| Message ID | 3c7f8c47f361c46751629b44570657ef811d94d0.1585129842.git.ps@pks.im (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Support for transactions in `git-update-ref --stdin` | expand |
Patrick Steinhardt <ps@pks.im> writes: > When cleaning up a transaction that has no updates queued, then the > transaction's backend data will not have been allocated. We correctly > handle this for the packed backend, where the cleanup function checks > whether the backend data has been allocated at all -- if not, then there > is nothing to clean up. For the files backend we do not check this and > as a result will hit a segfault due to dereferencing a `NULL` pointer > when cleaning up such a transaction. > > Fix the issue by checking whether `backend_data` is set in the files > backend, too. > > Signed-off-by: Patrick Steinhardt <ps@pks.im> > --- > refs/files-backend.c | 20 +++++++++++--------- > 1 file changed, 11 insertions(+), 9 deletions(-) Makes sense. Will queue. Thanks. > > diff --git a/refs/files-backend.c b/refs/files-backend.c > index 561c33ac8a..6516c7bc8c 100644 > --- a/refs/files-backend.c > +++ b/refs/files-backend.c > @@ -2565,17 +2565,19 @@ static void files_transaction_cleanup(struct files_ref_store *refs, > } > } > > - if (backend_data->packed_transaction && > - ref_transaction_abort(backend_data->packed_transaction, &err)) { > - error("error aborting transaction: %s", err.buf); > - strbuf_release(&err); > + if (backend_data) { > + if (backend_data->packed_transaction && > + ref_transaction_abort(backend_data->packed_transaction, &err)) { > + error("error aborting transaction: %s", err.buf); > + strbuf_release(&err); > + } > + > + if (backend_data->packed_refs_locked) > + packed_refs_unlock(refs->packed_ref_store); > + > + free(backend_data); > } > > - if (backend_data->packed_refs_locked) > - packed_refs_unlock(refs->packed_ref_store); > - > - free(backend_data); > - > transaction->state = REF_TRANSACTION_CLOSED; > }
diff --git a/refs/files-backend.c b/refs/files-backend.c index 561c33ac8a..6516c7bc8c 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -2565,17 +2565,19 @@ static void files_transaction_cleanup(struct files_ref_store *refs, } } - if (backend_data->packed_transaction && - ref_transaction_abort(backend_data->packed_transaction, &err)) { - error("error aborting transaction: %s", err.buf); - strbuf_release(&err); + if (backend_data) { + if (backend_data->packed_transaction && + ref_transaction_abort(backend_data->packed_transaction, &err)) { + error("error aborting transaction: %s", err.buf); + strbuf_release(&err); + } + + if (backend_data->packed_refs_locked) + packed_refs_unlock(refs->packed_ref_store); + + free(backend_data); } - if (backend_data->packed_refs_locked) - packed_refs_unlock(refs->packed_ref_store); - - free(backend_data); - transaction->state = REF_TRANSACTION_CLOSED; }
When cleaning up a transaction that has no updates queued, then the transaction's backend data will not have been allocated. We correctly handle this for the packed backend, where the cleanup function checks whether the backend data has been allocated at all -- if not, then there is nothing to clean up. For the files backend we do not check this and as a result will hit a segfault due to dereferencing a `NULL` pointer when cleaning up such a transaction. Fix the issue by checking whether `backend_data` is set in the files backend, too. Signed-off-by: Patrick Steinhardt <ps@pks.im> --- refs/files-backend.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)