string_helpers: add kstrdup_quotable_file

Allocate a NULL-terminated file path with special characters escaped,
safe for logging.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
This commit is contained in:
Kees Cook 2016-04-20 15:46:25 -07:00 committed by James Morris
parent 0d0443288f
commit 21985319ad
2 changed files with 33 additions and 0 deletions

View file

@ -3,6 +3,8 @@
#include <linux/types.h>
struct file;
/* Descriptions of the types of units to
* print in */
enum string_size_units {
@ -70,5 +72,6 @@ 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);
char *kstrdup_quotable_file(struct file *file, gfp_t gfp);
#endif

View file

@ -10,6 +10,8 @@
#include <linux/export.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/limits.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
@ -596,3 +598,31 @@ char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp)
return quoted;
}
EXPORT_SYMBOL_GPL(kstrdup_quotable_cmdline);
/*
* Returns allocated NULL-terminated string containing pathname,
* with special characters escaped, able to be safely logged. If
* there is an error, the leading character will be "<".
*/
char *kstrdup_quotable_file(struct file *file, gfp_t gfp)
{
char *temp, *pathname;
if (!file)
return kstrdup("<unknown>", gfp);
/* We add 11 spaces for ' (deleted)' to be appended */
temp = kmalloc(PATH_MAX + 11, GFP_TEMPORARY);
if (!temp)
return kstrdup("<no_memory>", gfp);
pathname = file_path(file, temp, PATH_MAX + 11);
if (IS_ERR(pathname))
pathname = kstrdup("<too_long>", gfp);
else
pathname = kstrdup_quotable(pathname, gfp);
kfree(temp);
return pathname;
}
EXPORT_SYMBOL_GPL(kstrdup_quotable_file);