From: Jason Cooper <jason@lakedaemon.net>
To: william.c.roberts@intel.com, Yann Droneaud <ydroneaud@opteya.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com
Cc: linux@arm.linux.org.uk, akpm@linux-foundation.org,
keescook@chromium.org, tytso@mit.edu, arnd@arndb.de,
gregkh@linuxfoundation.org, catalin.marinas@arm.com,
will.deacon@arm.com, ralf@linux-mips.org,
benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, x86@kernel.org, viro@zeniv.linux.org.uk,
nnk@google.com, jeffv@google.com, dcashman@android.com,
Jason Cooper <jason@lakedaemon.net>
Subject: [PATCH 1/7] random: Simplify API for random address requests
Date: Thu, 28 Jul 2016 20:47:24 +0000 [thread overview]
Message-ID: <20160728204730.27453-2-jason@lakedaemon.net> (raw)
In-Reply-To: <20160728204730.27453-1-jason@lakedaemon.net>
To date, all callers of randomize_range() have set the length to 0, and
check for a zero return value. For the current callers, the only way
to get zero returned is if end <= start. Since they are all adding a
constant to the start address, this is unnecessary.
We can remove a bunch of needless checks by simplifying the API to do
just what everyone wants, return an address between [start, start +
range).
While we're here, s/get_random_int/get_random_long/. No current call
site is adversely affected by get_random_int(), since all current range
requests are < UINT_MAX. However, we should match caller expectations
to avoid coming up short (ha!) in the future.
Address generation within [start, start + range) behavior is preserved.
All current callers to randomize_range() chose to use the start address
if randomize_range() failed. Therefore, we simplify things by just
returning the start address on error.
randomize_range() will be removed once all callers have been converted
over to randomize_addr().
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
---
drivers/char/random.c | 26 ++++++++++++++++++++++++++
include/linux/random.h | 1 +
2 files changed, 27 insertions(+)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 0158d3bff7e5..3610774bcc53 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1840,6 +1840,32 @@ randomize_range(unsigned long start, unsigned long end, unsigned long len)
return PAGE_ALIGN(get_random_int() % range + start);
}
+/**
+ * randomize_addr - Generate a random, page aligned address
+ * @start: The smallest acceptable address the caller will take.
+ * @range: The size of the area, starting at @start, within which the
+ * random address must fall.
+ *
+ * Before page alignment, the random address generated can be any value from
+ * @start, to @start + @range - 1 inclusive.
+ *
+ * If @start + @range would overflow, @range is capped.
+ *
+ * Return: A page aligned address within [start, start + range). On error,
+ * @start is returned.
+ */
+unsigned long
+randomize_addr(unsigned long start, unsigned long range)
+{
+ if (range == 0)
+ return start;
+
+ if (start > ULONG_MAX - range)
+ range = ULONG_MAX - start;
+
+ return PAGE_ALIGN(get_random_long() % range + start);
+}
+
/* Interface for in-kernel drivers of true hardware RNGs.
* Those devices may produce endless random bits and will be throttled
* when our pool is full.
diff --git a/include/linux/random.h b/include/linux/random.h
index e47e533742b5..f1ca2fa4c071 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -35,6 +35,7 @@ extern const struct file_operations random_fops, urandom_fops;
unsigned int get_random_int(void);
unsigned long get_random_long(void);
unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
+unsigned long randomize_addr(unsigned long start, unsigned long range);
u32 prandom_u32(void);
void prandom_bytes(void *buf, size_t nbytes);
--
2.9.2
WARNING: multiple messages have this Message-ID (diff)
From: Jason Cooper <jason@lakedaemon.net>
To: william.c.roberts@intel.com, Yann Droneaud <ydroneaud@opteya.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com
Cc: linux@arm.linux.org.uk, akpm@linux-foundation.org,
keescook@chromium.org, tytso@mit.edu, arnd@arndb.de,
gregkh@linuxfoundation.org, catalin.marinas@arm.com,
will.deacon@arm.com, ralf@linux-mips.org,
benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, x86@kernel.org, viro@zeniv.linux.org.uk,
nnk@google.com, jeffv@google.com, dcashman@android.com,
Jason Cooper <jason@lakedaemon.net>
Subject: [PATCH 1/7] random: Simplify API for random address requests
Date: Thu, 28 Jul 2016 20:47:24 +0000 [thread overview]
Message-ID: <20160728204730.27453-2-jason@lakedaemon.net> (raw)
In-Reply-To: <20160728204730.27453-1-jason@lakedaemon.net>
To date, all callers of randomize_range() have set the length to 0, and
check for a zero return value. For the current callers, the only way
to get zero returned is if end <= start. Since they are all adding a
constant to the start address, this is unnecessary.
We can remove a bunch of needless checks by simplifying the API to do
just what everyone wants, return an address between [start, start +
range).
While we're here, s/get_random_int/get_random_long/. No current call
site is adversely affected by get_random_int(), since all current range
requests are < UINT_MAX. However, we should match caller expectations
to avoid coming up short (ha!) in the future.
Address generation within [start, start + range) behavior is preserved.
All current callers to randomize_range() chose to use the start address
if randomize_range() failed. Therefore, we simplify things by just
returning the start address on error.
randomize_range() will be removed once all callers have been converted
over to randomize_addr().
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
---
drivers/char/random.c | 26 ++++++++++++++++++++++++++
include/linux/random.h | 1 +
2 files changed, 27 insertions(+)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 0158d3bff7e5..3610774bcc53 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1840,6 +1840,32 @@ randomize_range(unsigned long start, unsigned long end, unsigned long len)
return PAGE_ALIGN(get_random_int() % range + start);
}
+/**
+ * randomize_addr - Generate a random, page aligned address
+ * @start: The smallest acceptable address the caller will take.
+ * @range: The size of the area, starting at @start, within which the
+ * random address must fall.
+ *
+ * Before page alignment, the random address generated can be any value from
+ * @start, to @start + @range - 1 inclusive.
+ *
+ * If @start + @range would overflow, @range is capped.
+ *
+ * Return: A page aligned address within [start, start + range). On error,
+ * @start is returned.
+ */
+unsigned long
+randomize_addr(unsigned long start, unsigned long range)
+{
+ if (range == 0)
+ return start;
+
+ if (start > ULONG_MAX - range)
+ range = ULONG_MAX - start;
+
+ return PAGE_ALIGN(get_random_long() % range + start);
+}
+
/* Interface for in-kernel drivers of true hardware RNGs.
* Those devices may produce endless random bits and will be throttled
* when our pool is full.
diff --git a/include/linux/random.h b/include/linux/random.h
index e47e533742b5..f1ca2fa4c071 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -35,6 +35,7 @@ extern const struct file_operations random_fops, urandom_fops;
unsigned int get_random_int(void);
unsigned long get_random_long(void);
unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
+unsigned long randomize_addr(unsigned long start, unsigned long range);
u32 prandom_u32(void);
void prandom_bytes(void *buf, size_t nbytes);
--
2.9.2
--
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WARNING: multiple messages have this Message-ID (diff)
From: Jason Cooper <jason@lakedaemon.net>
To: william.c.roberts@intel.com, Yann Droneaud <ydroneaud@opteya.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com
Cc: linux@arm.linux.org.uk, akpm@linux-foundation.org,
keescook@chromium.org, tytso@mit.edu, arnd@arndb.de,
gregkh@linuxfoundation.org, catalin.marinas@arm.com,
will.deacon@arm.com, ralf@linux-mips.org,
benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, x86@kernel.org, viro@zeniv.linux.org.uk,
nnk@google.com, jeffv@google.com, dcashman@android.com,
Jason Cooper <jason@lakedaemon.net>
Subject: [kernel-hardening] [PATCH 1/7] random: Simplify API for random address requests
Date: Thu, 28 Jul 2016 20:47:24 +0000 [thread overview]
Message-ID: <20160728204730.27453-2-jason@lakedaemon.net> (raw)
In-Reply-To: <20160728204730.27453-1-jason@lakedaemon.net>
To date, all callers of randomize_range() have set the length to 0, and
check for a zero return value. For the current callers, the only way
to get zero returned is if end <= start. Since they are all adding a
constant to the start address, this is unnecessary.
We can remove a bunch of needless checks by simplifying the API to do
just what everyone wants, return an address between [start, start +
range).
While we're here, s/get_random_int/get_random_long/. No current call
site is adversely affected by get_random_int(), since all current range
requests are < UINT_MAX. However, we should match caller expectations
to avoid coming up short (ha!) in the future.
Address generation within [start, start + range) behavior is preserved.
All current callers to randomize_range() chose to use the start address
if randomize_range() failed. Therefore, we simplify things by just
returning the start address on error.
randomize_range() will be removed once all callers have been converted
over to randomize_addr().
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
---
drivers/char/random.c | 26 ++++++++++++++++++++++++++
include/linux/random.h | 1 +
2 files changed, 27 insertions(+)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 0158d3bff7e5..3610774bcc53 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1840,6 +1840,32 @@ randomize_range(unsigned long start, unsigned long end, unsigned long len)
return PAGE_ALIGN(get_random_int() % range + start);
}
+/**
+ * randomize_addr - Generate a random, page aligned address
+ * @start: The smallest acceptable address the caller will take.
+ * @range: The size of the area, starting at @start, within which the
+ * random address must fall.
+ *
+ * Before page alignment, the random address generated can be any value from
+ * @start, to @start + @range - 1 inclusive.
+ *
+ * If @start + @range would overflow, @range is capped.
+ *
+ * Return: A page aligned address within [start, start + range). On error,
+ * @start is returned.
+ */
+unsigned long
+randomize_addr(unsigned long start, unsigned long range)
+{
+ if (range == 0)
+ return start;
+
+ if (start > ULONG_MAX - range)
+ range = ULONG_MAX - start;
+
+ return PAGE_ALIGN(get_random_long() % range + start);
+}
+
/* Interface for in-kernel drivers of true hardware RNGs.
* Those devices may produce endless random bits and will be throttled
* when our pool is full.
diff --git a/include/linux/random.h b/include/linux/random.h
index e47e533742b5..f1ca2fa4c071 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -35,6 +35,7 @@ extern const struct file_operations random_fops, urandom_fops;
unsigned int get_random_int(void);
unsigned long get_random_long(void);
unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
+unsigned long randomize_addr(unsigned long start, unsigned long range);
u32 prandom_u32(void);
void prandom_bytes(void *buf, size_t nbytes);
--
2.9.2
next prev parent reply other threads:[~2016-07-28 21:25 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-28 20:47 [PATCH 0/7] char/random: Simplify random address requests Jason Cooper
2016-07-28 20:47 ` [kernel-hardening] " Jason Cooper
2016-07-28 20:47 ` Jason Cooper
2016-07-28 20:47 ` Jason Cooper [this message]
2016-07-28 20:47 ` [kernel-hardening] [PATCH 1/7] random: Simplify API for " Jason Cooper
2016-07-28 20:47 ` Jason Cooper
2016-07-29 8:59 ` Yann Droneaud
2016-07-29 8:59 ` [kernel-hardening] " Yann Droneaud
2016-07-29 8:59 ` Yann Droneaud
2016-07-29 18:20 ` Jason Cooper
2016-07-29 18:20 ` [kernel-hardening] " Jason Cooper
2016-07-29 18:20 ` Jason Cooper
2016-07-28 20:47 ` [PATCH 2/7] x86: Use simpler " Jason Cooper
2016-07-28 20:47 ` [kernel-hardening] " Jason Cooper
2016-07-28 20:47 ` Jason Cooper
2016-07-28 20:47 ` [PATCH 3/7] ARM: " Jason Cooper
2016-07-28 20:47 ` [kernel-hardening] " Jason Cooper
2016-07-28 20:47 ` Jason Cooper
2016-07-28 20:47 ` [PATCH 4/7] arm64: " Jason Cooper
2016-07-28 20:47 ` [kernel-hardening] " Jason Cooper
2016-07-28 20:47 ` Jason Cooper
2016-07-29 13:48 ` Will Deacon
2016-07-29 13:48 ` [kernel-hardening] " Will Deacon
2016-07-29 13:48 ` Will Deacon
2016-07-28 20:47 ` [PATCH 5/7] tile: " Jason Cooper
2016-07-28 20:47 ` [kernel-hardening] " Jason Cooper
2016-07-28 20:47 ` Jason Cooper
2016-07-28 20:47 ` [PATCH 6/7] unicore32: " Jason Cooper
2016-07-28 20:47 ` [kernel-hardening] " Jason Cooper
2016-07-28 20:47 ` Jason Cooper
2016-07-28 20:47 ` [PATCH 7/7] random: Remove unused randomize_range() Jason Cooper
2016-07-28 20:47 ` [kernel-hardening] " Jason Cooper
2016-07-28 20:47 ` Jason Cooper
2016-07-30 15:42 ` [PATCH v2 0/7] char/random: Simplify random address requests Jason Cooper
2016-07-30 15:42 ` [kernel-hardening] " Jason Cooper
2016-07-30 15:42 ` Jason Cooper
2016-07-30 15:42 ` [PATCH v2 1/7] random: Simplify API for " Jason Cooper
2016-07-30 15:42 ` [kernel-hardening] " Jason Cooper
2016-07-30 15:42 ` Jason Cooper
2016-07-31 16:46 ` Kees Cook
2016-07-31 16:46 ` [kernel-hardening] " Kees Cook
2016-07-31 16:46 ` Kees Cook
2016-07-31 20:56 ` Jason Cooper
2016-07-31 20:56 ` [kernel-hardening] " Jason Cooper
2016-07-31 20:56 ` Jason Cooper
2016-08-01 19:47 ` Kees Cook
2016-08-01 19:47 ` [kernel-hardening] " Kees Cook
2016-08-01 19:47 ` Kees Cook
2016-08-01 23:17 ` Jason Cooper
2016-08-01 23:17 ` [kernel-hardening] " Jason Cooper
2016-08-01 23:17 ` Jason Cooper
2016-08-02 3:35 ` [kernel-hardening] " Michael Ellerman
2016-08-02 3:35 ` Michael Ellerman
2016-08-02 3:35 ` Michael Ellerman
2016-08-03 18:42 ` Jason Cooper
2016-08-03 18:42 ` Jason Cooper
2016-08-03 18:42 ` Jason Cooper
2016-07-30 15:42 ` [PATCH v2 2/7] x86: Use simpler " Jason Cooper
2016-07-30 15:42 ` [kernel-hardening] " Jason Cooper
2016-07-30 15:42 ` Jason Cooper
2016-07-30 15:42 ` [PATCH v2 3/7] ARM: " Jason Cooper
2016-07-30 15:42 ` [kernel-hardening] " Jason Cooper
2016-07-30 15:42 ` Jason Cooper
2016-07-30 15:42 ` [PATCH v2 4/7] arm64: " Jason Cooper
2016-07-30 15:42 ` [kernel-hardening] " Jason Cooper
2016-07-30 15:42 ` Jason Cooper
2016-07-30 15:42 ` [PATCH v2 5/7] tile: " Jason Cooper
2016-07-30 15:42 ` [kernel-hardening] " Jason Cooper
2016-07-30 15:42 ` Jason Cooper
2016-07-30 15:42 ` [PATCH v2 6/7] unicore32: " Jason Cooper
2016-07-30 15:42 ` [kernel-hardening] " Jason Cooper
2016-07-30 15:42 ` Jason Cooper
2016-07-30 15:42 ` [PATCH v2 7/7] random: Remove unused randomize_range() Jason Cooper
2016-07-30 15:42 ` [kernel-hardening] " Jason Cooper
2016-07-30 15:42 ` Jason Cooper
2016-08-03 23:39 ` [PATCH v3 0/7] char/random: Simplify random address requests Jason Cooper
2016-08-03 23:39 ` [kernel-hardening] " Jason Cooper
2016-08-03 23:39 ` Jason Cooper
2016-08-03 23:39 ` [PATCH v3 1/7] random: Simplify API for " Jason Cooper
2016-08-03 23:39 ` [kernel-hardening] " Jason Cooper
2016-08-03 23:39 ` Jason Cooper
2016-08-04 12:47 ` Yann Droneaud
2016-08-04 12:47 ` [kernel-hardening] " Yann Droneaud
2016-08-04 12:47 ` Yann Droneaud
2016-08-03 23:39 ` [PATCH v3 2/7] x86: Use simpler " Jason Cooper
2016-08-03 23:39 ` [kernel-hardening] " Jason Cooper
2016-08-03 23:39 ` Jason Cooper
2016-08-03 23:39 ` [PATCH v3 3/7] ARM: " Jason Cooper
2016-08-03 23:39 ` [kernel-hardening] " Jason Cooper
2016-08-03 23:39 ` Jason Cooper
2016-08-03 23:39 ` [PATCH v3 4/7] arm64: " Jason Cooper
2016-08-03 23:39 ` [kernel-hardening] " Jason Cooper
2016-08-03 23:39 ` Jason Cooper
2016-08-03 23:39 ` [PATCH v3 5/7] tile: " Jason Cooper
2016-08-03 23:39 ` [kernel-hardening] " Jason Cooper
2016-08-03 23:39 ` Jason Cooper
2016-08-03 23:39 ` [PATCH v3 6/7] unicore32: " Jason Cooper
2016-08-03 23:39 ` [kernel-hardening] " Jason Cooper
2016-08-03 23:39 ` Jason Cooper
2016-08-03 23:39 ` [PATCH v3 7/7] random: Remove unused randomize_range() Jason Cooper
2016-08-03 23:39 ` [kernel-hardening] " Jason Cooper
2016-08-03 23:39 ` Jason Cooper
2016-08-03 23:48 ` Andrew Morton
2016-08-03 23:48 ` [kernel-hardening] " Andrew Morton
2016-08-03 23:48 ` Andrew Morton
2016-08-04 0:19 ` Jason Cooper
2016-08-04 0:19 ` [kernel-hardening] " Jason Cooper
2016-08-04 0:19 ` Jason Cooper
2016-08-04 2:41 ` [PATCH v3 0/7] char/random: Simplify random address requests Kees Cook
2016-08-04 2:41 ` [kernel-hardening] " Kees Cook
2016-08-04 2:41 ` Kees Cook
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