Skip to content

[dfs][9pfs] fix: clamp server-controlled lengths to the received reply #11918

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
usualtreee wants to merge 1 commit into
base: master
Choose a base branch
from
+58 −4
Open

[dfs][9pfs] fix: clamp server-controlled lengths to the received reply #11918

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
62 changes: 58 additions & 4 deletions components/dfs/dfs_v1/filesystems/9pfs/dfs_9pfs.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -682,7 +682,7 @@ static ssize_t dfs_9pfs_read(struct dfs_file *fd, void *buf, size_t count)
{
int rc;
size_t tcount = 0;
rt_uint32_t max_count, set, size, got;
rt_uint32_t max_count, set, size, got, rx_size = 0;
struct p9_file *p9f = fd->vnode->data;
struct p9_connection *conn = p9f->connection;

Expand All @@ -704,10 +704,26 @@ static ssize_t dfs_9pfs_read(struct dfs_file *fd, void *buf, size_t count)
size = put_value32(conn, size, set);
put_tx_value32_of(conn, P9_MSG_SIZE, size);

if (!(rc = p9_transaction(conn, size, RT_NULL)))
if (!(rc = p9_transaction(conn, size, &rx_size)))
{
if (rx_size < P9_MSG_READ_DATA)
{
/* the reply does not even hold the count field */
tcount = p9_to_fs_err(P9_READ_UNEXPECTED_DATA);
break;
}

got = get_rx_value32_of(conn, P9_MSG_READ_COUNT);

/*
* Never trust the wire: the file data must fit into the data
* that was actually received.
*/
if (got > rx_size - P9_MSG_READ_DATA)
{
got = rx_size - P9_MSG_READ_DATA;
}

if (got == 0)
{
break;
Expand Down Expand Up @@ -824,7 +840,7 @@ static int dfs_9pfs_getdents(struct dfs_file *fd, struct dirent *dirp, uint32_t
{
int rc;
rt_uint64_t off;
rt_uint32_t ret, end, stat_size, size;
rt_uint32_t ret, end, stat_size, size, rx_size = 0;
struct p9_file *p9f = fd->vnode->data;
struct p9_connection *conn = p9f->connection;

Expand All @@ -849,23 +865,56 @@ static int dfs_9pfs_getdents(struct dfs_file *fd, struct dirent *dirp, uint32_t
size = put_value32(conn, size, fd->vnode->size);
put_tx_value32_of(conn, P9_MSG_SIZE, size);

if (!(rc = p9_transaction(conn, size, RT_NULL)))
if (!(rc = p9_transaction(conn, size, &rx_size)))
{
if (rx_size < P9_MSG_READ_DATA)
{
/* the reply does not even hold the count field */
rt_mutex_release(&conn->lock);
return -EIO;
}

ret = get_rx_value32_of(conn, P9_MSG_READ_COUNT);

/*
* Never trust the wire: the directory entries must fit into the
* data that was actually received.
*/
if (ret > rx_size - P9_MSG_READ_DATA)
{
ret = rx_size - P9_MSG_READ_DATA;
}
off = P9_MSG_READ_DATA - P9_MSG_STAT_SIZE;

for (int i = 0; (rt_int32_t)ret > 0; off += stat_size, ret -= stat_size, ++i)
{
if (ret < sizeof(rt_uint16_t))
{
/* not even the size field of the next record is left */
break;
}

/*
* size[2] type[2] dev[4] qid[1+4+8] mode[4] atime[4] mtime[4] length[8]
*/
stat_size = get_rx_value16_of(conn, off + P9_MSG_STAT_SIZE) + sizeof(rt_uint16_t);
if (stat_size > ret)
{
/* the record overruns the received data */
break;
}

if (i < fd->pos)
{
continue;
}

if (stat_size < P9_MSG_STAT_NAME_LEN - P9_MSG_STAT_SIZE + sizeof(rt_uint16_t))
{
/* the record cannot hold the fields up to the name length */
break;
}

if (get_rx_value16_of(conn, off + P9_MSG_STAT_TYPE) & P9_STAT_MODE_DIR)
{
dirp->d_type = DT_DIR;
Expand All @@ -886,6 +935,11 @@ static int dfs_9pfs_getdents(struct dfs_file *fd, struct dirent *dirp, uint32_t
* n_muid[4]
*/
dirp->d_namlen = get_rx_value16_of(conn, off + P9_MSG_STAT_NAME_LEN);
if (P9_MSG_STAT_NAME - P9_MSG_STAT_SIZE + dirp->d_namlen > stat_size)
{
/* the name overruns this record */
break;
}
dirp->d_reclen = (rt_uint16_t)sizeof(struct dirent);
rt_strncpy(dirp->d_name,
(void *)conn->rx_buffer + off + P9_MSG_STAT_NAME,
Expand Down
Loading