Avoid memory leak if --args is specified multiple times #426
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Found by a static analyzer.
```
bubblewrap-0.4.1/bubblewrap.c:1500: overwrite_var: Overwriting "opt_args_data" in "opt_args_data = load_file_data(the_fd, &data_len)" leaks the storage that "opt_args_data" points to.
# 1498| * keep allocated until exit time, since its argv entries get used
# 1499| * by the other cases in parse_args_recurse() when we recurse. */
# 1500|-> opt_args_data = load_file_data (the_fd, &data_len);
# 1501| if (opt_args_data == NULL)
# 1502| die_with_error ("Can't read --args data");
```
smcv
requested changes
Jun 10, 2021
| @@ -1494,6 +1494,12 @@ parse_args_recurse (int *argcp, | |||
| if (argv[1][0] == 0 || endptr[0] != 0 || the_fd < 0) | |||
| die ("Invalid fd: %s", argv[1]); | |||
|
|
|||
| /* Specifying --args multiple times doesn't work; this just pacifies | |||
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The man page says it does, and that does seem to be true:
$ rmdir /tmp/a /tmp/b
$ printf '--dir\0/tmp/a\0' > a
$ printf '--dir\0/tmp/b\0' > b
$ bwrap --dev-bind / / --args 3 --args 4 ls /tmp 3<a 4<b
(output contains a and b)
So I think opt_args_data might need to become a linked list, or some other mechanism that keeps all of the arguments blobs referenced so that static analyzers know they are OK to "leak" once per process.
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Eeek. This is why we have code review! It looks like at least flatpak (the main user of --args) is only appending it once, and for some reason I convinced myself the code was only designed to run once, but you're clearly right.
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#428
and then will rework this to be a linked list or strv after that lands.
cgwalters
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Jun 10, 2021
The code supports this today, so test it. xref containers#426 where I thought it didn't.
cgwalters
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Jun 10, 2021
The code supports this today, so test it. xref containers#426 where I thought it didn't.
brandsimon
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Mar 19, 2023
The code supports this today, so test it. xref containers#426 where I thought it didn't.
CrackerCat
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Jul 31, 2024
The code supports this today, so test it. xref containers#426 where I thought it didn't.
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Found by a static analyzer.