From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BADB428DB5A; Wed, 7 May 2025 16:14:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746634453; cv=none; b=R7Hrj5ahkBh2sXSk/8HuYEfNW50Drn0qGChwR5pu8qxgaayYSdHPcgrR3/RPwzAHiJ+muRi4wWAKc1MVz99tGKX4IuueASQOHy6cpD+noZ9erEpvbP4wLwhdH1C6EzILFOhLYhh0f6bwvnBpWy7A0vMo/v+oiKF1c9l2vAeFLtk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746634453; c=relaxed/simple; bh=zXr47MrQD+Vjun97zqt40Q7EjbQ2mE5MbGB6SQwusWw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=j5NYp/p4JEGM1NgU4fQuWTSn2aOpjIyP8M5O1GquHuClhZDe9N8XM0uSchLwVTSl2NvRdDMrhzq6/Hanhin6e0sDNL5sYaQqkLhlMjYAzKZlEmQo9wCjJIyMBcDD+QhnVl7jQyRJFX0buwjE/dIo2xkD2b9o9D8JK9LZMY7LyQE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=i+kH5eYe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="i+kH5eYe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67B23C4CEF0; Wed, 7 May 2025 16:14:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746634453; bh=zXr47MrQD+Vjun97zqt40Q7EjbQ2mE5MbGB6SQwusWw=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=i+kH5eYem4nf1I3H3VgsaR4HySrOCoUzNfxThdOofk56Z1ASNkpmpQwkN+OoCUdEI 8YQcFnlFlRRAdMGGJlN32P4nD2KDJt71Gn6ExovEiCqrkUNdKiCgpt2W7LRwZSvJ7u Xsppg0qGbkKGhDjl0J+i4pq/lE3b4a+gi5c2ektEqszXdZAJNdgOjb1GLOSZ7qvp+T vTWaZ51rUdBMMw/cLFd7HwRjWq7m4AIAjh8BnDYHbagZvWj25bxptnVpUjkIOp3YIP v9zOZU+K9onLOKMvfOiq5VyIqtRgGJkjXhXN+MfYpnO+yVy7TDChUOT7UazXPkHxxM c5n8klxGGFTAw== From: Christian Brauner Date: Wed, 07 May 2025 18:13:39 +0200 Subject: [PATCH v4 06/11] coredump: validate socket name as it is written Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250507-work-coredump-socket-v4-6-af0ef317b2d0@kernel.org> References: <20250507-work-coredump-socket-v4-0-af0ef317b2d0@kernel.org> In-Reply-To: <20250507-work-coredump-socket-v4-0-af0ef317b2d0@kernel.org> To: Kuniyuki Iwashima , linux-fsdevel@vger.kernel.org, Jann Horn Cc: Eric Dumazet , Oleg Nesterov , "David S. Miller" , Alexander Viro , Daan De Meyer , David Rheinsberg , Jakub Kicinski , Jan Kara , Lennart Poettering , Luca Boccassi , Mike Yuan , Paolo Abeni , Simon Horman , =?utf-8?q?Zbigniew_J=C4=99drzejewski-Szmek?= , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Christian Brauner , Alexander Mikhalitsyn X-Mailer: b4 0.15-dev-c25d1 X-Developer-Signature: v=1; a=openpgp-sha256; l=1280; i=brauner@kernel.org; h=from:subject:message-id; bh=zXr47MrQD+Vjun97zqt40Q7EjbQ2mE5MbGB6SQwusWw=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWRIt219u/fdS+9ViW8m/szMu/BOKPT1TJeiNY+y14rdm ZCWtJK9sKOUhUGMi0FWTJHFod0kXG45T8Vmo0wNmDmsTCBDGLg4BWAiiZUM/1M4FqwzMDG9JrLb 3Iztz2TbZQatX/RmL+V24z4fK7xu/XuGf9asZ8UXzj+cmKYpZbV6d+b0afHZ3k16hZHBnAKaso3 MTAA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 In contrast to other parameters written into /proc/sys/kernel/core_pattern that never fail we can validate enabling the new AF_UNIX support. This is obviously racy as hell but it's always been that way. Signed-off-by: Christian Brauner --- fs/coredump.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index d61e15d855d2..0f00f77be988 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1200,10 +1200,21 @@ void validate_coredump_safety(void) static int proc_dostring_coredump(const struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { - int error = proc_dostring(table, write, buffer, lenp, ppos); + int error; + ssize_t retval; + char old_core_pattern[CORENAME_MAX_SIZE]; - if (!error) - validate_coredump_safety(); + retval = strscpy(old_core_pattern, core_pattern, CORENAME_MAX_SIZE); + + error = proc_dostring(table, write, buffer, lenp, ppos); + if (error) + return error; + if (core_pattern[0] == '@' && strcmp(core_pattern, "@linuxafsk/coredump.socket")) { + strscpy(core_pattern, old_core_pattern, retval + 1); + return -EINVAL; + } + + validate_coredump_safety(); return error; } -- 2.47.2