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main: prevent creating files longer than f_namemax

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Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
This commit is contained in:
Giuseppe Scrivano 2020-10-04 17:00:28 +02:00
parent 4725e0ba66
commit 573cfac0a6
No known key found for this signature in database
GPG Key ID: E4730F97F60286ED
2 changed files with 91 additions and 13 deletions
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93
main.c
View File

@ -145,7 +145,7 @@ open_by_handle_at (int mount_fd, struct file_handle *handle, int flags)
#define PRIVILEGED_OPAQUE_XATTR "trusted.overlay.opaque"
#define PRIVILEGED_ORIGIN_XATTR "trusted.overlay.origin"
#define OPAQUE_WHITEOUT ".wh..wh..opq"
#define WHITEOUT_MAX_LEN (sizeof (OPAQUE_WHITEOUT))
#define WHITEOUT_MAX_LEN (sizeof (".wh.")-1)
#if !defined FICLONE && defined __linux__
# define FICLONE _IOW (0x94, 9, int)
@ -3583,6 +3583,43 @@ do_getattr (fuse_req_t req, struct fuse_entry_param *e, struct ovl_node *node, i
return 0;
}
static int
do_statfs (struct ovl_data *lo, struct statvfs *sfs)
{
int ret, fd;
fd = get_first_layer (lo)->fd;
if (fd >= 0)
ret = fstatvfs (fd, sfs);
else
ret = statvfs (lo->mountpoint, sfs);
if (ret < 0)
return ret;
sfs->f_namemax -= WHITEOUT_MAX_LEN;
return 0;
}
static short
get_fs_namemax (struct ovl_data *lo)
{
static short namemax = 0;
if (namemax == 0)
{
struct statvfs sfs;
int ret;
ret = do_statfs (lo, &sfs);
/* On errors use a sane default. */
if (ret < 0)
namemax = 255 - WHITEOUT_MAX_LEN;
else
namemax = sfs.f_namemax;
}
return namemax;
}
static void
ovl_create (fuse_req_t req, fuse_ino_t parent, const char *name,
mode_t mode, struct fuse_file_info *fi)
@ -3591,12 +3628,19 @@ ovl_create (fuse_req_t req, fuse_ino_t parent, const char *name,
cleanup_close int fd = -1;
struct fuse_entry_param e;
struct ovl_node *node = NULL;
struct ovl_data *lo = ovl_data (req);
struct stat st;
if (UNLIKELY (ovl_debug (req)))
fprintf (stderr, "ovl_create(parent=%" PRIu64 ", name=%s)\n",
parent, name);
if (strlen (name) > get_fs_namemax (lo))
{
fuse_reply_err (req, ENAMETOOLONG);
return;
}
fi->flags = fi->flags | O_CREAT;
fd = ovl_do_open (req, parent, name, fi->flags, mode, &node, &st);
@ -3869,6 +3913,12 @@ ovl_link (fuse_req_t req, fuse_ino_t ino, fuse_ino_t newparent, const char *newn
if (UNLIKELY (ovl_debug (req)))
fprintf (stderr, "ovl_link(ino=%" PRIu64 "s, newparent=%" PRIu64 "s, newname=%s)\n", ino, newparent, newname);
if (strlen (newname) > get_fs_namemax (lo))
{
fuse_reply_err (req, ENAMETOOLONG);
return;
}
node = do_lookup_file (lo, ino, NULL);
if (node == NULL || node->whiteout)
{
@ -4008,6 +4058,12 @@ ovl_symlink (fuse_req_t req, const char *link, fuse_ino_t parent, const char *na
if (UNLIKELY (ovl_debug (req)))
fprintf (stderr, "ovl_symlink(link=%s, ino=%" PRIu64 "s, name=%s)\n", link, parent, name);
if (strlen (name) > get_fs_namemax (lo))
{
fuse_reply_err (req, ENAMETOOLONG);
return;
}
pnode = do_lookup_file (lo, parent, NULL);
if (pnode == NULL || pnode->whiteout)
{
@ -4411,9 +4467,17 @@ ovl_rename (fuse_req_t req, fuse_ino_t parent, const char *name,
unsigned int flags)
{
cleanup_lock int l = enter_big_lock ();
struct ovl_data *lo = ovl_data (req);
if (UNLIKELY (ovl_debug (req)))
fprintf (stderr, "ovl_rename(ino=%" PRIu64 "s, name=%s , ino=%" PRIu64 "s, name=%s)\n", parent, name, newparent, newname);
if (strlen (newname) > get_fs_namemax (lo))
{
fuse_reply_err (req, ENAMETOOLONG);
return;
}
if (flags & RENAME_EXCHANGE)
ovl_rename_exchange (req, parent, name, newparent, newname, flags);
else
@ -4423,27 +4487,17 @@ ovl_rename (fuse_req_t req, fuse_ino_t parent, const char *name,
static void
ovl_statfs (fuse_req_t req, fuse_ino_t ino)
{
int ret, fd;
int ret;
struct statvfs sfs;
struct ovl_data *lo = ovl_data (req);
if (UNLIKELY (ovl_debug (req)))
fprintf (stderr, "ovl_statfs(ino=%" PRIu64 "s)\n", ino);
fd = get_first_layer (lo)->fd;
if (fd >= 0)
ret = fstatvfs (fd, &sfs);
else
ret = statvfs (lo->mountpoint, &sfs);
ret = do_statfs (lo, &sfs);
if (ret < 0)
{
fuse_reply_err (req, errno);
return;
}
sfs.f_namemax -= WHITEOUT_MAX_LEN;
fuse_reply_statfs (req, &sfs);
}
@ -4555,6 +4609,12 @@ ovl_mknod (fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode, dev
fprintf (stderr, "ovl_mknod(ino=%" PRIu64 ", name=%s, mode=%d, rdev=%lu)\n",
parent, name, mode, rdev);
if (strlen (name) > get_fs_namemax (lo))
{
fuse_reply_err (req, ENAMETOOLONG);
return;
}
mode = mode & ~ctx->umask;
node = do_lookup_file (lo, parent, name);
@ -4665,6 +4725,13 @@ ovl_mkdir (fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode)
fprintf (stderr, "ovl_mkdir(ino=%" PRIu64 ", name=%s, mode=%d)\n",
parent, name, mode);
if (strlen (name) > get_fs_namemax (lo))
{
fuse_reply_err (req, ENAMETOOLONG);
return;
}
node = do_lookup_file (lo, parent, name);
if (node != NULL && !node->whiteout)
{

11
tests/fedora-installs.sh
View File

@ -188,3 +188,14 @@ mkdir merged/adir
touch -h -d "2020-01-02 10:11:12" merged/adir
stat --format "%y" merged/adir | grep "10:11:12"
stat --format "%x" merged/adir | grep "10:11:12"
upper_max_filename_len=$(stat -f -c %l upper)
merged_max_filename_len=$(stat -f -c %l merged)
test $merged_max_filename_len -lt $upper_max_filename_len
if touch merged/$(printf %${upper_max_filename_len}s | tr ' ' A}); then
exit 1
fi
touch merged/$(printf %${merged_max_filename_len}s | tr ' ' A})