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Merge pull request #581 from trapexit/ioctl

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fix FS_IOC_{GET,SET}{FLAGS,VERSION} ioctl calls
This commit is contained in:
trapexit 2019-02-17 13:11:57 -05:00 committed by GitHub
commit e8622fdd64
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6 changed files with 132 additions and 27 deletions
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12
libfuse/include/fuse.h
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@ -505,8 +505,13 @@ struct fuse_operations {
*
* Introduced in version 2.8
*/
int (*ioctl) (const char *, int cmd, void *arg,
struct fuse_file_info *, unsigned int flags, void *data);
int (*ioctl) (const char *fusepath,
int cmd,
void *arg,
struct fuse_file_info *ffi,
unsigned int flags,
void *data,
uint32_t *out_bufsz);
/**
* Poll for IO readiness events
@ -884,7 +889,8 @@ int fuse_fs_removexattr(struct fuse_fs *fs, const char *path,
int fuse_fs_bmap(struct fuse_fs *fs, const char *path, size_t blocksize,
uint64_t *idx);
int fuse_fs_ioctl(struct fuse_fs *fs, const char *path, int cmd, void *arg,
struct fuse_file_info *fi, unsigned int flags, void *data);
struct fuse_file_info *fi, unsigned int flags,
void *data, uint32_t *out_bufsz);
int fuse_fs_poll(struct fuse_fs *fs, const char *path,
struct fuse_file_info *fi, struct fuse_pollhandle *ph,
unsigned *reventsp);

10
libfuse/lib/fuse.c
View File

@ -2202,7 +2202,8 @@ int fuse_fs_removexattr(struct fuse_fs *fs, const char *path, const char *name)
}
int fuse_fs_ioctl(struct fuse_fs *fs, const char *path, int cmd, void *arg,
struct fuse_file_info *fi, unsigned int flags, void *data)
struct fuse_file_info *fi, unsigned int flags,
void *data, uint32_t *out_size)
{
fuse_get_context()->private_data = fs->user_data;
if (fs->op.ioctl) {
@ -2210,7 +2211,7 @@ int fuse_fs_ioctl(struct fuse_fs *fs, const char *path, int cmd, void *arg,
fprintf(stderr, "ioctl[%llu] 0x%x flags: 0x%x\n",
(unsigned long long) fi->fh, cmd, flags);
return fs->op.ioctl(path, cmd, arg, fi, flags, data);
return fs->op.ioctl(path, cmd, arg, fi, flags, data, out_size);
} else
return -ENOSYS;
}
@ -3896,13 +3897,14 @@ static void fuse_lib_bmap(fuse_req_t req, fuse_ino_t ino, size_t blocksize,
static void fuse_lib_ioctl(fuse_req_t req, fuse_ino_t ino, int cmd, void *arg,
struct fuse_file_info *llfi, unsigned int flags,
const void *in_buf, size_t in_bufsz,
size_t out_bufsz)
size_t out_bufsz_)
{
struct fuse *f = req_fuse_prepare(req);
struct fuse_intr_data d;
struct fuse_file_info fi;
char *path, *out_buf = NULL;
int err;
uint32_t out_bufsz = out_bufsz_;
err = -EPERM;
if (flags & FUSE_IOCTL_UNRESTRICTED)
@ -3931,7 +3933,7 @@ static void fuse_lib_ioctl(fuse_req_t req, fuse_ino_t ino, int cmd, void *arg,
fuse_prepare_interrupt(f, req, &d);
err = fuse_fs_ioctl(f->fs, path, cmd, arg, &fi, flags,
out_buf ?: (void *)in_buf);
out_buf ?: (void *)in_buf, &out_bufsz);
fuse_finish_interrupt(f, req, &d);
free_path(f, ino, path);

32
src/endian.hpp Normal file
View File

@ -0,0 +1,32 @@
/*
ISC License
Copyright (c) 2019, Antonio SJ Musumeci <trapexit@spawn.link>
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#pragma once
namespace endian
{
static
inline
bool
is_big(void)
{
const union { uint32_t i; char c[4]; } u = { 0x01000000 };
return u.c[0];
}
};

9
src/fs_base_ioctl.hpp
View File

@ -22,6 +22,15 @@
namespace fs
{
static
inline
int
ioctl(const int fd_,
const unsigned long request_)
{
return ::ioctl(fd_,request_);
}
static
inline
int

93
src/fuse_ioctl.cpp
View File

@ -16,6 +16,7 @@
#include "config.hpp"
#include "dirinfo.hpp"
#include "endian.hpp"
#include "errno.hpp"
#include "fileinfo.hpp"
#include "fs_base_close.hpp"
@ -35,30 +36,81 @@
using std::string;
using std::vector;
#ifndef FS_IOC_GETFLAGS
# define FS_IOC_GETFLAGS _IOR('f',1,long)
#endif
#ifndef FS_IOC_SETFLAGS
# define FS_IOC_SETFLAGS _IOW('f',2,long)
#endif
#ifndef FS_IOC_GETVERSION
# define FS_IOC_GETVERSION _IOR('v',1,long)
#endif
#ifndef FS_IOC_SETVERSION
# define FS_IOC_SETVERSION _IOW('v',2,long)
#endif
/*
There is a bug with FUSE and these ioctl commands. The regular
libfuse high level API assumes the output buffer size based on the
command and gives no control over this. FS_IOC_GETFLAGS and
FS_IOC_SETFLAGS however are defined as `long` when in fact it is an
`int`. On 64bit systems where long is 8 bytes this can lead to
libfuse telling the kernel to write 8 bytes and if the user only
allocated an integer then it will overwrite the 4 bytes after the
variable which could result in data corruption and/or crashes.
I've modified the API to allow changing of the output buffer
size. This fixes the issue on little endian systems because the
lower 4 bytes are the same regardless of what the user
allocated. However, on big endian systems thats not the case and it
is not possible to safely handle the situation.
https://lwn.net/Articles/575846/
*/
namespace l
{
static
int
ioctl(const int fd_,
const unsigned long cmd_,
void *data_)
ioctl(const int fd_,
const int cmd_,
void *data_,
uint32_t *out_bufsz_)
{
int rv;
rv = fs::ioctl(fd_,cmd_,data_);
switch(cmd_)
{
case FS_IOC_GETFLAGS:
case FS_IOC_SETFLAGS:
case FS_IOC_GETVERSION:
case FS_IOC_SETVERSION:
if(endian::is_big() && (sizeof(long) != sizeof(int)))
return -ENOTTY;
*out_bufsz_ = 4;
break;
}
rv = ((_IOC_DIR(cmd_) == _IOC_NONE) ?
fs::ioctl(fd_,cmd_) :
fs::ioctl(fd_,cmd_,data_));
return ((rv == -1) ? -errno : rv);
}
static
int
ioctl_file(fuse_file_info *ffi_,
const unsigned long cmd_,
void *data_)
ioctl_file(fuse_file_info *ffi_,
const int cmd_,
void *data_,
uint32_t *out_bufsz_)
{
FileInfo *fi = reinterpret_cast<FileInfo*>(ffi_->fh);
return l::ioctl(fi->fd,cmd_,data_);
return l::ioctl(fi->fd,cmd_,data_,out_bufsz_);
}
@ -72,8 +124,9 @@ namespace l
const Branches &branches_,
const uint64_t minfreespace_,
const char *fusepath_,
const unsigned long cmd_,
void *data_)
const int cmd_,
void *data_,
uint32_t *out_bufsz_)
{
int fd;
int rv;
@ -91,7 +144,7 @@ namespace l
if(fd == -1)
return -errno;
rv = l::ioctl(fd,cmd_,data_);
rv = l::ioctl(fd,cmd_,data_,out_bufsz_);
fs::close(fd);
@ -100,9 +153,10 @@ namespace l
static
int
ioctl_dir(fuse_file_info *ffi_,
const unsigned long cmd_,
void *data_)
ioctl_dir(fuse_file_info *ffi_,
const int cmd_,
void *data_,
uint32_t *out_bufsz_)
{
DirInfo *di = reinterpret_cast<DirInfo*>(ffi_->fh);
const fuse_context *fc = fuse_get_context();
@ -115,7 +169,8 @@ namespace l
config.minfreespace,
di->fusepath.c_str(),
cmd_,
data_);
data_,
out_bufsz_);
}
}
@ -127,12 +182,12 @@ namespace FUSE
void *arg_,
fuse_file_info *ffi_,
unsigned int flags_,
void *data_)
void *data_,
uint32_t *out_bufsz_)
{
if(flags_ & FUSE_IOCTL_DIR)
return l::ioctl_dir(ffi_,cmd_,data_);
return l::ioctl_dir(ffi_,cmd_,data_,out_bufsz_);
return l::ioctl_file(ffi_,cmd_,data_);
return l::ioctl_file(ffi_,cmd_,data_,out_bufsz_);
}
}

3
src/fuse_ioctl.hpp
View File

@ -26,5 +26,6 @@ namespace FUSE
void *arg_,
fuse_file_info *ffi_,
unsigned int flags_,
void *data_);
void *data_,
uint32_t *out_bufsz_);
}