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linux-next/fs/binfmt_script.c
David Howells d7627467b7 Make do_execve() take a const filename pointer
Make do_execve() take a const filename pointer so that kernel_execve() compiles
correctly on ARM:

arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type

This also requires the argv and envp arguments to be consted twice, once for
the pointer array and once for the strings the array points to.  This is
because do_execve() passes a pointer to the filename (now const) to
copy_strings_kernel().  A simpler alternative would be to cast the filename
pointer in do_execve() when it's passed to copy_strings_kernel().

do_execve() may not change any of the strings it is passed as part of the argv
or envp lists as they are some of them in .rodata, so marking these strings as
const should be fine.

Further kernel_execve() and sys_execve() need to be changed to match.

This has been test built on x86_64, frv, arm and mips.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-17 18:07:43 -07:00

119 lines
2.8 KiB
C

/*
* linux/fs/binfmt_script.c
*
* Copyright (C) 1996 Martin von Löwis
* original #!-checking implemented by tytso.
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/binfmts.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/err.h>
#include <linux/fs.h>
static int load_script(struct linux_binprm *bprm,struct pt_regs *regs)
{
const char *i_arg, *i_name;
char *cp;
struct file *file;
char interp[BINPRM_BUF_SIZE];
int retval;
if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!') ||
(bprm->recursion_depth > BINPRM_MAX_RECURSION))
return -ENOEXEC;
/*
* This section does the #! interpretation.
* Sorta complicated, but hopefully it will work. -TYT
*/
bprm->recursion_depth++;
allow_write_access(bprm->file);
fput(bprm->file);
bprm->file = NULL;
bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
if ((cp = strchr(bprm->buf, '\n')) == NULL)
cp = bprm->buf+BINPRM_BUF_SIZE-1;
*cp = '\0';
while (cp > bprm->buf) {
cp--;
if ((*cp == ' ') || (*cp == '\t'))
*cp = '\0';
else
break;
}
for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++);
if (*cp == '\0')
return -ENOEXEC; /* No interpreter name found */
i_name = cp;
i_arg = NULL;
for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++)
/* nothing */ ;
while ((*cp == ' ') || (*cp == '\t'))
*cp++ = '\0';
if (*cp)
i_arg = cp;
strcpy (interp, i_name);
/*
* OK, we've parsed out the interpreter name and
* (optional) argument.
* Splice in (1) the interpreter's name for argv[0]
* (2) (optional) argument to interpreter
* (3) filename of shell script (replace argv[0])
*
* This is done in reverse order, because of how the
* user environment and arguments are stored.
*/
retval = remove_arg_zero(bprm);
if (retval)
return retval;
retval = copy_strings_kernel(1, &bprm->interp, bprm);
if (retval < 0) return retval;
bprm->argc++;
if (i_arg) {
retval = copy_strings_kernel(1, &i_arg, bprm);
if (retval < 0) return retval;
bprm->argc++;
}
retval = copy_strings_kernel(1, &i_name, bprm);
if (retval) return retval;
bprm->argc++;
bprm->interp = interp;
/*
* OK, now restart the process with the interpreter's dentry.
*/
file = open_exec(interp);
if (IS_ERR(file))
return PTR_ERR(file);
bprm->file = file;
retval = prepare_binprm(bprm);
if (retval < 0)
return retval;
return search_binary_handler(bprm,regs);
}
static struct linux_binfmt script_format = {
.module = THIS_MODULE,
.load_binary = load_script,
};
static int __init init_script_binfmt(void)
{
return register_binfmt(&script_format);
}
static void __exit exit_script_binfmt(void)
{
unregister_binfmt(&script_format);
}
core_initcall(init_script_binfmt);
module_exit(exit_script_binfmt);
MODULE_LICENSE("GPL");