Horton

Re: Avoid incomplete copy string (src/backend/access/transam/xlog.c)

Fabrízio de Royes Mello <fabriziomello@gmail.com>

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From: Fabrízio de Royes Mello <fabriziomello@gmail.com>
To: Ranier Vilela <ranier.vf@gmail.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2024-06-24T00:08:47Z
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  1. Use safe string copy routine

On Sun, 23 Jun 2024 at 20:51 Ranier Vilela <ranier.vf@gmail.com> wrote:

> Hi.
>
> In src/include/access/xlogbackup.h, the field *name*
> has one byte extra to store null-termination.
>
> But, in the function *do_pg_backup_start*,
> I think that is a mistake in the line (8736):
>
> memcpy(state->name, backupidstr, strlen(backupidstr));
>
> memcpy with strlen does not copy the whole string.
> strlen returns the exact length of the string, without
> the null-termination.
>
> So, I think this can result in errors,
> like in the function *build_backup_content*
> (src/backend/access/transam/xlogbackup.c)
> Where *appendStringInfo* expects a string with null-termination.
>
> appendStringInfo(result, "LABEL: %s\n", state->name);
>
> To fix, copy strlen size plus one byte, to include the null-termination.
>

>
Doesn’t “sizeof” solve the problem? It take in account the null-termination
character.
Fabrízio de Royes Mello