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authorJeremy Cline <jcline@redhat.com>2018-07-31 01:37:31 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-09-09 20:01:26 +0200
commit0515258e4776912b53a7772b208fc130837380fb (patch)
tree7598d23565d5d2690df6a69779b5130cded579c6
parentac617410962fcdd6b4675865a4469a8a54abb584 (diff)
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 <jpoimboe@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Jeremy Cline <jcline@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/quota/quota.c2
1 files changed, 2 insertions, 0 deletions
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 <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)
@@ -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.