[LU-10767] Potential buffer overflow in lfs_setdirstripe Created: 05/Mar/18  Updated: 29/Jan/22  Resolved: 29/Jan/22

Status: Resolved
Project: Lustre
Component/s: None
Affects Version/s: Lustre 2.11.0
Fix Version/s: None

Type: Bug Priority: Minor
Reporter: Oleg Drokin Assignee: WC Triage
Resolution: Not a Bug Votes: 0
Labels: None

Issue Links:
Related
is related to LU-12624 DNE3: striped directory allocate stri... Resolved
is related to LU-10277 DNE3: allow 'lfs mkdir' to create dir... Resolved
Severity: 3
Rank (Obsolete): 9223372036854775807

 Description   

When we have more than 4000 MDTs, the code in lfs_setdirstripe will break:

                        if (auto_distributed) {
                                int r;
                                int nr = MAX(param->lsp_stripe_count,
                                             lsb->sb_count / 2);

                                /* don't use server whose usage is above 90% */
                                while (nr != param->lsp_stripe_count &&
                                       obd_statfs_ratio(&lsb->sb_buf[nr].sd_st)
                                       > 90)
                                        nr = MAX(param->lsp_stripe_count,
                                                 nr / 2);

                                /* get \a r between [0, nr) */
                                r = rand() % nr;

                                param->lsp_stripe_offset =
                                        lsb->sb_buf[r].sd_index;

but lsb->sb_buf is defined as 2000 elements (LL_STATFS_MAX->LOV_MAX_STRIPE_COUNT->2000)

This was introduced by https://review.whamcloud.com/30598

 Comments   
Comment by Andreas Dilger [ 29/Jan/22 ]

Code replaced in patch https://review.whamcloud.com/35825 "LU-12624 lod: alloc dir stripes by QoS"

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