* [PATCH AUTOSEL 5.4 25/40] tomoyo: ignore data race while checking quota
[not found] <20210224125340.483162-1-sashal@kernel.org>
@ 2021-02-24 12:53 ` Sasha Levin
2021-02-24 12:53 ` [PATCH AUTOSEL 5.4 29/40] smackfs: restrict bytes count in smackfs write functions Sasha Levin
1 sibling, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2021-02-24 12:53 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Tetsuo Handa, syzbot, Sasha Levin, linux-security-module
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
[ Upstream commit 5797e861e402fff2bedce4ec8b7c89f4248b6073 ]
syzbot is reporting that tomoyo's quota check is racy [1]. But this check
is tolerant of some degree of inaccuracy. Thus, teach KCSAN to ignore
this data race.
[1] https://syzkaller.appspot.com/bug?id=999533deec7ba6337f8aa25d8bd1a4d5f7e50476
Reported-by: syzbot <syzbot+0789a72b46fd91431bd8@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/tomoyo/file.c | 16 ++++++++--------
security/tomoyo/network.c | 8 ++++----
security/tomoyo/util.c | 24 ++++++++++++------------
3 files changed, 24 insertions(+), 24 deletions(-)
diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c
index 86f7d1b90212a..966f80e4d77e6 100644
--- a/security/tomoyo/file.c
+++ b/security/tomoyo/file.c
@@ -362,14 +362,14 @@ static bool tomoyo_merge_path_acl(struct tomoyo_acl_info *a,
{
u16 * const a_perm = &container_of(a, struct tomoyo_path_acl, head)
->perm;
- u16 perm = *a_perm;
+ u16 perm = READ_ONCE(*a_perm);
const u16 b_perm = container_of(b, struct tomoyo_path_acl, head)->perm;
if (is_delete)
perm &= ~b_perm;
else
perm |= b_perm;
- *a_perm = perm;
+ WRITE_ONCE(*a_perm, perm);
return !perm;
}
@@ -437,7 +437,7 @@ static bool tomoyo_merge_mkdev_acl(struct tomoyo_acl_info *a,
{
u8 *const a_perm = &container_of(a, struct tomoyo_mkdev_acl,
head)->perm;
- u8 perm = *a_perm;
+ u8 perm = READ_ONCE(*a_perm);
const u8 b_perm = container_of(b, struct tomoyo_mkdev_acl, head)
->perm;
@@ -445,7 +445,7 @@ static bool tomoyo_merge_mkdev_acl(struct tomoyo_acl_info *a,
perm &= ~b_perm;
else
perm |= b_perm;
- *a_perm = perm;
+ WRITE_ONCE(*a_perm, perm);
return !perm;
}
@@ -517,14 +517,14 @@ static bool tomoyo_merge_path2_acl(struct tomoyo_acl_info *a,
{
u8 * const a_perm = &container_of(a, struct tomoyo_path2_acl, head)
->perm;
- u8 perm = *a_perm;
+ u8 perm = READ_ONCE(*a_perm);
const u8 b_perm = container_of(b, struct tomoyo_path2_acl, head)->perm;
if (is_delete)
perm &= ~b_perm;
else
perm |= b_perm;
- *a_perm = perm;
+ WRITE_ONCE(*a_perm, perm);
return !perm;
}
@@ -655,7 +655,7 @@ static bool tomoyo_merge_path_number_acl(struct tomoyo_acl_info *a,
{
u8 * const a_perm = &container_of(a, struct tomoyo_path_number_acl,
head)->perm;
- u8 perm = *a_perm;
+ u8 perm = READ_ONCE(*a_perm);
const u8 b_perm = container_of(b, struct tomoyo_path_number_acl, head)
->perm;
@@ -663,7 +663,7 @@ static bool tomoyo_merge_path_number_acl(struct tomoyo_acl_info *a,
perm &= ~b_perm;
else
perm |= b_perm;
- *a_perm = perm;
+ WRITE_ONCE(*a_perm, perm);
return !perm;
}
diff --git a/security/tomoyo/network.c b/security/tomoyo/network.c
index f9ff121d7e1eb..a89ed55d85d41 100644
--- a/security/tomoyo/network.c
+++ b/security/tomoyo/network.c
@@ -233,14 +233,14 @@ static bool tomoyo_merge_inet_acl(struct tomoyo_acl_info *a,
{
u8 * const a_perm =
&container_of(a, struct tomoyo_inet_acl, head)->perm;
- u8 perm = *a_perm;
+ u8 perm = READ_ONCE(*a_perm);
const u8 b_perm = container_of(b, struct tomoyo_inet_acl, head)->perm;
if (is_delete)
perm &= ~b_perm;
else
perm |= b_perm;
- *a_perm = perm;
+ WRITE_ONCE(*a_perm, perm);
return !perm;
}
@@ -259,14 +259,14 @@ static bool tomoyo_merge_unix_acl(struct tomoyo_acl_info *a,
{
u8 * const a_perm =
&container_of(a, struct tomoyo_unix_acl, head)->perm;
- u8 perm = *a_perm;
+ u8 perm = READ_ONCE(*a_perm);
const u8 b_perm = container_of(b, struct tomoyo_unix_acl, head)->perm;
if (is_delete)
perm &= ~b_perm;
else
perm |= b_perm;
- *a_perm = perm;
+ WRITE_ONCE(*a_perm, perm);
return !perm;
}
diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c
index eba0b3395851e..3e6be8ff9a396 100644
--- a/security/tomoyo/util.c
+++ b/security/tomoyo/util.c
@@ -1036,30 +1036,30 @@ bool tomoyo_domain_quota_is_ok(struct tomoyo_request_info *r)
if (ptr->is_deleted)
continue;
+ /*
+ * Reading perm bitmap might race with tomoyo_merge_*() because
+ * caller does not hold tomoyo_policy_lock mutex. But exceeding
+ * max_learning_entry parameter by a few entries does not harm.
+ */
switch (ptr->type) {
case TOMOYO_TYPE_PATH_ACL:
- perm = container_of(ptr, struct tomoyo_path_acl, head)
- ->perm;
+ data_race(perm = container_of(ptr, struct tomoyo_path_acl, head)->perm);
break;
case TOMOYO_TYPE_PATH2_ACL:
- perm = container_of(ptr, struct tomoyo_path2_acl, head)
- ->perm;
+ data_race(perm = container_of(ptr, struct tomoyo_path2_acl, head)->perm);
break;
case TOMOYO_TYPE_PATH_NUMBER_ACL:
- perm = container_of(ptr, struct tomoyo_path_number_acl,
- head)->perm;
+ data_race(perm = container_of(ptr, struct tomoyo_path_number_acl, head)
+ ->perm);
break;
case TOMOYO_TYPE_MKDEV_ACL:
- perm = container_of(ptr, struct tomoyo_mkdev_acl,
- head)->perm;
+ data_race(perm = container_of(ptr, struct tomoyo_mkdev_acl, head)->perm);
break;
case TOMOYO_TYPE_INET_ACL:
- perm = container_of(ptr, struct tomoyo_inet_acl,
- head)->perm;
+ data_race(perm = container_of(ptr, struct tomoyo_inet_acl, head)->perm);
break;
case TOMOYO_TYPE_UNIX_ACL:
- perm = container_of(ptr, struct tomoyo_unix_acl,
- head)->perm;
+ data_race(perm = container_of(ptr, struct tomoyo_unix_acl, head)->perm);
break;
case TOMOYO_TYPE_MANUAL_TASK_ACL:
perm = 0;
--
2.27.0
^ permalink raw reply related [flat|nested] 2+ messages in thread* [PATCH AUTOSEL 5.4 29/40] smackfs: restrict bytes count in smackfs write functions
[not found] <20210224125340.483162-1-sashal@kernel.org>
2021-02-24 12:53 ` [PATCH AUTOSEL 5.4 25/40] tomoyo: ignore data race while checking quota Sasha Levin
@ 2021-02-24 12:53 ` Sasha Levin
1 sibling, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2021-02-24 12:53 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sabyrzhan Tasbolatov, syzbot+a71a442385a0b2815497,
Casey Schaufler, Sasha Levin, linux-security-module
From: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
[ Upstream commit 7ef4c19d245f3dc233fd4be5acea436edd1d83d8 ]
syzbot found WARNINGs in several smackfs write operations where
bytes count is passed to memdup_user_nul which exceeds
GFP MAX_ORDER. Check count size if bigger than PAGE_SIZE.
Per smackfs doc, smk_write_net4addr accepts any label or -CIPSO,
smk_write_net6addr accepts any label or -DELETE. I couldn't find
any general rule for other label lengths except SMK_LABELLEN,
SMK_LONGLABEL, SMK_CIPSOMAX which are documented.
Let's constrain, in general, smackfs label lengths for PAGE_SIZE.
Although fuzzer crashes write to smackfs/netlabel on 0x400000 length.
Here is a quick way to reproduce the WARNING:
python -c "print('A' * 0x400000)" > /sys/fs/smackfs/netlabel
Reported-by: syzbot+a71a442385a0b2815497@syzkaller.appspotmail.com
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/smack/smackfs.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 9c4308077574c..5e75ff2e1b14f 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -1163,7 +1163,7 @@ static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
return -EPERM;
if (*ppos != 0)
return -EINVAL;
- if (count < SMK_NETLBLADDRMIN)
+ if (count < SMK_NETLBLADDRMIN || count > PAGE_SIZE - 1)
return -EINVAL;
data = memdup_user_nul(buf, count);
@@ -1423,7 +1423,7 @@ static ssize_t smk_write_net6addr(struct file *file, const char __user *buf,
return -EPERM;
if (*ppos != 0)
return -EINVAL;
- if (count < SMK_NETLBLADDRMIN)
+ if (count < SMK_NETLBLADDRMIN || count > PAGE_SIZE - 1)
return -EINVAL;
data = memdup_user_nul(buf, count);
@@ -1830,6 +1830,10 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
if (!smack_privileged(CAP_MAC_ADMIN))
return -EPERM;
+ /* Enough data must be present */
+ if (count == 0 || count > PAGE_SIZE)
+ return -EINVAL;
+
data = memdup_user_nul(buf, count);
if (IS_ERR(data))
return PTR_ERR(data);
@@ -2001,6 +2005,9 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
if (!smack_privileged(CAP_MAC_ADMIN))
return -EPERM;
+ if (count > PAGE_SIZE)
+ return -EINVAL;
+
data = memdup_user_nul(buf, count);
if (IS_ERR(data))
return PTR_ERR(data);
@@ -2088,6 +2095,9 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
if (!smack_privileged(CAP_MAC_ADMIN))
return -EPERM;
+ if (count > PAGE_SIZE)
+ return -EINVAL;
+
data = memdup_user_nul(buf, count);
if (IS_ERR(data))
return PTR_ERR(data);
@@ -2643,6 +2653,10 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
if (!smack_privileged(CAP_MAC_ADMIN))
return -EPERM;
+ /* Enough data must be present */
+ if (count == 0 || count > PAGE_SIZE)
+ return -EINVAL;
+
data = memdup_user_nul(buf, count);
if (IS_ERR(data))
return PTR_ERR(data);
@@ -2735,10 +2749,13 @@ static ssize_t smk_write_relabel_self(struct file *file, const char __user *buf,
return -EPERM;
/*
+ * No partial write.
* Enough data must be present.
*/
if (*ppos != 0)
return -EINVAL;
+ if (count == 0 || count > PAGE_SIZE)
+ return -EINVAL;
data = memdup_user_nul(buf, count);
if (IS_ERR(data))
--
2.27.0
^ permalink raw reply related [flat|nested] 2+ messages in thread