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 98E9317C9; Tue, 17 Sep 2024 07:58:46 +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=1726559926; cv=none; b=ZZHf1Otcn1UFeTfJRPP+E6Ym2sq2G1N1Bwiy+Qixd0Pu/1PXmnqyxMP/1CO9IS2ytmU59dYG4dDnCsvpAU/cLNeetLddolN4ta7ni1y3XNXerueO8eVo38wvnOKYNsXuQiSfEqn8ZTiQF0HjVWCePqA1c49e/ujD0vDSN8X7wXs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726559926; c=relaxed/simple; bh=orsHV9E0EGGP6gcVrHvZUzHixcctY1Aw7voz/ReaRRg=; h=Date:To:From:Subject:Message-Id; b=CZZGK0bF/CwZE0fGIory2nNfhPE4W/8kLhjkPyRx1ObKmk4vkWRgt4w6tUzzeGWC2iL4CcVBxLMuaRmNEhalt/LUIk15PW59suyzG9xurY/FZZvac+Gpzz6lp3ZmNtXNYqxd+YB6nRWdPKKZIGsaDQL0NwgJK7P5F8vhORGgm8E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=rK5gfBot; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="rK5gfBot" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8BD14C4CEC6; Tue, 17 Sep 2024 07:58:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1726559926; bh=orsHV9E0EGGP6gcVrHvZUzHixcctY1Aw7voz/ReaRRg=; h=Date:To:From:Subject:From; b=rK5gfBotARCkl0LVUJ+KIyvbJJxYIhp5Ns678Smy3Xx1KNVd0yNINVKj06U2528sA fLQ7meI6JB/AW0jeAC8Hc76+MA8QT5KDaNv8dU+FbbNIOn93lDyszkxB+fIqXI+HaM dkcEz6f93+2yRPOXwy1EMIihImvBZiAeK1GplhxA= Date: Tue, 17 Sep 2024 00:58:42 -0700 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,muchun.song@linux.dev,vishal.moola@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-hugetlbc-fix-uaf-of-vma-in-hugetlb-fault-pathway.patch removed from -mm tree Message-Id: <20240917075845.8BD14C4CEC6@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/hugetlb.c: fix UAF of vma in hugetlb fault pathway has been removed from the -mm tree. Its filename was mm-hugetlbc-fix-uaf-of-vma-in-hugetlb-fault-pathway.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: "Vishal Moola (Oracle)" Subject: mm/hugetlb.c: fix UAF of vma in hugetlb fault pathway Date: Sat, 14 Sep 2024 12:41:19 -0700 Syzbot reports a UAF in hugetlb_fault(). This happens because vmf_anon_prepare() could drop the per-VMA lock and allow the current VMA to be freed before hugetlb_vma_unlock_read() is called. We can fix this by using a modified version of vmf_anon_prepare() that doesn't release the VMA lock on failure, and then release it ourselves after hugetlb_vma_unlock_read(). Link: https://lkml.kernel.org/r/20240914194243.245-2-vishal.moola@gmail.com Fixes: 9acad7ba3e25 ("hugetlb: use vmf_anon_prepare() instead of anon_vma_prepare()") Reported-by: syzbot+2dab93857ee95f2eeb08@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-mm/00000000000067c20b06219fbc26@google.com/ Signed-off-by: Vishal Moola (Oracle) Cc: Muchun Song Cc: Signed-off-by: Andrew Morton --- mm/hugetlb.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) --- a/mm/hugetlb.c~mm-hugetlbc-fix-uaf-of-vma-in-hugetlb-fault-pathway +++ a/mm/hugetlb.c @@ -6048,7 +6048,7 @@ retry_avoidcopy: * When the original hugepage is shared one, it does not have * anon_vma prepared. */ - ret = vmf_anon_prepare(vmf); + ret = __vmf_anon_prepare(vmf); if (unlikely(ret)) goto out_release_all; @@ -6247,7 +6247,7 @@ static vm_fault_t hugetlb_no_page(struct } if (!(vma->vm_flags & VM_MAYSHARE)) { - ret = vmf_anon_prepare(vmf); + ret = __vmf_anon_prepare(vmf); if (unlikely(ret)) goto out; } @@ -6378,6 +6378,14 @@ static vm_fault_t hugetlb_no_page(struct folio_unlock(folio); out: hugetlb_vma_unlock_read(vma); + + /* + * We must check to release the per-VMA lock. __vmf_anon_prepare() is + * the only way ret can be set to VM_FAULT_RETRY. + */ + if (unlikely(ret & VM_FAULT_RETRY)) + vma_end_read(vma); + mutex_unlock(&hugetlb_fault_mutex_table[hash]); return ret; @@ -6599,6 +6607,14 @@ out_ptl: } out_mutex: hugetlb_vma_unlock_read(vma); + + /* + * We must check to release the per-VMA lock. __vmf_anon_prepare() in + * hugetlb_wp() is the only way ret can be set to VM_FAULT_RETRY. + */ + if (unlikely(ret & VM_FAULT_RETRY)) + vma_end_read(vma); + mutex_unlock(&hugetlb_fault_mutex_table[hash]); /* * Generally it's safe to hold refcount during waiting page lock. But _ Patches currently in -mm which might be from vishal.moola@gmail.com are