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Message-Id: <1331597724-31358-45-git-send-email-paul.gortmaker@windriver.com>
Date: Mon, 12 Mar 2012 20:12:52 -0400
From: Paul Gortmaker <paul.gortmaker@...driver.com>
To: stable@...nel.org, linux-kernel@...r.kernel.org
Cc: stable-review@...nel.org, Dan Rosenberg <drosenberg@...curity.com>,
Takashi Iwai <tiwai@...e.de>,
Paul Gortmaker <paul.gortmaker@...driver.com>
Subject: [34-longterm 044/196] sound/oss: remove offset from load_patch callbacks
From: Dan Rosenberg <drosenberg@...curity.com>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------
commit b769f49463711205d57286e64cf535ed4daf59e9 upstream.
Was: [PATCH] sound/oss/midi_synth: prevent underflow, use of
uninitialized value, and signedness issue
The offset passed to midi_synth_load_patch() can be essentially
arbitrary. If it's greater than the header length, this will result in
a copy_from_user(dst, src, negative_val). While this will just return
-EFAULT on x86, on other architectures this may cause memory corruption.
Additionally, the length field of the sysex_info structure may not be
initialized prior to its use. Finally, a signed comparison may result
in an unintentionally large loop.
On suggestion by Takashi Iwai, version two removes the offset argument
from the load_patch callbacks entirely, which also resolves similar
issues in opl3. Compile tested only.
v3 adjusts comments and hopefully gets copy offsets right.
Signed-off-by: Dan Rosenberg <drosenberg@...curity.com>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---
sound/oss/dev_table.h | 2 +-
sound/oss/midi_synth.c | 30 +++++++++++++-----------------
sound/oss/midi_synth.h | 2 +-
sound/oss/opl3.c | 8 ++------
sound/oss/sequencer.c | 2 +-
5 files changed, 18 insertions(+), 26 deletions(-)
diff --git a/sound/oss/dev_table.h b/sound/oss/dev_table.h
index b7617be..0199a31 100644
--- a/sound/oss/dev_table.h
+++ b/sound/oss/dev_table.h
@@ -271,7 +271,7 @@ struct synth_operations
void (*reset) (int dev);
void (*hw_control) (int dev, unsigned char *event);
int (*load_patch) (int dev, int format, const char __user *addr,
- int offs, int count, int pmgr_flag);
+ int count, int pmgr_flag);
void (*aftertouch) (int dev, int voice, int pressure);
void (*controller) (int dev, int voice, int ctrl_num, int value);
void (*panning) (int dev, int voice, int value);
diff --git a/sound/oss/midi_synth.c b/sound/oss/midi_synth.c
index 3bc7104..11685f1 100644
--- a/sound/oss/midi_synth.c
+++ b/sound/oss/midi_synth.c
@@ -476,7 +476,7 @@ EXPORT_SYMBOL(midi_synth_hw_control);
int
midi_synth_load_patch(int dev, int format, const char __user *addr,
- int offs, int count, int pmgr_flag)
+ int count, int pmgr_flag)
{
int orig_dev = synth_devs[dev]->midi_dev;
@@ -491,33 +491,29 @@ midi_synth_load_patch(int dev, int format, const char __user *addr,
if (!prefix_cmd(orig_dev, 0xf0))
return 0;
+ /* Invalid patch format */
if (format != SYSEX_PATCH)
- {
-/* printk("MIDI Error: Invalid patch format (key) 0x%x\n", format);*/
return -EINVAL;
- }
+
+ /* Patch header too short */
if (count < hdr_size)
- {
-/* printk("MIDI Error: Patch header too short\n");*/
return -EINVAL;
- }
+
count -= hdr_size;
/*
- * Copy the header from user space but ignore the first bytes which have
- * been transferred already.
+ * Copy the header from user space
*/
- if(copy_from_user(&((char *) &sysex)[offs], &(addr)[offs], hdr_size - offs))
+ if (copy_from_user(&sysex, addr, hdr_size))
return -EFAULT;
-
- if (count < sysex.len)
- {
-/* printk(KERN_WARNING "MIDI Warning: Sysex record too short (%d<%d)\n", count, (int) sysex.len);*/
+
+ /* Sysex record too short */
+ if ((unsigned)count < (unsigned)sysex.len)
sysex.len = count;
- }
- left = sysex.len;
- src_offs = 0;
+
+ left = sysex.len;
+ src_offs = 0;
for (i = 0; i < left && !signal_pending(current); i++)
{
diff --git a/sound/oss/midi_synth.h b/sound/oss/midi_synth.h
index 6bc9d00..b64ddd6 100644
--- a/sound/oss/midi_synth.h
+++ b/sound/oss/midi_synth.h
@@ -8,7 +8,7 @@ int midi_synth_open (int dev, int mode);
void midi_synth_close (int dev);
void midi_synth_hw_control (int dev, unsigned char *event);
int midi_synth_load_patch (int dev, int format, const char __user * addr,
- int offs, int count, int pmgr_flag);
+ int count, int pmgr_flag);
void midi_synth_panning (int dev, int channel, int pressure);
void midi_synth_aftertouch (int dev, int channel, int pressure);
void midi_synth_controller (int dev, int channel, int ctrl_num, int value);
diff --git a/sound/oss/opl3.c b/sound/oss/opl3.c
index f4ffdff..407cd67 100644
--- a/sound/oss/opl3.c
+++ b/sound/oss/opl3.c
@@ -820,7 +820,7 @@ static void opl3_hw_control(int dev, unsigned char *event)
}
static int opl3_load_patch(int dev, int format, const char __user *addr,
- int offs, int count, int pmgr_flag)
+ int count, int pmgr_flag)
{
struct sbi_instrument ins;
@@ -830,11 +830,7 @@ static int opl3_load_patch(int dev, int format, const char __user *addr,
return -EINVAL;
}
- /*
- * What the fuck is going on here? We leave junk in the beginning
- * of ins and then check the field pretty close to that beginning?
- */
- if(copy_from_user(&((char *) &ins)[offs], addr + offs, sizeof(ins) - offs))
+ if (copy_from_user(&ins, addr, sizeof(ins)))
return -EFAULT;
if (ins.channel < 0 || ins.channel >= SBFM_MAXINSTR)
diff --git a/sound/oss/sequencer.c b/sound/oss/sequencer.c
index e85789e..a0072a9 100644
--- a/sound/oss/sequencer.c
+++ b/sound/oss/sequencer.c
@@ -241,7 +241,7 @@ int sequencer_write(int dev, struct file *file, const char __user *buf, int coun
return -ENXIO;
fmt = (*(short *) &event_rec[0]) & 0xffff;
- err = synth_devs[dev]->load_patch(dev, fmt, buf, p + 4, c, 0);
+ err = synth_devs[dev]->load_patch(dev, fmt, buf + p, c, 0);
if (err < 0)
return err;
--
1.7.9.3
--
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