From: "Luís Henriques" <lhenriques@suse.de> To: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: ocfs2-devel@oss.oracle.com, linux-kernel@vger.kernel.org, Mark Fasheh <mark@fasheh.com>, Joel Becker <jlbec@evilplan.org>, Heming Zhao <heming.zhao@suse.com> Subject: Re: [PATCH] ocfs2: fix use-after-free when unmounting read-only filesystem Date: Mon, 22 May 2023 13:23:07 +0100 [thread overview] Message-ID: <87h6s47dxw.fsf@brahms.olymp> (raw) In-Reply-To: <a57047d6-8f57-3dde-f15f-b24f63d675cd@linux.alibaba.com> (Joseph Qi's message of "Mon, 22 May 2023 20:01:25 +0800") Joseph Qi <joseph.qi@linux.alibaba.com> writes: > On 5/22/23 6:25 PM, Luís Henriques wrote: >> It's trivial to trigger a use-after-free bug in the ocfs2 quotas code using >> fstest generic/452. After mounting a filesystem as read-only, quotas are > > generic/452 is for testing ext4 mounted with dax and ro. > But ocfs2 doesn't support dax yet. Right, but I think it's still useful to run the 'generic' test-suite in a filesystem. We can always find issues in the test itself or, in this case, a bug in the filesystem. >> suspended and ocfs2_mem_dqinfo is freed through ->ocfs2_local_free_info(). When >> unmounting the filesystem, an UAF access to the oinfo will eventually cause a >> crash. > > In ocfs2_fill_super(), it won't enable quota if is a readonly mount. > Do you mean remount as readonly? Yes, sorry. Instead of "mounting", the patch changelog should say "After remounting a filesystem as read-only..." Cheers, -- Luís > > Thanks, > Joseph > >> >> Cc: <stable@vger.kernel.org> >> Signed-off-by: Luís Henriques <lhenriques@suse.de> >> --- >> fs/ocfs2/super.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c >> index 0b0e6a132101..988d1c076861 100644 >> --- a/fs/ocfs2/super.c >> +++ b/fs/ocfs2/super.c >> @@ -952,8 +952,10 @@ static void ocfs2_disable_quotas(struct ocfs2_super *osb) >> for (type = 0; type < OCFS2_MAXQUOTAS; type++) { >> if (!sb_has_quota_loaded(sb, type)) >> continue; >> - oinfo = sb_dqinfo(sb, type)->dqi_priv; >> - cancel_delayed_work_sync(&oinfo->dqi_sync_work); >> + if (!sb_has_quota_suspended(sb, type)) { >> + oinfo = sb_dqinfo(sb, type)->dqi_priv; >> + cancel_delayed_work_sync(&oinfo->dqi_sync_work); >> + } >> inode = igrab(sb->s_dquot.files[type]); >> /* Turn off quotas. This will remove all dquot structures from >> * memory and so they will be automatically synced to global
WARNING: multiple messages have this Message-ID (diff)
From: "Luís Henriques via Ocfs2-devel" <ocfs2-devel@oss.oracle.com> To: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com Subject: Re: [Ocfs2-devel] [PATCH] ocfs2: fix use-after-free when unmounting read-only filesystem Date: Mon, 22 May 2023 13:23:07 +0100 [thread overview] Message-ID: <87h6s47dxw.fsf@brahms.olymp> (raw) In-Reply-To: <a57047d6-8f57-3dde-f15f-b24f63d675cd@linux.alibaba.com> (Joseph Qi's message of "Mon, 22 May 2023 20:01:25 +0800") Joseph Qi <joseph.qi@linux.alibaba.com> writes: > On 5/22/23 6:25 PM, Luís Henriques wrote: >> It's trivial to trigger a use-after-free bug in the ocfs2 quotas code using >> fstest generic/452. After mounting a filesystem as read-only, quotas are > > generic/452 is for testing ext4 mounted with dax and ro. > But ocfs2 doesn't support dax yet. Right, but I think it's still useful to run the 'generic' test-suite in a filesystem. We can always find issues in the test itself or, in this case, a bug in the filesystem. >> suspended and ocfs2_mem_dqinfo is freed through ->ocfs2_local_free_info(). When >> unmounting the filesystem, an UAF access to the oinfo will eventually cause a >> crash. > > In ocfs2_fill_super(), it won't enable quota if is a readonly mount. > Do you mean remount as readonly? Yes, sorry. Instead of "mounting", the patch changelog should say "After remounting a filesystem as read-only..." Cheers, -- Luís > > Thanks, > Joseph > >> >> Cc: <stable@vger.kernel.org> >> Signed-off-by: Luís Henriques <lhenriques@suse.de> >> --- >> fs/ocfs2/super.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c >> index 0b0e6a132101..988d1c076861 100644 >> --- a/fs/ocfs2/super.c >> +++ b/fs/ocfs2/super.c >> @@ -952,8 +952,10 @@ static void ocfs2_disable_quotas(struct ocfs2_super *osb) >> for (type = 0; type < OCFS2_MAXQUOTAS; type++) { >> if (!sb_has_quota_loaded(sb, type)) >> continue; >> - oinfo = sb_dqinfo(sb, type)->dqi_priv; >> - cancel_delayed_work_sync(&oinfo->dqi_sync_work); >> + if (!sb_has_quota_suspended(sb, type)) { >> + oinfo = sb_dqinfo(sb, type)->dqi_priv; >> + cancel_delayed_work_sync(&oinfo->dqi_sync_work); >> + } >> inode = igrab(sb->s_dquot.files[type]); >> /* Turn off quotas. This will remove all dquot structures from >> * memory and so they will be automatically synced to global _______________________________________________ Ocfs2-devel mailing list Ocfs2-devel@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-devel
next prev parent reply other threads:[~2023-05-22 12:25 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-05-22 10:25 [PATCH] ocfs2: fix use-after-free when unmounting read-only filesystem Luís Henriques 2023-05-22 10:25 ` [Ocfs2-devel] " Luís Henriques via Ocfs2-devel 2023-05-22 12:01 ` Joseph Qi 2023-05-22 12:01 ` [Ocfs2-devel] " Joseph Qi via Ocfs2-devel 2023-05-22 12:23 ` Luís Henriques [this message] 2023-05-22 12:23 ` Luís Henriques via Ocfs2-devel 2023-05-22 12:36 ` Heming Zhao via Ocfs2-devel 2023-05-22 12:36 ` Heming Zhao 2023-05-22 13:22 ` Luís Henriques 2023-05-22 13:22 ` [Ocfs2-devel] " Luís Henriques via Ocfs2-devel 2023-05-23 2:43 ` Joseph Qi 2023-05-23 2:43 ` [Ocfs2-devel] " Joseph Qi via Ocfs2-devel 2023-05-23 2:41 ` Joseph Qi 2023-05-23 2:41 ` [Ocfs2-devel] " Joseph Qi via Ocfs2-devel -- strict thread matches above, loose matches on Subject: below -- 2023-05-22 10:24 Luís Henriques 2023-05-22 10:21 Luís Henriques 2023-05-22 10:20 Luís Henriques
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