RFC8259 ("The JavaScript Object Notation (JSON) Data Interchange
Format") only specifies \", \\, \/, \b, \f, \n, \r, and \r as valid
two-character escape sequences. This does not include \', which is not
required in JSON because it exclusively uses double quotes as string
separators.

Solidus (/) may be escaped, but does not have to. Only reverse
solidus (\), double quotes ("), and the control characters have to be
escaped. Therefore, with this fix, bpftool correctly supports all valid
two-character escape sequences (but still does not support characters
that require multi-character escape sequences).

Witout this fix, attempting to load a JSON file generated by bpftool
using Python 3.10.6's default json.load() may fail with the error
"Invalid \escape" if the file contains the invalid escaped single
quote (\').

Signed-off-by: Luis Gerhorst <gerhorst@cs.fau.de>
---
 tools/bpf/bpftool/json_writer.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/tools/bpf/bpftool/json_writer.c b/tools/bpf/bpftool/json_writer.c
index 7fea83bedf48..bca5dd0a59e3 100644
--- a/tools/bpf/bpftool/json_writer.c
+++ b/tools/bpf/bpftool/json_writer.c
@@ -80,9 +80,6 @@ static void jsonw_puts(json_writer_t *self, const char *str)
 		case '"':
 			fputs("\\\"", self->out);
 			break;
-		case '\'':
-			fputs("\\\'", self->out);
-			break;
 		default:
 			putc(*str, self->out);
 		}
-- 
2.34.1

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Mon, 27 Feb 2023 16:08:54 +0100 you wrote:
> RFC8259 ("The JavaScript Object Notation (JSON) Data Interchange
> Format") only specifies \", \\, \/, \b, \f, \n, \r, and \r as valid
> two-character escape sequences. This does not include \', which is not
> required in JSON because it exclusively uses double quotes as string
> separators.
> 
> Solidus (/) may be escaped, but does not have to. Only reverse
> solidus (\), double quotes ("), and the control characters have to be
> escaped. Therefore, with this fix, bpftool correctly supports all valid
> two-character escape sequences (but still does not support characters
> that require multi-character escape sequences).
> 
> [...]

Here is the summary with links:
  - tools: bpftool: remove invalid \' json escape
    https://git.kernel.org/bpf/bpf-next/c/c679bbd611c0

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

2023-02-27 16:08 UTC+0100 ~ Luis Gerhorst <gerhorst@cs.fau.de>
> RFC8259 ("The JavaScript Object Notation (JSON) Data Interchange
> Format") only specifies \", \\, \/, \b, \f, \n, \r, and \r as valid
> two-character escape sequences. This does not include \', which is not
> required in JSON because it exclusively uses double quotes as string
> separators.
> 
> Solidus (/) may be escaped, but does not have to. Only reverse
> solidus (\), double quotes ("), and the control characters have to be
> escaped. Therefore, with this fix, bpftool correctly supports all valid
> two-character escape sequences (but still does not support characters
> that require multi-character escape sequences).
> 
> Witout this fix, attempting to load a JSON file generated by bpftool
> using Python 3.10.6's default json.load() may fail with the error
> "Invalid \escape" if the file contains the invalid escaped single
> quote (\').
> 
> Signed-off-by: Luis Gerhorst <gerhorst@cs.fau.de>

Fixes: b66e907cfee2 ("tools: bpftool: copy JSON writer from iproute2
repository")

I see this escape was similarly removed from iproute2's version of the
file [0]. Thanks!

Reviewed-by: Quentin Monnet <quentin@isovalent.com>

[0]
https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/commit/lib/json_writer.c?id=49c63bc775d610c3dfd3db0d6501ac29c519967f