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server: Create anonymous file mappings in the config directory if the server directory is mounted noexec.

This commit is contained in:
Alexandre Julliard 2011-01-28 17:23:45 +01:00
parent 4e44e153c5
commit 8dbd06a1f8
1 changed files with 41 additions and 2 deletions
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43
server/mapping.c
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@ -26,6 +26,9 @@
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_MMAN_H
# include <sys/mman.h>
#endif
#include <unistd.h>
#include "ntstatus.h"
@ -161,13 +164,47 @@ static int grow_file( int unix_fd, file_pos_t new_size )
return 0;
}
/* check if the current directory allows exec mappings */
static int check_current_dir_for_exec(void)
{
int fd;
char tmpfn[] = "anonmap.XXXXXX";
void *ret = MAP_FAILED;
fd = mkstemps( tmpfn, 0 );
if (fd == -1) return 0;
if (grow_file( fd, 1 ))
{
ret = mmap( NULL, get_page_size(), PROT_READ | PROT_EXEC, MAP_PRIVATE, fd, 0 );
if (ret != MAP_FAILED) munmap( ret, get_page_size() );
}
close( fd );
unlink( tmpfn );
return (ret != MAP_FAILED);
}
/* create a temp file for anonymous mappings */
static int create_temp_file( file_pos_t size )
{
char tmpfn[16];
static int temp_dir_fd = -1;
char tmpfn[] = "anonmap.XXXXXX";
int fd;
sprintf( tmpfn, "anonmap.XXXXXX" ); /* create it in the server directory */
if (temp_dir_fd == -1)
{
temp_dir_fd = server_dir_fd;
if (!check_current_dir_for_exec())
{
/* the server dir is noexec, try the config dir instead */
fchdir( config_dir_fd );
if (check_current_dir_for_exec())
temp_dir_fd = config_dir_fd;
else /* neither works, fall back to server dir */
fchdir( server_dir_fd );
}
}
else if (temp_dir_fd != server_dir_fd) fchdir( temp_dir_fd );
fd = mkstemps( tmpfn, 0 );
if (fd != -1)
{
@ -179,6 +216,8 @@ static int create_temp_file( file_pos_t size )
unlink( tmpfn );
}
else file_set_error();
if (temp_dir_fd != server_dir_fd) fchdir( server_dir_fd );
return fd;
}