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authorNiels de Vos <ndevos@redhat.com>2014-03-27 20:34:44 +0100
committerAnand Avati <avati@redhat.com>2014-04-21 10:25:21 -0700
commit20e317011af7c0f075819bf0648b225f6dc42350 (patch)
tree35576dbeb6202d529e4a8c0a3ae8faa168299a59
parent2da51737c49f7917a974bdf9e6e566307583ad16 (diff)
fuse: prevent READDIR(P) from writing to much data to /dev/fuse
In an environment with mixed architectures (32-bit servers, 64-bit client), it is possible that the on-wire Reply on a READDIR(P) procedure contains more direntries than the client can fit in the maximum size that the fuse-request indicated. A direntry is a dynamically sized structure, because the structure contains the name of the entry. The client sends a maximum size in the READDIR(P) Call to the server, and the server uses this size to limit the number of direntries to return. In case the server can pack more direntries in the requested maximum size (due to alignment differences between the architectures), it can happen that the client unpacks the list of direntries into a buffer that exceeds the maximum size that was given in the initial fuse-request. This change introduces a check for the maximum requested size of the fuse-response in fuse_readdir_cbk() and fuse_readdirp_cbk(). When the conversion from gluster-direntries to the fuse-direntry format takes place, the maximum size is checked, and the 'extra' direntries are discarded. The next readdir()/getdents() that is done, will fetch the just discarded direntries again. In addition to this bugfix, some extra logging in send_fuse_iov() and send_fuse_data() has been added to help diagnosing similar issues. Change-Id: If2eecfcdf9c248f3820035601446d2c89ff9d1a1 BUG: 1074023 Signed-off-by: Niels de Vos <ndevos@redhat.com> Reviewed-on: http://review.gluster.org/7278 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Xavier Hernandez <xhernandez@datalab.es> Reviewed-by: Anand Avati <avati@redhat.com>
-rw-r--r--xlators/mount/fuse/src/fuse-bridge.c60
1 files changed, 46 insertions, 14 deletions
diff --git a/xlators/mount/fuse/src/fuse-bridge.c b/xlators/mount/fuse/src/fuse-bridge.c
index cbf256e..fd44c4f 100644
--- a/xlators/mount/fuse/src/fuse-bridge.c
+++ b/xlators/mount/fuse/src/fuse-bridge.c
@@ -186,6 +186,8 @@ send_fuse_iov (xlator_t *this, fuse_in_header_t *finh, struct iovec *iov_out,
fouh->unique = finh->unique;
res = writev (priv->fd, iov_out, count);
+ gf_log ("glusterfs-fuse", GF_LOG_TRACE, "writev() result %d/%d %s",
+ res, fouh->len, res == -1 ? strerror (errno) : "");
if (res == -1)
return errno;
@@ -215,13 +217,19 @@ send_fuse_data (xlator_t *this, fuse_in_header_t *finh, void *data, size_t size)
{
struct fuse_out_header fouh = {0, };
struct iovec iov_out[2];
+ int ret = 0;
fouh.error = 0;
iov_out[0].iov_base = &fouh;
iov_out[1].iov_base = data;
iov_out[1].iov_len = size;
- return send_fuse_iov (this, finh, iov_out, 2);
+ ret = send_fuse_iov (this, finh, iov_out, 2);
+ if (ret != 0)
+ gf_log ("glusterfs-fuse", GF_LOG_ERROR, "send_fuse_iov() "
+ "failed: %s", strerror (ret));
+
+ return ret;
}
#define send_fuse_obj(this, finh, obj) \
@@ -2524,6 +2532,7 @@ fuse_readdir_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
fuse_state_t *state = NULL;
fuse_in_header_t *finh = NULL;
int size = 0;
+ int max_size = 0;
char *buf = NULL;
gf_dirent_t *entry = NULL;
struct fuse_dirent *fde = NULL;
@@ -2549,16 +2558,23 @@ fuse_readdir_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
frame->root->unique, op_ret, state->size, state->off);
list_for_each_entry (entry, &entries->list, list) {
- size += FUSE_DIRENT_ALIGN (FUSE_NAME_OFFSET +
- strlen (entry->d_name));
+ max_size += FUSE_DIRENT_ALIGN (FUSE_NAME_OFFSET +
+ strlen (entry->d_name));
+
+ if (max_size > state->size) {
+ /* we received to many entries to fit in the request */
+ max_size -= FUSE_DIRENT_ALIGN (FUSE_NAME_OFFSET +
+ strlen (entry->d_name));
+ break;
+ }
}
- if (size <= 0) {
- send_fuse_data (this, finh, 0, 0);
- goto out;
- }
+ if (max_size <= 0) {
+ send_fuse_data (this, finh, 0, 0);
+ goto out;
+ }
- buf = GF_CALLOC (1, size, gf_fuse_mt_char);
+ buf = GF_CALLOC (1, max_size, gf_fuse_mt_char);
if (!buf) {
gf_log ("glusterfs-fuse", GF_LOG_DEBUG,
"%"PRIu64": READDIR => -1 (%s)", frame->root->unique,
@@ -2572,6 +2588,9 @@ fuse_readdir_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
fde = (struct fuse_dirent *)(buf + size);
gf_fuse_fill_dirent (entry, fde, priv->enable_ino32);
size += FUSE_DIRENT_SIZE (fde);
+
+ if (size == max_size)
+ break;
}
send_fuse_data (this, finh, buf, size);
@@ -2625,6 +2644,7 @@ fuse_readdirp_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
{
fuse_state_t *state = NULL;
fuse_in_header_t *finh = NULL;
+ int max_size = 0;
int size = 0;
char *buf = NULL;
gf_dirent_t *entry = NULL;
@@ -2650,16 +2670,24 @@ fuse_readdirp_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
frame->root->unique, op_ret, state->size, state->off);
list_for_each_entry (entry, &entries->list, list) {
- size += FUSE_DIRENT_ALIGN (FUSE_NAME_OFFSET_DIRENTPLUS +
- strlen (entry->d_name));
+ max_size += FUSE_DIRENT_ALIGN (FUSE_NAME_OFFSET_DIRENTPLUS +
+ strlen (entry->d_name));
+
+ if (max_size > state->size) {
+ /* we received to many entries to fit in the reply */
+ max_size -= FUSE_DIRENT_ALIGN (
+ FUSE_NAME_OFFSET_DIRENTPLUS +
+ strlen (entry->d_name));
+ break;
+ }
}
- if (size <= 0) {
+ if (max_size <= 0) {
send_fuse_data (this, finh, 0, 0);
goto out;
}
- buf = GF_CALLOC (1, size, gf_fuse_mt_char);
+ buf = GF_CALLOC (1, max_size, gf_fuse_mt_char);
if (!buf) {
gf_log ("glusterfs-fuse", GF_LOG_DEBUG,
"%"PRIu64": READDIRP => -1 (%s)", frame->root->unique,
@@ -2682,7 +2710,7 @@ fuse_readdirp_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
size += FUSE_DIRENTPLUS_SIZE (fde);
if (!entry->inode)
- continue;
+ goto next_entry;
entry->d_stat.ia_blksize = this->ctx->page_size;
gf_fuse_stat2attr (&entry->d_stat, &feo->attr, priv->enable_ino32);
@@ -2690,7 +2718,7 @@ fuse_readdirp_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
linked_inode = inode_link (entry->inode, state->fd->inode,
entry->d_name, &entry->d_stat);
if (!linked_inode)
- continue;
+ goto next_entry;
inode_lookup (linked_inode);
@@ -2708,6 +2736,10 @@ fuse_readdirp_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
calc_timeout_sec (priv->attribute_timeout);
feo->attr_valid_nsec =
calc_timeout_nsec (priv->attribute_timeout);
+
+next_entry:
+ if (size == max_size)
+ break;
}
send_fuse_data (this, finh, buf, size);