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file.cpp
1481 lines (1192 loc) · 55.7 KB
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file.cpp
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/*
Fakeroot Next Generation - run command with fake root privileges
This program is copyrighted. Copyright information is available at the
AUTHORS file at the root of the source tree for the fakeroot-ng project
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/ptrace.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
#include <limits.h>
#include <string.h>
#include "syscalls.h"
#include "file_lie.h"
#include "chroot.h"
#include "arch/platform.h"
// Helper function - fill in an override structure from a stat structure
static void stat_override_copy( const ptlib_stat *stat, stat_override *override )
{
override->dev=stat->dev;
override->inode=stat->ino;
override->uid=stat->uid;
override->gid=stat->gid;
override->dev_id=stat->rdev;
override->mode=stat->mode;
}
// Same function for stat, lstat and fstat
bool sys_stat( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
// Entering the syscall
state->state=pid_state::RETURN;
state->context_state[0]=ptlib_get_argument( pid, 2 ); // Store the pointer to the stat struct
dlog("stat64: " PID_F " stored pointer at %p\n", pid, (void*)state->context_state[0] );
// If the process is chrooted, we need to translate the file name
int real_sc=ptlib_get_syscall( pid );
if( ( real_sc==PREF_STAT || real_sc==PREF_LSTAT ) ) {
chroot_translate_param( pid, state, 1, real_sc!=PREF_LSTAT );
}
} else if( state->state==pid_state::RETURN ) {
// Returning from the syscall
int returncode=ptlib_get_retval( pid );
dlog("stat64: " PID_F " returned %x\n", pid, returncode);
try {
if( ptlib_success( pid, sc_num ) ) {
struct ptlib_stat ret;
struct stat_override override;
if( !ptlib_get_mem( pid, state->context_state[0], &ret, sizeof(ret) ) )
// Probably page fault - report the error
throw (int)errno;
if( get_map( ret.dev, ret.ino, &override ) ) {
bool ok=true;
ret.uid=override.uid;
ret.gid=override.gid;
if( S_ISBLK(override.mode) || S_ISCHR(override.mode) ) {
// Only turn regular files into devices
if( !S_ISREG( ret.mode ) )
ok=false;
ret.rdev=override.dev_id;
} else {
// If the override is not a device, and the types do not match, this is not a valid entry
ok=(S_IFMT&ret.mode)==(S_IFMT&override.mode);
}
// Override the u=x flag for directories, but not files
if( S_ISDIR(ret.mode) ) {
ret.mode=(ret.mode&(~(07700|S_IFMT))) | (override.mode&(07700|S_IFMT));
} else {
ret.mode=(ret.mode&(~(07600|S_IFMT))) | (override.mode&(07600|S_IFMT));
}
if( ok ) {
dlog("stat64: " PID_F " override dev=" DEV_F " inode=" INODE_F " mode=%o uid=" UID_F " gid=" GID_F "\n",
pid, ret.dev, ret.ino, ret.mode, ret.uid, ret.gid );
if( !ptlib_set_mem( pid, &ret, state->context_state[0], sizeof(struct stat) ) ) {
// Probably page fault - report the error
throw (int)errno;
// No need to remove the map - it is legitimate
}
} else {
dlog("stat64: " PID_F " dev=" DEV_F " inode=" INODE_F " override entry corrupt - removed\n", pid, ret.dev, ret.ino );
remove_map( ret.dev, ret.ino );
}
}
}
} catch( int error ) {
ptlib_set_error( pid, state->orig_sc, error );
}
state->state=pid_state::NONE;
}
return true;
}
#if HAVE_OPENAT
bool sys_fstatat64( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
// Entering the syscall
state->state=pid_state::RETURN;
chroot_translate_paramat( pid, state, ptlib_get_argument( pid, 1 ), 2, (ptlib_get_argument(pid, 4)&AT_SYMLINK_NOFOLLOW)!=0 );
state->context_state[0]=ptlib_get_argument( pid, 3 ); // Store the pointer to the stat struct
dlog("statat64: " PID_F " stored pointer at %p\n", pid, (void*)state->context_state[0] );
return true;
} else {
return sys_stat( sc_num, pid, state ); // Return code handling is the same as for the regular stat
}
}
#endif
static bool real_chmod( int sc_num, pid_t pid, pid_state *state, int mode_offset, int stat_function, int extra_flags=-1 )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
// First we stat the file to find out what we are up against (dev/inode etc.)
state->state=pid_state::REDIRECT2;
state->orig_sc=sc_num;
state->context_state[1]=ptlib_get_argument( pid, mode_offset+1 ); // Store the requested mode
state->context_state[0]=0; // syscall parts progress
ptlib_set_argument( pid, mode_offset+1, state->mem->get_mem() ); // where to store the stat result
// one anomaly handled with special case. ugly, but not worth the interface complication
if( extra_flags!=-1 ) {
// some of the functions require an extra flag after the usual parameters
dlog("real_chmod: set arg2 to %d\n", extra_flags);
ptlib_set_argument( pid, mode_offset+2, extra_flags );
}
ptlib_set_syscall( pid, stat_function );
} else if( state->state==pid_state::REDIRECT2 && state->context_state[0]==0 ) {
if( ptlib_success( pid, sc_num ) ) {
// Our stat succeeded
struct stat_override override;
struct ptlib_stat stat;
if( !ptlib_get_mem( pid, state->mem->get_mem(), &stat, sizeof( stat ) ) ) {
// This should never happen. We passed a buffer we are in charge of!
assert(0);
}
ptlib_save_state( pid, state->saved_state );
// Restore the original parameters to restart the actual chmod call
for( int i=1; i<=mode_offset; ++i )
ptlib_set_argument( pid, i, state->context_state[i+1] );
// one anomaly handled with special case. ugly, but not worth the interface complication
if( extra_flags!=-1 ) {
// some of the functions require an extra flag after the usual parameters
ptlib_set_argument( pid, mode_offset+2, extra_flags );
}
state->state=pid_state::REDIRECT1;
// Modify the chmod mode
mode_t mode=(mode_t)state->context_state[1];
mode&=~07000; // Clear the SUID etc. bits
if( S_ISDIR( stat.mode ) ) {
// The node in question is a directory
mode|=00700; // Make sure we have read, write and execute permission
} else {
// Node is not a directory
mode|=00600; // Set read and write for owner
}
ptlib_set_argument( pid, mode_offset+1, mode );
// Save the stuff we'll need in order to update the lies database
state->context_state[2]=stat.dev;
state->context_state[3]=stat.ino;
state->context_state[0]=1; // Mark this as the actual chmod call
// If we don't already have an entry for this file in the lies database, we will not have
// the complete stat struct later on to create it.
if( !get_map( stat.dev, stat.ino, &override ) ) {
// Create a lie that is identical to the actual file
stat_override_copy( &stat, &override );
set_map( &override );
}
return ptlib_generate_syscall( pid, state->orig_sc, state->mem->get_shared() );
} else {
// stat failed - return that failure to the caller as is
state->state=pid_state::NONE;
}
} else if( state->state==pid_state::REDIRECT2 && state->context_state[0]==1 ) {
if( ptlib_success( pid, sc_num ) ) {
// The chmod call succeeded - update the lies database
struct stat_override override;
if( !get_map( state->context_state[2], state->context_state[3], &override ) ) {
// We explicitly created this map not so long ago - something is wrong
// XXX What can we do except hope these are reasonable values
override.dev=state->context_state[2];
override.inode=state->context_state[3];
override.uid=0;
override.gid=0;
override.dev_id=0;
override.transient=true;
dlog("chmod: " PID_F " error (race?) getting override info for dev " DEV_F " inode " INODE_F "\n",
pid, (dev_t)state->context_state[2], (ptlib_inode_t)state->context_state[3] );
}
override.mode=(override.mode&~07777)|(((mode_t)state->context_state[1])&07777);
dlog("chmod: " PID_F " Setting override mode %o dev " DEV_F " inode " INODE_F "\n", pid, override.mode, override.dev,
override.inode );
set_map( &override );
ptlib_restore_state( pid, state->saved_state );
ptlib_set_retval( pid, 0 );
} else {
// We just need to restore the saved state but keep the chmod error code
int err=ptlib_get_error( pid, sc_num );
ptlib_restore_state( pid, state->saved_state );
ptlib_set_error( pid, sc_num, err );
}
state->state=pid_state::NONE;
} else {
dlog("chmod: " PID_F " unknown state %d\n", pid, state->state );
}
return true;
}
// The actual work is done by "real_chmod".
bool sys_chmod( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
chroot_translate_param( pid, state, 1, true );
state->context_state[2]=ptlib_get_argument( pid, 1 ); // Store the file name
}
return real_chmod( sc_num, pid, state, 1, PREF_STAT );
}
bool sys_fchmod( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
state->context_state[2]=ptlib_get_argument( pid, 1 ); // Store the file descriptor
}
return real_chmod( sc_num, pid, state, 1, PREF_FSTAT );
}
#if HAVE_OPENAT
bool sys_fchmodat( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
// XXX At some potential future date, Linux may implement AT_SYMLINK_NOFOLLOW, at which point
// this chroot translation will need to be reconsidered
chroot_translate_paramat( pid, state, ptlib_get_argument( pid, 1), 2, true );
state->context_state[2]=ptlib_get_argument( pid, 1 ); // Store the base dir fd
state->context_state[3]=ptlib_get_argument( pid, 2 ); // Store the file name
state->context_state[4]=ptlib_get_argument( pid, 4 ); // Store the flags
}
return real_chmod( sc_num, pid, state, 2, PREF_FSTATAT, 0 );
}
#endif
// context_state[0] and 1 should contain the desired uid and gid respectively
static bool real_chown( int sc_num, pid_t pid, pid_state *state, int own_offset, int stat_function, int extra_flags=-1 )
{
// XXX Do we handle the mode change following a chown (file and directory) correctly?
if( state->state==pid_state::NONE ) {
// Map this to a stat operation
ptlib_set_argument( pid, own_offset+1, state->mem->get_mem() );
if( extra_flags!=-1 ) {
ptlib_set_argument( pid, own_offset+2, extra_flags );
}
ptlib_set_syscall( pid, stat_function );
dlog("chown: " PID_F " redirected chown call to stat\n", pid );
state->state=pid_state::REDIRECT2;
} else if( state->state==pid_state::REDIRECT2 ) {
if( ptlib_success( pid, sc_num ) ) {
struct ptlib_stat stat;
struct stat_override override;
if( !ptlib_get_mem( pid, state->mem->get_mem(), &stat, sizeof( stat ) ) ) {
// This is a syscall we initiated, to a memory buffer we own. It should not have failed.
assert(0);
}
if( !get_map( stat.dev, stat.ino, &override ) ) {
dlog("chown: " PID_F " no override for file - create a new one\n", pid );
stat_override_copy( &stat, &override );
}
if( ((int)state->context_state[0])!=-1 )
override.uid=state->context_state[0];
if( ((int)state->context_state[1])!=-1 )
override.gid=state->context_state[1];
dlog("chown: " PID_F " changing owner of dev " DEV_F " inode " INODE_F "\n", pid, override.dev, override.inode );
set_map( &override );
} else {
dlog("chown: " PID_F " stat call failed with error %s\n", pid, strerror(ptlib_get_error(pid, sc_num)) );
}
state->state=pid_state::NONE;
}
return true;
}
bool sys_chown( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
state->context_state[0]=ptlib_get_argument(pid, 2);
state->context_state[1]=ptlib_get_argument(pid, 3);
chroot_translate_param( pid, state, 1, true );
}
return real_chown( sc_num, pid, state, 1, PREF_STAT );
}
bool sys_fchown( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
state->context_state[0]=ptlib_get_argument(pid, 2);
state->context_state[1]=ptlib_get_argument(pid, 3);
}
return real_chown( sc_num, pid, state, 1, PREF_FSTAT );
}
bool sys_lchown( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
state->context_state[0]=ptlib_get_argument(pid, 2);
state->context_state[1]=ptlib_get_argument(pid, 3);
chroot_translate_param( pid, state, 1, false );
}
return real_chown( sc_num, pid, state, 1, PREF_LSTAT );
}
#if HAVE_OPENAT
bool sys_fchownat( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
state->context_state[0]=ptlib_get_argument(pid, 3);
state->context_state[1]=ptlib_get_argument(pid, 4);
state->context_state[2]=ptlib_get_argument(pid, 5);
chroot_translate_paramat( pid, state, ptlib_get_argument( pid, 1 ), 2, (state->context_state[2]&AT_SYMLINK_NOFOLLOW)!=0 );
}
return real_chown( sc_num, pid, state, 2, PREF_FSTATAT, state->context_state[2] );
}
#endif
static bool real_mknod( int sc_num, pid_t pid, pid_state *state, int mode_offset, int stat_function, int extra_flags=-1 )
{
if( state->state==pid_state::NONE ) {
mode_t mode=(mode_t)state->context_state[0];
// Remove SUID and add user read and write
mode&=~07000;
mode|= 00600;
if( S_ISCHR(mode) || S_ISBLK(mode) ) {
dlog("mknod: " PID_F " tried to create %s device, turn to regular file\n", pid, S_ISCHR(mode) ? "character" : "block" );
mode=(mode&~S_IFMT) | S_IFREG;
}
ptlib_set_argument( pid, mode_offset+1, mode );
dlog("mknod: %d mode %o\n", pid, (unsigned int)state->context_state[1] );
state->state=pid_state::RETURN;
} else if( state->state==pid_state::RETURN ) {
if( ptlib_success( pid, sc_num ) ) {
// Need to call "stat" on the file to see what inode number it got
ptlib_save_state( pid, state->saved_state );
for( int i=0; i<mode_offset; ++i ) {
ptlib_set_argument( pid, i+1, state->context_state[2+i] ); // File name etc.
}
ptlib_set_argument( pid, mode_offset+1, state->mem->get_mem() ); // Struct stat
if( extra_flags!=-1 ) {
ptlib_set_argument( pid, mode_offset+2, extra_flags );
}
state->state=pid_state::REDIRECT1;
dlog("mknod: " PID_F " Actual node creation successful. Calling stat\n", pid );
return ptlib_generate_syscall( pid, stat_function, state->mem->get_shared() );
} else {
// Nothing to do if the call failed
dlog("mknod: " PID_F " call failed with error %s\n", pid, strerror(ptlib_get_error(pid, sc_num) ) );
}
} else if( state->state==pid_state::REDIRECT2 ) {
if( ptlib_success( pid, sc_num ) ) {
ptlib_stat stat;
stat_override override;
if( !ptlib_get_mem( pid, state->mem->get_mem(), &stat, sizeof(stat) ) ) {
// This should never happen. We passed a buffer we are in charge of!
assert(0);
}
// This file was, supposedly, just created. Even if it has an entry in the override DB, that entry is obsolete
stat_override_copy( &stat, &override );
// We created the file, it should have our uid/gid
override.uid=state->fsuid;
override.gid=state->fsgid;
dlog("mknod: " PID_F " registering the new device in the override DB dev " DEV_F " inode " INODE_F "\n", pid,
stat.dev, stat.ino );
mode_t mode=(mode_t)state->context_state[0];
if( S_ISCHR(mode) || S_ISBLK(mode) || (mode&07000)!=0) {
dlog("mknod: " PID_F " overriding the file type and/or mode\n", pid );
override.mode=(override.mode&~(S_IFMT|07000)) | (mode&(S_IFMT|07000));
override.dev_id=(dev_t)state->context_state[1];
}
// use the user read+write from the original, not the actual file
// XXX This code disregards the umask
override.mode&=~00600;
override.mode|= mode&00600;
set_map( &override );
} else {
// mknod succeeded, but stat failed?
dlog("mknod: " PID_F " stat failed. Leave override DB non-updated\n", pid );
}
ptlib_restore_state( pid, state->saved_state );
state->state=pid_state::NONE;
}
return true;
}
bool sys_mknod( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
chroot_translate_param( pid, state, 1, false );
state->context_state[0]=ptlib_get_argument( pid, 2 ); // Mode
state->context_state[1]=ptlib_get_argument( pid, 3 ); // Device ID
state->context_state[2]=ptlib_get_argument( pid, 1 ); // File name
}
return real_mknod( sc_num, pid, state, 1, PREF_STAT );
}
#if HAVE_OPENAT
bool sys_mknodat( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
chroot_translate_paramat( pid, state, ptlib_get_argument( pid, 1 ), 2, false );
state->context_state[0]=ptlib_get_argument( pid, 3 ); // Mode
state->context_state[1]=ptlib_get_argument( pid, 4 ); // Device ID
state->context_state[2]=ptlib_get_argument( pid, 1 ); // Base fd
state->context_state[3]=ptlib_get_argument( pid, 2 ); // File name
}
return real_mknod( sc_num, pid, state, 1, PREF_FSTATAT, 0 );
}
#endif
static bool real_open( int sc_num, pid_t pid, pid_state *state, int mode_argnum )
{
if( state->state==pid_state::NONE ) {
if( (state->context_state[0]&O_CREAT)!=0 ) {
// We are asking to create the file - make sure we give user read and write permission
state->context_state[1]=ptlib_get_argument( pid, mode_argnum );
mode_t mode=state->context_state[1];
// Remove SUID and add user read and write permission
mode&=~07000;
mode|= 00600;
if( mode!=state->context_state[1] ) {
ptlib_set_argument( pid, mode_argnum, mode );
}
}
state->state=pid_state::RETURN;
} else if( state->state==pid_state::RETURN ) {
// Did we request to create a new file?
if( (state->context_state[0]&O_CREAT)!=0 && ptlib_success(pid, sc_num) ) {
int fd=(long)ptlib_get_retval(pid);
dlog("open: " PID_F " opened fd %d, assume we actually created it\n", pid, fd );
ptlib_save_state( pid, state->saved_state );
state->state=pid_state::REDIRECT1;
// Call fstat to find out what we have
ptlib_set_argument( pid, 1, fd );
ptlib_set_argument( pid, 2, state->mem->get_mem() );
return ptlib_generate_syscall( pid, PREF_FSTAT, state->mem->get_shared() );
} else
state->state=pid_state::NONE;
} else if( state->state==pid_state::REDIRECT2 ) {
if( ptlib_success( pid, sc_num ) ) {
ptlib_stat stat;
stat_override override;
if( !ptlib_get_mem( pid, state->mem->get_mem(), &stat, sizeof( stat ) ) ) {
// This should never happen. We passed a buffer we are in charge of!
assert(0);
}
// XXX The test whether we just created a new file is not the most accurate in the world
// In particular, if the previous instance was deleted, this will misbehave
// Fixed: if the previous instance was deleted BY US, this should now be ok
// Still, /dev/null is routinely found in the map for no good reason due to this code
if( !get_map( stat.dev, stat.ino, &override ) || override.transient ) {
// If the map already exists, assume we did not create a new file and don't touch the owners
stat_override_copy( &stat, &override );
override.uid=state->fsuid;
override.gid=state->fsgid;
override.mode&=~07600;
override.mode|= state->context_state[1]&07600;
// XXX We are ignoring the umask here!
set_map( &override );
dlog("open: " PID_F " creating override for dev " DEV_F " inode " INODE_F "\n", pid, override.dev, override.inode);
} else {
dlog("open: " PID_F " map for dev " DEV_F " inode " INODE_F " already exists - doing nothing\n", pid, stat.dev, stat.ino );
}
} else {
dlog("open: " PID_F " fstat failed %s\n", pid, strerror( ptlib_get_error( pid, sc_num ) ) );
}
state->state=pid_state::NONE;
ptlib_restore_state( pid, state->saved_state );
}
return true;
}
bool sys_open( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
chroot_translate_param( pid, state, 1, true );
state->context_state[0]=ptlib_get_argument( pid, 2 ); //flags
}
return real_open( sc_num, pid, state, 3 );
}
#if HAVE_OPENAT
bool sys_openat( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
chroot_translate_paramat( pid, state, ptlib_get_argument( pid, 1 ), 2, true );
state->context_state[0]=ptlib_get_argument( pid, 3 ); //flags
}
return real_open( sc_num, pid, state, 4 );
}
#endif
static bool real_mkdir( int sc_num, pid_t pid, pid_state *state, int mode_offset, int stat_function, int extra_flags=-1 )
{
if( state->state==pid_state::NONE ) {
// Make sure user has rwx on the created directory
state->context_state[0]=ptlib_get_argument( pid, mode_offset+1 );
mode_t mode=state->context_state[0];
mode|= 00700;
if( mode!=state->context_state[0] ) {
// We did change the mode
ptlib_set_argument( pid, mode_offset+1, mode );
}
state->state=pid_state::RETURN;
} else if( state->state==pid_state::RETURN ) {
state->state=pid_state::NONE;
if( ptlib_success( pid, sc_num ) ) {
dlog("mkdir: " PID_F " succeeded. Call stat\n", pid );
ptlib_save_state( pid, state->saved_state );
// Perform a stat operation so we can know the directory's dev and inode
for( int i=1; i<=mode_offset; ++i )
ptlib_set_argument( pid, i, state->context_state[i] ); // The original mkdir arguments
ptlib_set_argument( pid, mode_offset+1, state->mem->get_mem() ); // stat structure
if( extra_flags!=-1 ) {
ptlib_set_argument( pid, mode_offset+2, extra_flags );
}
state->orig_sc=sc_num;
state->state=pid_state::REDIRECT1;
return ptlib_generate_syscall( pid, stat_function, state->mem->get_shared() );
} else {
// If mkdir failed, we don't have anything else to do.
dlog("mkdir: " PID_F " failed with error %s\n", pid, strerror(ptlib_get_error( pid, sc_num ) ) );
}
} else if( state->state==pid_state::REDIRECT2 ) {
if( ptlib_success( pid, sc_num ) ) {
ptlib_stat stat;
stat_override override;
if( !ptlib_get_mem( pid, state->mem->get_mem(), &stat, sizeof( stat ) ) ) {
// This should never happen. We passed a buffer we are in charge of!
assert(0);
}
// Since mkdir fails if the directory already exists, there is no point to check whether the override already exists
stat_override_copy( &stat, &override );
override.uid=state->fsuid;
override.gid=state->fsgid;
override.mode&=~00700;
override.mode|= state->context_state[0]&00700;
// XXX This code does not take the umask into account
dlog("mkdir: " PID_F " storing override for dev " DEV_F " inode " INODE_F "\n", pid, override.dev, override.inode);
set_map( &override );
} else {
dlog("mkdir: " PID_F " stat failed with error %s\n", pid, strerror(ptlib_get_error(pid, sc_num)));
}
ptlib_restore_state( pid, state->saved_state );
state->state=pid_state::NONE;
}
return true;
}
bool sys_mkdir( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
chroot_translate_param( pid, state, 1, true );
state->context_state[1]=ptlib_get_argument( pid, 1 ); // Directory name
if( log_level>0 ) {
char name[PATH_MAX];
ptlib_get_string( pid, state->context_state[0], name, sizeof(name) );
dlog("mkdir: %d creates %s\n", pid, name );
}
}
return real_mkdir( sc_num, pid, state, 1, PREF_STAT );
}
#if HAVE_OPENAT
bool sys_mkdirat( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
chroot_translate_paramat( pid, state, ptlib_get_argument( pid, 1 ), 2, true );
state->context_state[1]=ptlib_get_argument( pid, 1 ); // File descriptor
state->context_state[2]=ptlib_get_argument( pid, 2 ); // Directory name
if( log_level>0 ) {
char name[PATH_MAX];
ptlib_get_string( pid, state->context_state[2], name, sizeof(name) );
int fd=(int)state->context_state[1];
dlog("mkdirat: %d creates %s at %x\n", pid, name, fd );
}
}
return real_mkdir( sc_num, pid, state, 2, PREF_FSTATAT, 0 );
}
#endif
static bool real_symlink( int sc_num, pid_t pid, pid_state *state, int mode_offset, int stat_function, int extra_flags=-1 )
{
if( state->state==pid_state::NONE ) {
state->state=pid_state::RETURN;
} else if( state->state==pid_state::RETURN ) {
if( ptlib_success( pid, sc_num ) ) {
dlog("symlink: " PID_F " success. Call stat to mark uid/gid override\n", pid );
ptlib_save_state( pid, state->saved_state );
for( int i=0; i<mode_offset; ++i ) {
ptlib_set_argument( pid, i+1, state->context_state[i] ); // File name
}
ptlib_set_argument( pid, mode_offset+1, state->mem->get_mem() ); // stat structure
if( extra_flags!=-1 ) {
ptlib_set_argument( pid, mode_offset+2, extra_flags );
}
state->state=pid_state::REDIRECT1;
return ptlib_generate_syscall( pid, stat_function, state->mem->get_shared() );
} else {
dlog("symlink: " PID_F " failed with error %s\n", pid, strerror( ptlib_get_error(pid, sc_num) ) );
state->state=pid_state::NONE;
}
} else if( state->state==pid_state::REDIRECT2 ) {
if( ptlib_success( pid, sc_num ) ) {
ptlib_stat stat;
stat_override override;
if( !ptlib_get_mem( pid, state->mem->get_mem(), &stat, sizeof( stat ) ) ) {
// This should never happen. We passed a buffer we are in charge of!
assert(0);
}
// Make sure we got the right file
if( S_ISLNK(stat.mode) ) {
// No need to check the DB as we just created the file
stat_override_copy( &stat, &override );
override.uid=state->fsuid;
override.gid=state->fsgid;
dlog("symlink: " PID_F " set uid/gid override for dev " DEV_F " inode " INODE_F "\n", pid, override.dev, override.inode );
set_map( &override );
} else {
dlog("symlink: " PID_F " acutal file on disk is not a symlink. Type %o dev " DEV_F " inode " INODE_F "\n", pid, stat.mode, stat.dev,
stat.ino );
}
} else {
dlog("symlink: " PID_F " symlink succeeded, but stat failed with %s\n", pid, strerror(ptlib_get_error(pid, sc_num)));
}
ptlib_restore_state( pid, state->saved_state );
state->state=pid_state::NONE;
}
return true;
}
bool sys_symlink( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
chroot_translate_param( pid, state, 2, false );
state->context_state[0]=ptlib_get_argument( pid, 2 ); // new path
}
return real_symlink( sc_num, pid, state, 1, PREF_LSTAT );
}
#if HAVE_OPENAT
bool sys_symlinkat( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
chroot_translate_paramat( pid, state, ptlib_get_argument( pid, 2 ), 3, false );
state->context_state[0]=ptlib_get_argument( pid, 2 ); // dirfd
state->context_state[1]=ptlib_get_argument( pid, 3 ); // new path
}
return real_symlink( sc_num, pid, state, 2, PREF_FSTATAT, AT_SYMLINK_NOFOLLOW );
}
#endif
bool sys_getcwd( int sc_num, pid_t pid, pid_state *state )
{
if( state->state==pid_state::NONE ) {
PROC_MEM_LOCK();
state->state=pid_state::RETURN;
// If the process is chrooted, we need to translate the directory name
if( chroot_is_chrooted(state) ) {
// We don't want to report the real current directory, of course!
state->context_state[0]=ptlib_get_argument( pid, 1 ); // Buffer
state->context_state[1]=ptlib_get_argument( pid, 2 ); // Buffer len
// Perform the actual call into our buffer
ptlib_set_argument( pid, 1, state->mem->get_mem() );
ptlib_set_argument( pid, 2, PATH_MAX );
}
} else if( state->state==pid_state::RETURN ) {
state->state=pid_state::NONE;
if( ptlib_success( pid, sc_num ) && chroot_is_chrooted(state) ) {
// We are inside a chroot, and the call was successful
char buffer[PATH_MAX];
ptlib_get_string( pid, state->mem->get_mem(), buffer, sizeof(buffer) );
char tmp=buffer[state->root->length()];
buffer[state->root->length()]='\0';
char *ptr=buffer;
if( ( tmp=='/' || tmp=='\0' ) && *state->root==buffer ) {
// Current directory is inside the chroot jail - need to truncate the prefix
if( tmp=='/' ) {
ptr+=state->root->length();
*ptr=tmp;
} else {
// The current directory is the new root
strcpy( buffer, "/" );
}
} else {
// Current directory is outside of the jail - pass it to the program as is
buffer[state->root->length()]=tmp;
}
// Emulate the actual call
size_t len=strlen(ptr);
if( len<state->context_state[1] ) {
// Buffer is large enough
ptlib_set_string( pid, ptr, state->context_state[0] );
ptlib_set_retval( pid, len+1 );
} else {
// The buffer is not large enough
ptlib_set_error( pid, sc_num, ERANGE );
}
}
}
return true;
}
bool sys_munmap( int sc_num, pid_t pid, pid_state *state )
{
// XXX Does this work? We should never be called with REDIRECT1
if( state->state==pid_state::NONE || state->state==pid_state::REDIRECT1 ) {
if( state->state==pid_state::NONE ) {
// This is our first time entering this munmap
state->context_state[2]=0; // No state to restore
}
state->state=pid_state::RETURN;
state->context_state[0]=0; // 0 is the next start address to unmap, 1 is the new length
state->context_state[1]=0; // len=0 means we have no more mmaps to perform
// Is this an attempt to release one of the memory areas we own?
int_ptr start=ptlib_get_argument( pid, 1 );
int_ptr end=start+ptlib_get_argument( pid, 2 );
// If end wraps around then the kernel will fail this anyways
// Same goes if the page size is not aligned or the length is zero
if( start>end || (start%sysconf(_SC_PAGESIZE))!=0 || start==end )
// XXX We still need to fail this ourselves, just to make sure
return true;
// Put the lower of the two addreses in addr1
int_ptr addr1=state->mem->get_shared(), addr2=state->mem->get_mem();
size_t len1=static_mem_size, len2=shared_mem_size-ptlib_prepare_memory_len();
const char *name1="static", *name2="shared";
if( addr1>addr2 ) {
int_ptr tmp=addr1;
addr1=addr2;
addr2=tmp;
size_t tmplen=len1;
len1=len2;
len2=tmplen;
const char *tmpname=name1;
name1=name2;
name2=tmpname;
}
state->state=pid_state::REDIRECT2;
if( start<addr1 && end>addr1 ) {
// The unmap range covers the lower range
dlog("sys_munmap: " PID_F " tried to unmap range %p-%p, which conflicts with our %s range %p-%p\n",
pid, (void*)start, (void*)end, name1, (void*)addr1, (void*)(addr1+len1) );
if( end>addr1+len1 ) {
// There is an area to unmap above the lower range - mark it for a second syscall
state->context_state[0]=addr1+len1;
state->context_state[1]=end-state->context_state[0];
}
end=addr1;
} else if( start>=addr1 && start<addr1+len1 ) {
// The start pointer is inside the lower memory range
dlog("sys_munmap: " PID_F " tried to unmap range %p-%p, which conflicts with our %s range %p-%p\n",
pid, (void*)start, (void*)end, name1, (void*)addr1, (void*)(addr1+len1) );
start=addr1+len1;
} else if( start<addr2 && end>addr2 ) {
// The unmap area covers the upper memory range
dlog("sys_munmap: " PID_F " tried to unmap range %p-%p, which conflicts with our %s range %p-%p\n",
pid, (void*)start, (void*)end, name2, (void*)addr2, (void*)(addr2+len2) );
if( end>addr2+len2 ) {
// There is an area to unmap above the upper range - mark it for a second (third?) syscall
state->context_state[0]=addr2+len2;
state->context_state[1]=end-state->context_state[0];
}
end=addr2;
} else if( start>=addr2 && start<addr2+len2 ) {
// The start pointer is inside the upper memory range
dlog("sys_munmap: " PID_F " tried to unmap range %p-%p, which conflicts with our %s range %p-%p\n",
pid, (void*)start, (void*)end, name2, (void*)addr2, (void*)(addr2+len2) );
start=addr2+len2;
} else {
// The unmap range was a-ok. No need to touch the syscall at all
state->state=pid_state::RETURN;
return true;
}
// We had to change the parameters because of an overlap
ptlib_set_argument( pid, 1, start );
ptlib_set_argument( pid, 2, end-start );
} else if( state->state==pid_state::RETURN || state->state==pid_state::REDIRECT2 ) {
state->state=pid_state::NONE;
if( ptlib_success( pid, sc_num ) ) {
bool last=(state->context_state[1]==0);
// If we are not done yet, we will need to store this position and come back to it
if( state->context_state[2]==0 && !last ) {
ptlib_save_state( pid, state->saved_state );
state->context_state[2]=1;
}
if( !last ) {
// We split the munmap into several calls - there are more calls to perform
// Use REDIRECT3 rather than NONE so that strace won't see the extra call
state->state=pid_state::REDIRECT3;
ptlib_set_argument( pid, 1, state->context_state[0] );