Commit 0d044328 authored by Kees Cook's avatar Kees Cook Committed by James Morris
Browse files

string_helpers: add kstrdup_quotable_cmdline 



Provide an escaped (but readable: no inter-argument NULLs) commandline
safe for logging.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
parent b53f27e4

include/linux/string_helpers.h

+1 −0
Original line number Diff line number Diff line
@@ -69,5 +69,6 @@ static inline int string_escape_str_any_np(const char *src, char *dst, 
}



char *kstrdup_quotable(const char *src, gfp_t gfp);

char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp);



#endif

lib/string_helpers.c

+34 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/export.h>

#include <linux/ctype.h>

#include <linux/errno.h>

#include <linux/mm.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/string_helpers.h>
@@ -562,3 +563,36 @@ char *kstrdup_quotable(const char *src, gfp_t gfp) 
	return dst;

}

EXPORT_SYMBOL_GPL(kstrdup_quotable);



/*

 * Returns allocated NULL-terminated string containing process

 * command line, with inter-argument NULLs replaced with spaces,

 * and other special characters escaped.

 */

char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp)

{

	char *buffer, *quoted;

	int i, res;



	buffer = kmalloc(PAGE_SIZE, GFP_TEMPORARY);

	if (!buffer)

		return NULL;



	res = get_cmdline(task, buffer, PAGE_SIZE - 1);

	buffer[res] = '\0';



	/* Collapse trailing NULLs, leave res pointing to last non-NULL. */

	while (--res >= 0 && buffer[res] == '\0')

		;



	/* Replace inter-argument NULLs. */

	for (i = 0; i <= res; i++)

		if (buffer[i] == '\0')

			buffer[i] = ' ';



	/* Make sure result is printable. */

	quoted = kstrdup_quotable(buffer, gfp);

	kfree(buffer);

	return quoted;

}

EXPORT_SYMBOL_GPL(kstrdup_quotable_cmdline);