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[PATCH] udev - safer string handling - part two

Browse Source 
As promised, here is the next round. We provide in addition to the
already used macros:

  strfieldcpy(to, from)
  strfieldcat(to, from)

the corresponding friends, if the size of the target is not known and
must be provided by the caller:

  strnfieldcpy(to, from, maxsize)
  strnfieldcat(to, from, maxsize)

and switch nearly all possibly unsafe users of strcat(), strncat(),
strcpy() and strncpy() to these safer macros.

The last known remaining issue seems the use of sprintf() and
snprintf(). I will take on it later today or tomorrow.
This commit is contained in:
kay.sievers@vrfy.org 2004-02-26 19:40:22 -08:00 committed by Greg KH
parent bef370d6eb
commit 831f800da3
3 changed files with 32 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
namedev.c
View File

@ -209,7 +209,9 @@ static int get_format_len(char **str)
return -1;
}
static void apply_format(struct udevice *udev, unsigned char *string, struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device)
static void apply_format(struct udevice *udev, char *string, size_t maxsize,
struct sysfs_class_device *class_dev,
struct sysfs_device *sysfs_device)
{
char temp[NAME_SIZE];
char temp1[NAME_SIZE];
@ -245,19 +247,19 @@ static void apply_format(struct udevice *udev, unsigned char *string, struct sys
case 'b':
if (strlen(udev->bus_id) == 0)
break;
strcat(pos, udev->bus_id);
strnfieldcat(pos, udev->bus_id, maxsize);
dbg("substitute bus_id '%s'", udev->bus_id);
break;
case 'k':
if (strlen(udev->kernel_name) == 0)
break;
strcat(pos, udev->kernel_name);
strnfieldcat(pos, udev->kernel_name, maxsize);
dbg("substitute kernel name '%s'", udev->kernel_name);
break;
case 'n':
if (strlen(udev->kernel_number) == 0)
break;
strcat(pos, udev->kernel_number);
strnfieldcat(pos, udev->kernel_number, maxsize);
dbg("substitute kernel number '%s'", udev->kernel_number);
break;
case 'm':
@ -287,11 +289,11 @@ static void apply_format(struct udevice *udev, unsigned char *string, struct sys
}
}
if (pos3) {
strcat(pos, pos3);
strnfieldcat(pos, pos3, maxsize);
dbg("substitute part of result string '%s'", pos3);
}
} else {
strcat(pos, udev->program_result);
strnfieldcat(pos, udev->program_result, maxsize);
dbg("substitute result string '%s'", udev->program_result);
}
break;
@ -302,20 +304,20 @@ static void apply_format(struct udevice *udev, unsigned char *string, struct sys
dbg("sysfa attribute '%s' not found", attr);
break;
}
strcpy(pos, tmpattr->value);
strnfieldcpy(pos, tmpattr->value, maxsize);
dbg("substitute sysfs value '%s'", tmpattr->value);
} else {
dbg("missing attribute");
}
break;
case '%':
strcat(pos, "%");
strnfieldcat(pos, "%", maxsize);
break;
default:
dbg("unknown substitution type '%%%c'", c);
break;
}
strcat(pos, tail);
strnfieldcat(pos, tail, maxsize);
}
}
@ -462,7 +464,7 @@ static int execute_program(char *path, char *value, int len)
strncpy(value, buffer, len);
pos = value + strlen(value)-1;
if (pos[0] == '\n')
pos[0] = '\0';
pos[0] = '\0';
dbg("result is '%s'", value);
}
}
@ -733,7 +735,8 @@ static int match_rule(struct config_device *dev, struct sysfs_class_device *clas
/* execute external program */
if (dev->program[0] != '\0') {
dbg("check " FIELD_PROGRAM);
apply_format(udev, dev->program, class_dev, sysfs_device);
apply_format(udev, dev->program, sizeof(dev->program),
class_dev, sysfs_device);
if (execute_program(dev->program, udev->program_result, NAME_SIZE) != 0) {
dbg(FIELD_PROGRAM " returned nozero");
goto try_parent;
@ -825,8 +828,10 @@ int namedev_name_device(struct sysfs_class_device *class_dev, struct udevice *ud
found:
/* substitute placeholder */
apply_format(udev, udev->name, class_dev, sysfs_device);
apply_format(udev, udev->symlink, class_dev, sysfs_device);
apply_format(udev, udev->name, sizeof(udev->name),
class_dev, sysfs_device);
apply_format(udev, udev->symlink, sizeof(udev->symlink),
class_dev, sysfs_device);
udev->partitions = dev->partitions;
done:
perm = find_perm(udev->name);

14
udev.h
View File

@ -64,7 +64,19 @@ do { \
#define strfieldcat(to, from) \
do { \
to[sizeof(to)-1] = '\0'; \
strncat(to, from, sizeof(to) - strlen(to) -1); \
strncat(to, from, sizeof(to) - strlen(to)-1); \
} while (0)
#define strnfieldcpy(to, from, maxsize) \
do { \
to[maxsize-1] = '\0'; \
strncpy(to, from, maxsize-1); \
} while (0)
#define strnfieldcat(to, from, maxsize) \
do { \
to[maxsize-1] = '\0'; \
strncat(to, from, maxsize - strlen(to)-1); \
} while (0)
extern int udev_add_device(char *path, char *subsystem, int fake);

2
udev_config.c
View File

@ -81,7 +81,7 @@ static void init_variables(void)
#define set_var(_name, _var) \
if (strcasecmp(variable, _name) == 0) { \
dbg_parse("%s = '%s'", _name, value); \
strncpy(_var, value, sizeof(_var)); \
strnfieldcpy(_var, value, sizeof(_var));\
}
#define set_bool(_name, _var) \