From 0515258e4776912b53a7772b208fc130837380fb Mon Sep 17 00:00:00 2001 From: Jeremy Cline Date: Tue, 31 Jul 2018 01:37:31 +0000 Subject: fs/quota: Fix spectre gadget in do_quotactl commit 7b6924d94a60c6b8c1279ca003e8744e6cd9e8b1 upstream. '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 Cc: stable@vger.kernel.org Signed-off-by: Jeremy Cline Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/quota/quota.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/quota/quota.c b/fs/quota/quota.c index 2d445425aad7..a2329f7ec638 100644 --- a/fs/quota/quota.c +++ b/fs/quota/quota.c @@ -17,6 +17,7 @@ #include #include #include +#include static int check_quotactl_permission(struct super_block *sb, int type, int cmd, qid_t id) @@ -706,6 +707,7 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : 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. -- cgit v1.2.3