb_data->path, cb, private_data, nfs_create_continue_internal, cb_data, free_create_cb_data, 0) != 0) { + if (nfs_lookuppath_async(nfs, cb_data->path, 0, cb, private_data, nfs_create_continue_internal, cb_data, free_create_cb_data, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -2950,7 +3070,7 @@ int nfs_unlink_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void *ptr = 0; /* new_path now points to the parent directory, and beyond the nul terminateor is the new directory to create */ - if (nfs_lookuppath_async(nfs, new_path, cb, private_data, nfs_unlink_continue_internal, new_path, free, 0) != 0) { + if (nfs_lookuppath_async(nfs, new_path, 0, cb, private_data, nfs_unlink_continue_internal, new_path, free, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -3091,7 +3211,7 @@ int nfs_mknod_async(struct nfs_context *nfs, const char *path, int mode, int dev cb_data->minor = minor(dev); /* data->path now points to the parent directory, and beyond the nul terminateor is the new directory to create */ - if (nfs_lookuppath_async(nfs, cb_data->path, cb, private_data, nfs_mknod_continue_internal, cb_data, free_mknod_cb_data, 0) != 0) { + if (nfs_lookuppath_async(nfs, cb_data->path, 0, cb, private_data, nfs_mknod_continue_internal, cb_data, free_mknod_cb_data, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -3511,7 +3631,7 @@ int nfs_opendir_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void } memset(nfsdir, 0, sizeof(struct nfsdir)); - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_opendir_continue_internal, nfsdir, free, 0) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_opendir_continue_internal, nfsdir, free, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -3719,7 +3839,7 @@ static int nfs_statvfs_continue_internal(struct nfs_context *nfs, fattr3 *attr _ int nfs_statvfs_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void *private_data) { - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_statvfs_continue_internal, NULL, NULL, 0) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_statvfs_continue_internal, NULL, NULL, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -3782,7 +3902,7 @@ static int nfs_readlink_continue_internal(struct nfs_context *nfs, fattr3 *attr int nfs_readlink_async(struct nfs_context *nfs, const char *path, nfs_cb cb, void *private_data) { - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_readlink_continue_internal, NULL, NULL, 0) != 0) { + if (nfs_lookuppath_async(nfs, path, 1, cb, private_data, nfs_readlink_continue_internal, NULL, NULL, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -3848,7 +3968,7 @@ static int nfs_chmod_continue_internal(struct nfs_context *nfs, fattr3 *attr _U_ int nfs_chmod_async(struct nfs_context *nfs, const char *path, int mode, nfs_cb cb, void *private_data) { - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_chmod_continue_internal, NULL, NULL, mode) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_chmod_continue_internal, NULL, NULL, mode) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -3969,7 +4089,7 @@ int nfs_chown_async(struct nfs_context *nfs, const char *path, int uid, int gid, chown_data->uid = uid; chown_data->gid = gid; - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_chown_continue_internal, chown_data, free, 0) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_chown_continue_internal, chown_data, free, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -4104,7 +4224,7 @@ int nfs_utimes_async(struct nfs_context *nfs, const char *path, struct timeval * memcpy(new_times, times, sizeof(struct timeval)*2); } - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_utimes_continue_internal, new_times, free, 0) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_utimes_continue_internal, new_times, free, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -4132,7 +4252,7 @@ int nfs_utime_async(struct nfs_context *nfs, const char *path, struct utimbuf *t new_times[1].tv_usec = 0; } - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_utimes_continue_internal, new_times, free, 0) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_utimes_continue_internal, new_times, free, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -4229,7 +4349,7 @@ static int nfs_access_continue_internal(struct nfs_context *nfs, fattr3 *attr _U int nfs_access_async(struct nfs_context *nfs, const char *path, int mode, nfs_cb cb, void *private_data) { - if (nfs_lookuppath_async(nfs, path, cb, private_data, nfs_access_continue_internal, NULL, NULL, mode) != 0) { + if (nfs_lookuppath_async(nfs, path, 0, cb, private_data, nfs_access_continue_internal, NULL, NULL, mode) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -4359,7 +4479,7 @@ int nfs_symlink_async(struct nfs_context *nfs, const char *oldpath, const char * return -1; } - if (nfs_lookuppath_async(nfs, symlink_data->newpathparent, cb, private_data, nfs_symlink_continue_internal, symlink_data, free_nfs_symlink_data, 0) != 0) { + if (nfs_lookuppath_async(nfs, symlink_data->newpathparent, 0, cb, private_data, nfs_symlink_continue_internal, symlink_data, free_nfs_symlink_data, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -4470,7 +4590,7 @@ static int nfs_rename_continue_1_internal(struct nfs_context *nfs, fattr3 *attr rename_data->olddir = data->fh; data->fh.data.data_val = NULL; - if (nfs_lookuppath_async(nfs, rename_data->newpath, data->cb, data->private_data, nfs_rename_continue_2_internal, rename_data, free_nfs_rename_data, 0) != 0) { + if (nfs_lookuppath_async(nfs, rename_data->newpath, 0, data->cb, data->private_data, nfs_rename_continue_2_internal, rename_data, free_nfs_rename_data, 0) != 0) { rpc_set_error(nfs->rpc, "RPC error: Failed to send LOOKUP call for %s", newpath); data->cb(-ENOMEM, nfs, rpc_get_error(nfs->rpc), data->private_data); free_nfs_cb_data(data); @@ -4531,7 +4651,7 @@ int nfs_rename_async(struct nfs_context *nfs, const char *oldpath, const char *n rename_data->newobject = ptr; - if (nfs_lookuppath_async(nfs, rename_data->oldpath, cb, private_data, nfs_rename_continue_1_internal, rename_data, free_nfs_rename_data, 0) != 0) { + if (nfs_lookuppath_async(nfs, rename_data->oldpath, 0, cb, private_data, nfs_rename_continue_1_internal, rename_data, free_nfs_rename_data, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } @@ -4633,7 +4753,7 @@ static int nfs_link_continue_1_internal(struct nfs_context *nfs, fattr3 *attr _U link_data->oldfh = data->fh; data->fh.data.data_val = NULL; - if (nfs_lookuppath_async(nfs, link_data->newpath, data->cb, data->private_data, nfs_link_continue_2_internal, link_data, free_nfs_link_data, 0) != 0) { + if (nfs_lookuppath_async(nfs, link_data->newpath, 0, data->cb, data->private_data, nfs_link_continue_2_internal, link_data, free_nfs_link_data, 0) != 0) { rpc_set_error(nfs->rpc, "RPC error: Failed to send LOOKUP call for %s", link_data->newpath); data->cb(-ENOMEM, nfs, rpc_get_error(nfs->rpc), data->private_data); free_nfs_cb_data(data); @@ -4682,7 +4802,7 @@ int nfs_link_async(struct nfs_context *nfs, const char *oldpath, const char *new link_data->newobject = ptr; - if (nfs_lookuppath_async(nfs, link_data->oldpath, cb, private_data, nfs_link_continue_1_internal, link_data, free_nfs_link_data, 0) != 0) { + if (nfs_lookuppath_async(nfs, link_data->oldpath, 0, cb, private_data, nfs_link_continue_1_internal, link_data, free_nfs_link_data, 0) != 0) { rpc_set_error(nfs->rpc, "Out of memory: failed to start parsing the path components"); return -1; } -- 2.34.1