[PATCH] mdadm: block creation with long names
From: Blazej Kucman <hidden>
Date: 2021-12-03 14:31:34
Subsystem:
the rest · Maintainer:
Linus Torvalds
This fixes buffer overflows in create_mddev(). It prohibits creation with not supported names for DDF and native. For IMSM, mdadm will do silent cut to 16 later. Signed-off-by: Mariusz Tkaczyk <redacted> Signed-off-by: Blazej Kucman <redacted> --- mdadm.8.in | 5 +++++ mdadm.c | 9 ++++++++- mdadm.h | 5 +++++ 3 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/mdadm.8.in b/mdadm.8.in
index 28d773c2..68e100cb 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in@@ -2186,6 +2186,11 @@ is run, but will be created by .I udev once the array becomes active. +The max length md-device name is limited to 32 characters. +Different metadata types have more strict limitation +(like IMSM where only 16 characters are allowed). +For that reason, long name could be truncated or rejected, it depends on metadata policy. + As devices are added, they are checked to see if they contain RAID superblocks or filesystems. They are also checked to see if the variance in device size exceeds 1%.
diff --git a/mdadm.c b/mdadm.c
index 91e67467..26299b2e 100644
--- a/mdadm.c
+++ b/mdadm.c@@ -1359,9 +1359,16 @@ int main(int argc, char *argv[]) mdfd = open_mddev(devlist->devname, 1); if (mdfd < 0) exit(1); - } else + } else { + char *bname = basename(devlist->devname); + + if (strlen(bname) > MD_NAME_MAX) { + pr_err("Name %s is too long.\n", devlist->devname); + exit(1); + } /* non-existent device is OK */ mdfd = open_mddev(devlist->devname, 0); + } if (mdfd == -2) { pr_err("device %s exists but is not an md array.\n", devlist->devname); exit(1);
diff --git a/mdadm.h b/mdadm.h
index 54567396..c7268a71 100644
--- a/mdadm.h
+++ b/mdadm.h@@ -1880,3 +1880,8 @@ enum r0layout { #define INVALID_SECTORS 1 /* And another special number needed for --data_offset=variable */ #define VARIABLE_OFFSET 3 + +/** + * This is true for native and DDF, IMSM allows 16. + */ +#define MD_NAME_MAX 32
--
2.26.2