From ced5fa8b170ad448f4076e24a10c731b5cfb36ce Mon Sep 17 00:00:00 2001 From: Blazej Kucman Date: Fri, 3 Dec 2021 15:31:15 +0100 Subject: [PATCH] mdadm: block creation with long names 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 Signed-off-by: Blazej Kucman Signed-off-by: Jes Sorensen --- 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 28d773c..68e100c 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 91e6746..26299b2 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 5456739..c7268a7 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