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udev/net-id: check all snprintf return values

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gcc-8 throws an error if it knows snprintf might truncate output and the
return value is ignored:
../src/udev/udev-builtin-net_id.c: In function 'dev_pci_slot':
../src/udev/udev-builtin-net_id.c:297:47: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size between 0 and 4095 [-Werror=format-truncation=]
                 snprintf(str, sizeof str, "%s/%s/address", slots, dent->d_name);
                                               ^~
../src/udev/udev-builtin-net_id.c:297:17: note: 'snprintf' output between 10 and 4360 bytes into a destination of size 4096
                 snprintf(str, sizeof str, "%s/%s/address", slots, dent->d_name);
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

Let's check all return values. This actually makes the code better, because there's
no point in trying to open a file when the name has been truncated, etc.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2018-02-23 11:12:19 +01:00
parent cc5bbdb274
commit 73fc96c8ac
2 changed files with 39 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/basic/stdio-util.h
View File

@ -27,9 +27,11 @@
#include "macro.h"
#define xsprintf(buf, fmt, ...) \
assert_message_se((size_t) snprintf(buf, ELEMENTSOF(buf), fmt, __VA_ARGS__) < ELEMENTSOF(buf), "xsprintf: " #buf "[] must be big enough")
#define snprintf_ok(buf, len, fmt, ...) \
((size_t) snprintf(buf, len, fmt, __VA_ARGS__) < (len))
#define xsprintf(buf, fmt, ...) \
assert_message_se(snprintf_ok(buf, ELEMENTSOF(buf), fmt, __VA_ARGS__), "xsprintf: " #buf "[] must be big enough")
#define VA_FORMAT_ADVANCE(format, ap) \
do { \

54
src/udev/udev-builtin-net_id.c
View File

@ -274,7 +274,9 @@ static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
if (!pci)
return -ENOENT;
snprintf(slots, sizeof slots, "%s/slots", udev_device_get_syspath(pci));
if (!snprintf_ok(slots, sizeof slots, "%s/slots", udev_device_get_syspath(pci)))
return -ENAMETOOLONG;
dir = opendir(slots);
if (!dir)
return -errno;
@ -292,12 +294,11 @@ static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
if (i < 1)
continue;
snprintf(str, sizeof str, "%s/%s/address", slots, dent->d_name);
if (read_one_line_file(str, &address) >= 0) {
if (snprintf_ok(str, sizeof str, "%s/%s/address", slots, dent->d_name) &&
read_one_line_file(str, &address) >= 0)
/* match slot address with device by stripping the function */
if (strneq(address, udev_device_get_sysname(names->pcidev), strlen(address)))
if (streq(address, udev_device_get_sysname(names->pcidev)))
hotplug_slot = i;
}
if (hotplug_slot > 0)
break;
@ -513,7 +514,6 @@ static int names_ccw(struct udev_device *dev, struct netnames *names) {
const char *bus_id, *subsys;
size_t bus_id_len;
size_t bus_id_start;
int rc;
assert(dev);
assert(names);
@ -555,9 +555,9 @@ static int names_ccw(struct udev_device *dev, struct netnames *names) {
bus_id += bus_id_start < bus_id_len ? bus_id_start : bus_id_len - 1;
/* Store the CCW bus-ID for use as network device name */
rc = snprintf(names->ccw_busid, sizeof(names->ccw_busid), "c%s", bus_id);
if (rc >= 0 && rc < (int)sizeof(names->ccw_busid))
if (snprintf_ok(names->ccw_busid, sizeof(names->ccw_busid), "c%s", bus_id))
names->type = NET_CCW;
return 0;
}
@ -670,7 +670,7 @@ static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool
if (err >= 0 && names.type == NET_CCW) {
char str[IFNAMSIZ];
if (snprintf(str, sizeof(str), "%s%s", prefix, names.ccw_busid) < (int)sizeof(str))
if (snprintf_ok(str, sizeof str, "%s%s", prefix, names.ccw_busid))
udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
goto out;
}
@ -680,7 +680,7 @@ static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool
if (err >= 0 && names.type == NET_VIO) {
char str[IFNAMSIZ];
if (snprintf(str, sizeof(str), "%s%s", prefix, names.vio_slot) < (int)sizeof(str))
if (snprintf_ok(str, sizeof str, "%s%s", prefix, names.vio_slot))
udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
goto out;
}
@ -690,7 +690,7 @@ static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool
if (err >= 0 && names.type == NET_PLATFORM) {
char str[IFNAMSIZ];
if (snprintf(str, sizeof(str), "%s%s", prefix, names.platform_path) < (int)sizeof(str))
if (snprintf_ok(str, sizeof str, "%s%s", prefix, names.platform_path))
udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
goto out;
}
@ -704,20 +704,20 @@ static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool
if (names.type == NET_PCI) {
char str[IFNAMSIZ];
if (names.pci_onboard[0])
if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard) < (int)sizeof(str))
if (names.pci_onboard[0] &&
snprintf_ok(str, sizeof str, "%s%s", prefix, names.pci_onboard))
udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", str);
if (names.pci_onboard_label)
if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard_label) < (int)sizeof(str))
if (names.pci_onboard_label &&
snprintf_ok(str, sizeof str, "%s%s", prefix, names.pci_onboard_label))
udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", str);
if (names.pci_path[0])
if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_path) < (int)sizeof(str))
if (names.pci_path[0] &&
snprintf_ok(str, sizeof str, "%s%s", prefix, names.pci_path))
udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
if (names.pci_slot[0])
if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_slot) < (int)sizeof(str))
if (names.pci_slot[0] &&
snprintf_ok(str, sizeof str, "%s%s", prefix, names.pci_slot))
udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
goto out;
}
@ -727,12 +727,12 @@ static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool
if (err >= 0 && names.type == NET_USB) {
char str[IFNAMSIZ];
if (names.pci_path[0])
if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.usb_ports) < (int)sizeof(str))
if (names.pci_path[0] &&
snprintf_ok(str, sizeof str, "%s%s%s", prefix, names.pci_path, names.usb_ports))
udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
if (names.pci_slot[0])
if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.usb_ports) < (int)sizeof(str))
if (names.pci_slot[0] &&
snprintf_ok(str, sizeof str, "%s%s%s", prefix, names.pci_slot, names.usb_ports))
udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
goto out;
}
@ -742,12 +742,12 @@ static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool
if (err >= 0 && names.type == NET_BCMA) {
char str[IFNAMSIZ];
if (names.pci_path[0])
if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.bcma_core) < (int)sizeof(str))
if (names.pci_path[0] &&
snprintf_ok(str, sizeof str, "%s%s%s", prefix, names.pci_path, names.bcma_core))
udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
if (names.pci_slot[0])
if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.bcma_core) < (int)sizeof(str))
if (names.pci_slot[0] &&
snprintf(str, sizeof str, "%s%s%s", prefix, names.pci_slot, names.bcma_core))
udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
goto out;
}