From 4b3eb4d2c5fd4c8eb3ad31fa494d243a886a9702 Mon Sep 17 00:00:00 2001 From: Jes Sorensen Date: Mon, 7 Mar 2016 14:50:06 -0500 Subject: [PATCH] super1: Fix potential buffer overflows when copying cluster_name cmap_get_string() used to retrieve cluster_name does not restrict it's size. To prevent buffer overflows use the size of the destination buffer, not strlen() of the source, and null terminate the copied string. Fixes: 0aa2f15b ("mdadm: add the ability to change cluster name)" Reviewed-by: NeilBrown Signed-off-by: Jes Sorensen --- super1.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/super1.c b/super1.c index f8a35ac1..baa9a96e 100644 --- a/super1.c +++ b/super1.c @@ -2201,6 +2201,7 @@ add_internal_bitmap1(struct supertype *st, unsigned long long chunk = *chunkp; int room = 0; int creating = 0; + int len; struct mdp_superblock_1 *sb = st->sb; bitmap_super_t *bms = (bitmap_super_t*)(((char*)sb) + MAX_SB_SIZE); int uuid[4]; @@ -2326,9 +2327,11 @@ add_internal_bitmap1(struct supertype *st, if (st->nodes) sb->feature_map = __cpu_to_le32(__le32_to_cpu(sb->feature_map) | MD_FEATURE_BITMAP_VERSIONED); - if (st->cluster_name) - strncpy((char *)bms->cluster_name, - st->cluster_name, strlen(st->cluster_name)); + if (st->cluster_name) { + len = sizeof(bms->cluster_name); + strncpy((char *)bms->cluster_name, st->cluster_name, len); + bms->cluster_name[len - 1] = '\0'; + } *chunkp = chunk; return 1; @@ -2366,7 +2369,7 @@ static int write_bitmap1(struct supertype *st, int fd, enum bitmap_update update bitmap_super_t *bms = (bitmap_super_t*)(((char*)sb)+MAX_SB_SIZE); int rv = 0; void *buf; - int towrite, n; + int towrite, n, len; struct align_fd afd; unsigned int i = 0; unsigned long long total_bm_space, bm_space_per_node; @@ -2375,8 +2378,11 @@ static int write_bitmap1(struct supertype *st, int fd, enum bitmap_update update case NameUpdate: /* update cluster name */ if (st->cluster_name) { - memset((char *)bms->cluster_name, 0, sizeof(bms->cluster_name)); - strncpy((char *)bms->cluster_name, st->cluster_name, 64); + len = sizeof(bms->cluster_name); + memset((char *)bms->cluster_name, 0, len); + strncpy((char *)bms->cluster_name, + st->cluster_name, len); + bms->cluster_name[len - 1] = '\0'; } break; case NodeNumUpdate: -- 2.39.5