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Avoid memory leak if --args is specified multiple times #426

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Avoid memory leak if --args is specified multiple times #426

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6 changes: 6 additions & 0 deletions bubblewrap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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.

* a static analyzer which pointed out the memory leak
*/
if (opt_args_data != NULL)
free (opt_args_data);

/* opt_args_data is essentially a recursive argv array, which we must
* keep allocated until exit time, since its argv entries get used
* by the other cases in parse_args_recurse() when we recurse. */
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