Sergey Raevskiy <sergey.raevs...@visualsvn.com> writes:

> This happens beacuse lb.infos field is getting initialized only in function
> lock_body() (see the code below).  So, if svn_fs_fs__with_write_lock() fails
> without actual invoking the lock_body(), lb.infos will be left uninitialized.

[...]

> I've attached the patch with crashing test and simple fix for this issue.

Comments inline.

> @@ -1056,9 +1053,6 @@ unlock_body(void *baton, apr_pool_t *pool)
>    int i, max_components = 0, outstanding = 0;
>    apr_pool_t *iterpool = svn_pool_create(pool);
>
> -  ub->infos = apr_array_make(ub->result_pool, ub->targets->nelts,
> -                             sizeof(struct unlock_info_t));
> -
>    SVN_ERR(ub->fs->vtable->youngest_rev(&youngest, ub->fs, pool));
>    SVN_ERR(ub->fs->vtable->revision_root(&root, ub->fs, youngest, pool));

The unlock_body() function has multiple calling sites — svn_fs_fs__unlock()
and unlock_single().  This patch moves the ub->infos initialization into
svn_fs_fs__unlock(), but leaves unlock_single() unchanged.  Hence, we will
most likely see another segfault due to us accessing uninitialized memory:

  Use of uninitialised value of size 8
     at 0x59BA8D6: apr_array_push (...)
     by 0x6413D1B: unlock_body (lock.c:1089)
     by 0x6414BE6: get_lock (lock.c:1181)
     by 0x6412CD1: svn_fs_fs__allow_locked_operation (lock.c:511)
     by 0x642233B: commit_body (transaction.c:3251)
     by 0x6408E9B: with_lock (fs_fs.c:221)
     by 0x6422130: svn_fs_fs__commit (transaction.c:3613)
     by 0x6425E0D: svn_fs_fs__commit_txn (tree.c:2224)
     by 0x4019B4: lock_expiration (locks-test.c:659)
     by 0x4E3DB34: test_thread (svn_test_main.c:525)
     by 0x5BE1181: start_thread (pthread_create.c:312)
     by 0x5EF230C: clone (clone.S:111)

  Invalid write of size 8
     at 0x6413D1C: unlock_body (lock.c:1089)
     by 0x6414BE6: get_lock (lock.c:1181)
     by 0x6412CD1: svn_fs_fs__allow_locked_operation (lock.c:511)
     by 0x642233B: commit_body (transaction.c:3251)
     by 0x6408E9B: with_lock (fs_fs.c:221)
     by 0x6422130: svn_fs_fs__commit (transaction.c:3613)
     by 0x6425E0D: svn_fs_fs__commit_txn (tree.c:2224)
     by 0x4019B4: lock_expiration (locks-test.c:659)
     by 0x4E3DB34: test_thread (svn_test_main.c:525)
     by 0x5BE1181: start_thread (pthread_create.c:312)
     by 0x5EF230C: clone (clone.S:111)

> +  SVN_ERR(create_greek_fs(&fs, &newrev, "obtain-write-lock-failure-test",
> +                          opts, pool));
> +  SVN_ERR(svn_fs_create_access(&access, "bubba", pool));
> +  SVN_ERR(svn_fs_set_access(fs, access));

Should probably be named "test-obtain-write-lock-failure".

+  /* Make a read only 'write-lock' file.  This prevents any write operations
+     from being executed. */
+  
SVN_ERR(svn_io_set_file_read_only("obtain-write-lock-failure-test/write-lock",
+                                    TRUE, pool));

I suppose there is no reason to use ignore_enoent = TRUE here, right?  The
'write-lock' is always there and if it is not, the test shouldn't give a
false positive.


Regards,
Evgeny Kotkov

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