From: Simon Marchi <simark@simark.ca>
To: Jan Vrany <jan.vrany@labware.com>, gdb-patches@sourceware.org
Subject: Re: [PATCH] gdb: fix possible use-after-free when executing commands
Date: Wed, 14 Dec 2022 14:52:53 -0500 [thread overview]
Message-ID: <d23cf683-0a1a-c8ca-6288-8467a84af7c9@simark.ca> (raw)
In-Reply-To: <20221208142014.84759-1-jan.vrany@labware.com>
On 12/8/22 09:20, Jan Vrany via Gdb-patches wrote:
> In principle, `execute_command()` does following:
>
> struct cmd_list_element *c;
> c = lookup_cmd ( ... );
> ...
> /* If this command has been pre-hooked, run the hook first. */
> execute_cmd_pre_hook (c);
> ...
> /* ...execute the command `c` ...*/
> ...
> execute_cmd_post_hook (c);
>
> This may lead into use-after-free error. Imagine the command
> being executed is a user-defined Python command that redefines
> itself. In that case, struct `cmd_list_element` pointed to by
> `c` is deallocated during its execution so it is no longer valid
> when post hook is executed.
>
> To fix this case, this commit looks up the command once again
> after it is executed to get pointer to (possibly newly allocated)
> `cmd_list_element`.
Hi Jan,
Do you think you could write a test to exercise that fix?
Simon
next prev parent reply other threads:[~2022-12-14 19:52 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-08 14:20 Jan Vrany
2022-12-09 17:55 ` Tom Tromey
2022-12-12 15:05 ` Luis Machado
2022-12-12 15:08 ` Jan Vraný
2022-12-12 15:09 ` Luis Machado
2022-12-13 11:22 ` [PATCH] gdb: fix command lookup in execute_command () Jan Vrany
2022-12-13 15:05 ` Tom Tromey
2022-12-13 16:43 ` Simon Marchi
2022-12-13 18:48 ` Jan Vraný
2022-12-13 19:29 ` Simon Marchi
2022-12-14 11:07 ` [PATCH] gdb: fix command lookup in execute_command () commands" Jan Vrany
2022-12-14 15:35 ` Simon Marchi
2022-12-14 15:41 ` Jan Vraný
2022-12-14 15:59 ` Tom Tromey
2022-12-14 16:01 ` Simon Marchi
2022-12-14 18:05 ` Tom Tromey
2022-12-14 18:30 ` Simon Marchi
2022-12-14 22:01 ` Simon Marchi
2022-12-16 14:07 ` [PATCH] gdb: fix command lookup in execute_command () Jan Vraný
2022-12-16 16:47 ` Simon Marchi
2022-12-19 11:48 ` Jan Vraný
2022-12-19 14:46 ` Tom Tromey
2022-12-19 15:51 ` Jan Vraný
2022-12-20 19:10 ` Tom Tromey
2022-12-14 19:52 ` Simon Marchi [this message]
2022-12-14 20:39 ` [PATCH] gdb: fix possible use-after-free when executing commands Jan Vraný
2022-12-14 20:42 ` Simon Marchi
2022-12-15 12:57 ` Jan Vrany
2022-12-15 13:53 ` Simon Marchi
2022-12-15 14:51 ` Jan Vrany
2022-12-15 16:00 ` Simon Marchi
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