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[PATCH v2 1/5] test: firmware_class: report errors properly on failure

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  [PATCH v2 1/5] test: firmware_class: report errors properly on failure Brian Norris <computersforpeace@gmail.com> - 2015-12-10 00:00 +0100
    [PATCH v2 5/5] selftests: firmware: add empty string and async tests Brian Norris <computersforpeace@gmail.com> - 2015-12-10 00:00 +0100
    [PATCH v2 4/5] firmware: actually return NULL on failed request_firmware_nowait() Brian Norris <computersforpeace@gmail.com> - 2015-12-10 00:00 +0100
    [PATCH v2 2/5] test: firmware_class: use kstrndup() where appropriate Brian Norris <computersforpeace@gmail.com> - 2015-12-10 00:00 +0100

#1287962 — [PATCH v2 1/5] test: firmware_class: report errors properly on failure

request_firmware() failures currently won't get reported at all (the
error code is discarded). What's more, we get confusing messages, like:

    # echo -n notafile > /sys/devices/virtual/misc/test_firmware/trigger_request
    [ 8280.311856] test_firmware: loading 'notafile'
    [ 8280.317042] test_firmware: load of 'notafile' failed: -2
    [ 8280.322445] test_firmware: loaded: 0
    # echo $?
    0

Report the failures via write() errors, and don't say we "loaded"
anything.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
---
v2: no change

v1: thread starts here:
    https://lkml.org/lkml/2015/12/8/816

 lib/test_firmware.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lib/test_firmware.c b/lib/test_firmware.c
index 86374c1c49a4..841191061816 100644
--- a/lib/test_firmware.c
+++ b/lib/test_firmware.c
@@ -65,14 +65,19 @@ static ssize_t trigger_request_store(struct device *dev,
 	release_firmware(test_firmware);
 	test_firmware = NULL;
 	rc = request_firmware(&test_firmware, name, dev);
-	if (rc)
+	if (rc) {
 		pr_info("load of '%s' failed: %d\n", name, rc);
-	pr_info("loaded: %zu\n", test_firmware ? test_firmware->size : 0);
+		goto out;
+	}
+	pr_info("loaded: %zu\n", test_firmware->size);
+	rc = count;
+
+out:
 	mutex_unlock(&test_fw_mutex);
 
 	kfree(name);
 
-	return count;
+	return rc;
 }
 static DEVICE_ATTR_WO(trigger_request);
 
-- 
2.6.0.rc2.230.g3dd15c0

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#1287965 — [PATCH v2 5/5] selftests: firmware: add empty string and async tests

Now that we've added a 'trigger_async_request' knob to test the
request_firmware_nowait() API, let's use it. Also add tests for the
empty ("") string, since there have been a couple errors in that
handling already.

Since we now have real ways that the sysfs write might fail, let's add
the appropriate check on the 'echo' lines too.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
---
v2:
 * fix some spelling in commit message (wow, I wrote an atrocious sentence!)
 * use octal notation for printf, since the hex is non-POSIX and doesn't work
   in dash

 tools/testing/selftests/firmware/fw_filesystem.sh | 29 ++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/firmware/fw_filesystem.sh b/tools/testing/selftests/firmware/fw_filesystem.sh
index c4366dc74e01..5c495ad7958a 100755
--- a/tools/testing/selftests/firmware/fw_filesystem.sh
+++ b/tools/testing/selftests/firmware/fw_filesystem.sh
@@ -48,8 +48,21 @@ echo "ABCD0123" >"$FW"
 
 NAME=$(basename "$FW")
 
+if printf '\000' >"$DIR"/trigger_request; then
+	echo "$0: empty filename should not succeed" >&2
+	exit 1
+fi
+
+if printf '\000' >"$DIR"/trigger_async_request; then
+	echo "$0: empty filename should not succeed (async)" >&2
+	exit 1
+fi
+
 # Request a firmware that doesn't exist, it should fail.
-echo -n "nope-$NAME" >"$DIR"/trigger_request
+if echo -n "nope-$NAME" >"$DIR"/trigger_request; then
+	echo "$0: firmware shouldn't have loaded" >&2
+	exit 1
+fi
 if diff -q "$FW" /dev/test_firmware >/dev/null ; then
 	echo "$0: firmware was not expected to match" >&2
 	exit 1
@@ -74,4 +87,18 @@ else
 	echo "$0: filesystem loading works"
 fi
 
+# Try the asynchronous version too
+if ! echo -n "$NAME" >"$DIR"/trigger_async_request ; then
+	echo "$0: could not trigger async request" >&2
+	exit 1
+fi
+
+# Verify the contents are what we expect.
+if ! diff -q "$FW" /dev/test_firmware >/dev/null ; then
+	echo "$0: firmware was not loaded (async)" >&2
+	exit 1
+else
+	echo "$0: async filesystem loading works"
+fi
+
 exit 0
-- 
2.6.0.rc2.230.g3dd15c0

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#1287971 — [PATCH v2 4/5] firmware: actually return NULL on failed request_firmware_nowait()

The kerneldoc for request_firmware_nowait() says that it may call the
provided cont() callback with @fw == NULL, if the firmware request
fails. However, this is not the case when called with an empty string
(""). This case is short-circuited by the 'name[0] == '\0'' check
introduced in commit 471b095dfe0d ("firmware_class: make sure fw requests
contain a name"), so _request_firmware() never gets to set the fw to
NULL.

Noticed while using the new 'trigger_async_request' testing hook:

    # printf '\x00' > /sys/devices/virtual/misc/test_firmware/trigger_async_request
    [10553.726178] test_firmware: loading ''
    [10553.729859] test_firmware: loaded: 995209091
    # printf '\x00' > /sys/devices/virtual/misc/test_firmware/trigger_async_request
    [10733.676184] test_firmware: loading ''
    [10733.679855] Unable to handle kernel NULL pointer dereference at virtual address 00000004
    [10733.687951] pgd = ec188000
    [10733.690655] [00000004] *pgd=00000000
    [10733.694240] Internal error: Oops: 5 [#1] SMP ARM
    [10733.698847] Modules linked in: btmrvl_sdio btmrvl bluetooth sbs_battery nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables asix usbnet mwifiex_sdio mwifiex cfg80211 jitterentropy_rng drbg joydev snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device ppp_async ppp_generic slhc tun
    [10733.725670] CPU: 0 PID: 6600 Comm: bash Not tainted 4.4.0-rc4-00351-g63d0877 #178
    [10733.733137] Hardware name: Rockchip (Device Tree)
    [10733.737831] task: ed24f6c0 ti: ee322000 task.ti: ee322000
    [10733.743222] PC is at do_raw_spin_lock+0x18/0x1a0
    [10733.747831] LR is at _raw_spin_lock+0x18/0x1c
    [10733.752180] pc : [<c00653a0>]    lr : [<c054c204>]    psr: a00d0013
    [10733.752180] sp : ee323df8  ip : ee323e20  fp : ee323e1c
    [10733.763634] r10: 00000051  r9 : b6f18000  r8 : ee323f80
    [10733.768847] r7 : c089cebc  r6 : 00000001  r5 : 00000000  r4 : ec0e6000
    [10733.775360] r3 : dead4ead  r2 : c06bd140  r1 : eef913b4  r0 : 00000000
    [10733.781874] Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
    [10733.788995] Control: 10c5387d  Table: 2c18806a  DAC: 00000051
    [10733.794728] Process bash (pid: 6600, stack limit = 0xee322218)
    [10733.800549] Stack: (0xee323df8 to 0xee324000)
    [10733.804896] 3de0:                                                       ec0e6000 00000000
    [10733.813059] 3e00: 00000001 c089cebc ee323f80 b6f18000 ee323e2c ee323e20 c054c204 c0065394
    [10733.821221] 3e20: ee323e44 ee323e30 c02fec60 c054c1f8 ec0e7ec0 ec3fcfc0 ee323e5c ee323e48
    [10733.829384] 3e40: c02fed08 c02fec48 c07dbf74 eeb05a00 ee323e8c ee323e60 c0253828 c02fecac
    [10733.837547] 3e60: 00000001 c0116950 ee323eac ee323e78 00000001 ec3fce00 ed2d9700 ed2d970c
    [10733.845710] 3e80: ee323e9c ee323e90 c02e873c c02537d4 ee323eac ee323ea0 c017bd40 c02e8720
    [10733.853873] 3ea0: ee323ee4 ee323eb0 c017b250 c017bd00 00000000 00000000 f3e47a54 ec128b00
    [10733.862035] 3ec0: c017b10c ee323f80 00000001 c000f504 ee322000 00000000 ee323f4c ee323ee8
    [10733.870197] 3ee0: c011b71c c017b118 ee323fb0 c011bc90 becfa8d9 00000001 ec128b00 00000001
    [10733.878359] 3f00: b6f18000 ee323f80 ee323f4c ee323f18 c011bc90 c0063950 ee323f3c ee323f28
    [10733.886522] 3f20: c0063950 c0549138 00000001 ec128b00 00000001 ec128b00 b6f18000 ee323f80
    [10733.894684] 3f40: ee323f7c ee323f50 c011bed8 c011b6ec c0135fb8 c0135f24 ec128b00 ec128b00
    [10733.902847] 3f60: 00000001 b6f18000 c000f504 ee322000 ee323fa4 ee323f80 c011c664 c011be24
    [10733.911009] 3f80: 00000000 00000000 00000001 b6f18000 b6e79be0 00000004 00000000 ee323fa8
    [10733.919172] 3fa0: c000f340 c011c618 00000001 b6f18000 00000001 b6f18000 00000001 00000000
    [10733.927334] 3fc0: 00000001 b6f18000 b6e79be0 00000004 00000001 00000001 8068a3f1 b6e79c84
    [10733.935496] 3fe0: 00000000 becfa7dc b6de194d b6e20246 400d0030 00000001 7a4536e8 49bda390
    [10733.943664] [<c00653a0>] (do_raw_spin_lock) from [<c054c204>] (_raw_spin_lock+0x18/0x1c)
    [10733.951743] [<c054c204>] (_raw_spin_lock) from [<c02fec60>] (fw_free_buf+0x24/0x64)
    [10733.959388] [<c02fec60>] (fw_free_buf) from [<c02fed08>] (release_firmware+0x68/0x74)
    [10733.967207] [<c02fed08>] (release_firmware) from [<c0253828>] (trigger_async_request_store+0x60/0x124)
    [10733.976501] [<c0253828>] (trigger_async_request_store) from [<c02e873c>] (dev_attr_store+0x28/0x34)
    [10733.985533] [<c02e873c>] (dev_attr_store) from [<c017bd40>] (sysfs_kf_write+0x4c/0x58)
    [10733.993437] [<c017bd40>] (sysfs_kf_write) from [<c017b250>] (kernfs_fop_write+0x144/0x1a8)
    [10734.001689] [<c017b250>] (kernfs_fop_write) from [<c011b71c>] (__vfs_write+0x3c/0xe4)

After this patch:

    # printf '\x00' > /sys/devices/virtual/misc/test_firmware/trigger_async_request
    [   32.126322] test_firmware: loading ''
    [   32.129995] test_firmware: failed to async load firmware
    -bash: printf: write error: No such device

Fixes: 471b095dfe0d ("firmware_class: make sure fw requests contain a name")
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
---
v2: no change

 drivers/base/firmware_class.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 8524450e75bd..b9250e564ebf 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -1118,15 +1118,17 @@ static int
 _request_firmware(const struct firmware **firmware_p, const char *name,
 		  struct device *device, unsigned int opt_flags)
 {
-	struct firmware *fw;
+	struct firmware *fw = NULL;
 	long timeout;
 	int ret;
 
 	if (!firmware_p)
 		return -EINVAL;
 
-	if (!name || name[0] == '\0')
-		return -EINVAL;
+	if (!name || name[0] == '\0') {
+		ret = -EINVAL;
+		goto out;
+	}
 
 	ret = _request_firmware_prepare(&fw, name, device);
 	if (ret <= 0) /* error or already assigned */
-- 
2.6.0.rc2.230.g3dd15c0

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#1287973 — [PATCH v2 2/5] test: firmware_class: use kstrndup() where appropriate

We're essentially just doing an open-coded kstrndup(). The only
differences are with what happens after the first '\0' character, but
request_firmware() doesn't care about that.

Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
New in v2

 lib/test_firmware.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/test_firmware.c b/lib/test_firmware.c
index 841191061816..690b9c35a274 100644
--- a/lib/test_firmware.c
+++ b/lib/test_firmware.c
@@ -54,10 +54,9 @@ static ssize_t trigger_request_store(struct device *dev,
 	int rc;
 	char *name;
 
-	name = kzalloc(count + 1, GFP_KERNEL);
+	name = kstrndup(buf, count, GFP_KERNEL);
 	if (!name)
 		return -ENOSPC;
-	memcpy(name, buf, count);
 
 	pr_info("loading '%s'\n", name);
 
-- 
2.6.0.rc2.230.g3dd15c0

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