'type' is user-controlled, so sanitize it after the bounds check to
avoid using it in speculative execution. This covers the following
potential gadgets detected with the help of smatch:
* fs/ext4/super.c:5741 ext4_quota_read() warn: potential spectre issue
'sb_dqopt(sb)->files' [r]
* fs/ext4/super.c:5778 ext4_quota_write() warn: potential spectre issue
'sb_dqopt(sb)->files' [r]
* fs/f2fs/super.c:1552 f2fs_quota_read() warn: potential spectre issue
'sb_dqopt(sb)->files' [r]
* fs/f2fs/super.c:1608 f2fs_quota_write() warn: potential spectre issue
'sb_dqopt(sb)->files' [r]
* fs/quota/dquot.c:412 mark_info_dirty() warn: potential spectre issue
'sb_dqopt(sb)->info' [w]
* fs/quota/dquot.c:933 dqinit_needed() warn: potential spectre issue
'dquots' [r]
* fs/quota/dquot.c:2112 dquot_commit_info() warn: potential spectre
issue 'dqopt->ops' [r]
* fs/quota/dquot.c:2362 vfs_load_quota_inode() warn: potential spectre
issue 'dqopt->files' [w] (local cap)
* fs/quota/dquot.c:2369 vfs_load_quota_inode() warn: potential spectre
issue 'dqopt->ops' [w] (local cap)
* fs/quota/dquot.c:2370 vfs_load_quota_inode() warn: potential spectre
issue 'dqopt->info' [w] (local cap)
* fs/quota/quota.c:110 quota_getfmt() warn: potential spectre issue
'sb_dqopt(sb)->info' [r]
* fs/quota/quota_v2.c:84 v2_check_quota_file() warn: potential spectre
issue 'quota_magics' [w]
* fs/quota/quota_v2.c:85 v2_check_quota_file() warn: potential spectre
issue 'quota_versions' [w]
* fs/quota/quota_v2.c:96 v2_read_file_info() warn: potential spectre
issue 'dqopt->info' [r]
* fs/quota/quota_v2.c:172 v2_write_file_info() warn: potential spectre
issue 'dqopt->info' [r]
Additionally, a quick inspection indicates there are array accesses with
'type' in quota_on() and quota_off() functions which are also addressed
by this.
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: sta...@vger.kernel.org
Signed-off-by: Jeremy Cline <jcl...@redhat.com>
---
This patch isn't going to cleanly apply to stable without the "fs/quota:
Replace XQM_MAXQUOTAS usage with MAXQUOTAS" patch, but I'm not sure that
patch is really stable material and XQM_MAXQUOTAS has been 3 since
pre-v4.4 so the end result will be the same even if that patch isn't
backported.
fs/quota/quota.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index d403392d8a0f..f0cbf58ad4da 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -18,6 +18,7 @@
#include <linux/quotaops.h>
#include <linux/types.h>
#include <linux/writeback.h>
+#include <linux/nospec.h>
static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
qid_t id)
@@ -701,6 +702,7 @@ static int do_quotactl(struct super_block *sb, int type,
int cmd, qid_t id,
if (type >= MAXQUOTAS)
return -EINVAL;
+ type = array_index_nospec(type, MAXQUOTAS);
/*
* Quota not supported on this fs? Check this before s_quota_types
* since they needn't be set if quota is not supported at all.
--
2.17.1
