Commit 283e7ad0 authored by Dan Ehrenberg's avatar Dan Ehrenberg Committed by Mike Snitzer

init: stricter checking of major:minor root= values

In the kernel command-line, previously, root=1:2jakshflaksjdhfa would
be accepted and interpreted just like root=1:2. This patch adds
stricter checking so that additional characters after major:minor are
rejected by root=.

The goal of this change is to help in unifying DM's interpretation of
its block device argument by using existing kernel code (name_to_dev_t).
But DM rejects malformed major:minor pairs, it seems reasonable for
root= to reject them as well.
Signed-off-by: default avatarDan Ehrenberg <>
Signed-off-by: default avatarMike Snitzer <>
parent e6e20a7a
......@@ -226,8 +226,9 @@ dev_t name_to_dev_t(const char *name)
if (strncmp(name, "/dev/", 5) != 0) {
unsigned maj, min;
char dummy;
if (sscanf(name, "%u:%u", &maj, &min) == 2) {
if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) {
res = MKDEV(maj, min);
if (maj != MAJOR(res) || min != MINOR(res))
goto fail;
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