diff options
| -rw-r--r-- | block/sheepdog.c | 34 |
1 files changed, 22 insertions, 12 deletions
diff --git a/block/sheepdog.c b/block/sheepdog.c index 4742f8a..f35ff5b 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -866,14 +866,14 @@ static int parse_vdiname(BDRVSheepdogState *s, const char *filename, s->port = 0; } - strncpy(vdi, p, SD_MAX_VDI_LEN); + pstrcpy(vdi, SD_MAX_VDI_LEN, p); p = strchr(vdi, ':'); if (p) { *p++ = '\0'; *snapid = strtoul(p, NULL, 10); if (*snapid == 0) { - strncpy(tag, p, SD_MAX_VDI_TAG_LEN); + pstrcpy(tag, SD_MAX_VDI_TAG_LEN, p); } } else { *snapid = CURRENT_VDI_ID; /* search current vdi */ @@ -900,7 +900,10 @@ static int find_vdi_name(BDRVSheepdogState *s, char *filename, uint32_t snapid, return fd; } - memset(buf, 0, sizeof(buf)); + /* This pair of strncpy calls ensures that the buffer is zero-filled, + * which is desirable since we'll soon be sending those bytes, and + * don't want the send_req to read uninitialized data. + */ strncpy(buf, filename, SD_MAX_VDI_LEN); strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); @@ -1149,7 +1152,7 @@ static int sd_open(BlockDriverState *bs, const char *filename, int flags) s->max_dirty_data_idx = 0; bs->total_sectors = s->inode.vdi_size / SECTOR_SIZE; - strncpy(s->name, vdi, sizeof(s->name)); + pstrcpy(s->name, sizeof(s->name), vdi); qemu_co_mutex_init(&s->lock); g_free(buf); return 0; @@ -1177,8 +1180,11 @@ static int do_sd_create(char *filename, int64_t vdi_size, return fd; } + /* FIXME: would it be better to fail (e.g., return -EIO) when filename + * does not fit in buf? For now, just truncate and avoid buffer overrun. + */ memset(buf, 0, sizeof(buf)); - strncpy(buf, filename, SD_MAX_VDI_LEN); + pstrcpy(buf, sizeof(buf), filename); memset(&hdr, 0, sizeof(hdr)); hdr.opcode = SD_OP_NEW_VDI; @@ -1752,6 +1758,9 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) s->inode.vm_state_size = sn_info->vm_state_size; s->inode.vm_clock_nsec = sn_info->vm_clock_nsec; + /* It appears that inode.tag does not require a NUL terminator, + * which means this use of strncpy is ok. + */ strncpy(s->inode.tag, sn_info->name, sizeof(s->inode.tag)); /* we don't need to update entire object */ datalen = SD_INODE_SIZE - sizeof(s->inode.data_vdi_id); @@ -1811,13 +1820,13 @@ static int sd_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) memcpy(old_s, s, sizeof(BDRVSheepdogState)); - memset(vdi, 0, sizeof(vdi)); - strncpy(vdi, s->name, sizeof(vdi)); + pstrcpy(vdi, sizeof(vdi), s->name); - memset(tag, 0, sizeof(tag)); snapid = strtoul(snapshot_id, NULL, 10); - if (!snapid) { - strncpy(tag, s->name, sizeof(tag)); + if (snapid) { + tag[0] = 0; + } else { + pstrcpy(tag, sizeof(tag), s->name); } ret = find_vdi_name(s, vdi, snapid, tag, &vid, 1); @@ -1946,8 +1955,9 @@ static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab) snprintf(sn_tab[found].id_str, sizeof(sn_tab[found].id_str), "%u", inode.snap_id); - strncpy(sn_tab[found].name, inode.tag, - MIN(sizeof(sn_tab[found].name), sizeof(inode.tag))); + pstrcpy(sn_tab[found].name, + MIN(sizeof(sn_tab[found].name), sizeof(inode.tag)), + inode.tag); found++; } } |