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 AC68D1D07AB; Wed, 2 Oct 2024 13:50:50 +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=1727877050; cv=none; b=dRI1xMHDbI0u1extNcm/0PTmaOs/DW4cBMtKogdhpHAYplFzrhtCd4tZYyxueufXPdFcdwomT5dmpsjJeS6bg4XpaPz0T/hG+yiyvbjrn2pJBcaUxdHq8d8StfY87iicbCOuXxqBV3xxkN4b/HQ7Bpyh2RcIKOhIQxL+HwBsljQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727877050; c=relaxed/simple; bh=7nqUFSmFGogcogKzJDST8dstwEUwH8tKa93Gj6kwJU0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ibo1OAbpO6PPCTnSquWsNOUGI31Tprz2hitwg3MPXNXzprvF4OGmcws2tGmmKNiCrGABAMEqHaeTKqB9O9bGUTNc73H1W40eDhh+WzxOjsFHrMzI+RFLPFEIU7IRC0LJyEZ1PsEDC6SvI1kyoWVf7wSWqaCdNBS2ESqSLIl9aXs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uBzuCPhG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="uBzuCPhG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33D63C4CECE; Wed, 2 Oct 2024 13:50:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727877050; bh=7nqUFSmFGogcogKzJDST8dstwEUwH8tKa93Gj6kwJU0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uBzuCPhGiQwvONMYDOyuusglNbqd4nyAORfQ5dByZfTOu2lNYXHwwSbhB89OD2R8U ShVU49fsIaVdfS5cN8ASx3kAP+wMDd4YlapjC4wmr6YKgxAb2VzrraVgVeUPhV2KPY 7zt0Qa9iox9q9ELm5wAcGTlRo9xzmMUfOtH7KoAs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Al Viro , Casey Schaufler , Christian Brauner , James Morris , Jann Horn , Ondrej Mosnacek , Paul Moore , "Serge E. Hallyn" , Stephen Smalley , =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= Subject: [PATCH 6.11 647/695] fs: Fix file_set_fowner LSM hook inconsistencies Date: Wed, 2 Oct 2024 15:00:45 +0200 Message-ID: <20241002125848.339941493@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241002125822.467776898@linuxfoundation.org> References: <20241002125822.467776898@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mickaël Salaün commit 26f204380a3c182e5adf1a798db0724d6111b597 upstream. The fcntl's F_SETOWN command sets the process that handle SIGIO/SIGURG for the related file descriptor. Before this change, the file_set_fowner LSM hook was always called, ignoring the VFS logic which may not actually change the process that handles SIGIO (e.g. TUN, TTY, dnotify), nor update the related UID/EUID. Moreover, because security_file_set_fowner() was called without lock (e.g. f_owner.lock), concurrent F_SETOWN commands could result to a race condition and inconsistent LSM states (e.g. SELinux's fown_sid) compared to struct fown_struct's UID/EUID. This change makes sure the LSM states are always in sync with the VFS state by moving the security_file_set_fowner() call close to the UID/EUID updates and using the same f_owner.lock . Rename f_modown() to __f_setown() to simplify code. Cc: stable@vger.kernel.org Cc: Al Viro Cc: Casey Schaufler Cc: Christian Brauner Cc: James Morris Cc: Jann Horn Cc: Ondrej Mosnacek Cc: Paul Moore Cc: Serge E. Hallyn Cc: Stephen Smalley Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Mickaël Salaün Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman --- fs/fcntl.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -87,8 +87,8 @@ static int setfl(int fd, struct file * f return error; } -static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, - int force) +void __f_setown(struct file *filp, struct pid *pid, enum pid_type type, + int force) { write_lock_irq(&filp->f_owner.lock); if (force || !filp->f_owner.pid) { @@ -98,19 +98,13 @@ static void f_modown(struct file *filp, if (pid) { const struct cred *cred = current_cred(); + security_file_set_fowner(filp); filp->f_owner.uid = cred->uid; filp->f_owner.euid = cred->euid; } } write_unlock_irq(&filp->f_owner.lock); } - -void __f_setown(struct file *filp, struct pid *pid, enum pid_type type, - int force) -{ - security_file_set_fowner(filp); - f_modown(filp, pid, type, force); -} EXPORT_SYMBOL(__f_setown); int f_setown(struct file *filp, int who, int force) @@ -146,7 +140,7 @@ EXPORT_SYMBOL(f_setown); void f_delown(struct file *filp) { - f_modown(filp, NULL, PIDTYPE_TGID, 1); + __f_setown(filp, NULL, PIDTYPE_TGID, 1); } pid_t f_getown(struct file *filp)