Patchwork [hardy,maverick/ti-omap4,CVE,1/1] sound/oss: remove offset from load_patch callbacks

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Submitter Andy Whitcroft
Date Feb. 2, 2012, 10:14 a.m.
Message ID <1328177646-10163-2-git-send-email-apw@canonical.com>
Download mbox | patch
Permalink /patch/139104/
State New
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Comments

Andy Whitcroft - Feb. 2, 2012, 10:14 a.m.
From: Dan Rosenberg <drosenberg@vsecurity.com>

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@vsecurity.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

(cherry picked from commit b769f49463711205d57286e64cf535ed4daf59e9)
CVE-2011-1476
BugLink: http://bugs.launchpad.net/bugs/925337
Signed-off-by: Andy Whitcroft <apw@canonical.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(-)
Stefan Bader - Feb. 2, 2012, 10:32 a.m.
On 02.02.2012 11:14, Andy Whitcroft wrote:
> From: Dan Rosenberg <drosenberg@vsecurity.com>
> 
> 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@vsecurity.com>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> 
> (cherry picked from commit b769f49463711205d57286e64cf535ed4daf59e9)
> CVE-2011-1476
> BugLink: http://bugs.launchpad.net/bugs/925337
> Signed-off-by: Andy Whitcroft <apw@canonical.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 9e45098..f83f072 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 7781c13..6b5f54b 100644
> --- a/sound/oss/opl3.c
> +++ b/sound/oss/opl3.c
> @@ -819,7 +819,7 @@ 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;
>  
> @@ -829,11 +829,7 @@ 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 5c215f7..7027b8d 100644
> --- a/sound/oss/sequencer.c
> +++ b/sound/oss/sequencer.c
> @@ -242,7 +242,7 @@ 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;
>  
Roughly looks sane.

Acked-by: Stefan Bader <stefan.bader@canonical.com>
Herton Ronaldo Krzesinski - Feb. 2, 2012, 11:50 a.m.
On Thu, Feb 02, 2012 at 10:14:06AM +0000, Andy Whitcroft wrote:
> From: Dan Rosenberg <drosenberg@vsecurity.com>
> 
> 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@vsecurity.com>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> 
> (cherry picked from commit b769f49463711205d57286e64cf535ed4daf59e9)
> CVE-2011-1476
> BugLink: http://bugs.launchpad.net/bugs/925337
> Signed-off-by: Andy Whitcroft <apw@canonical.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 9e45098..f83f072 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 7781c13..6b5f54b 100644
> --- a/sound/oss/opl3.c
> +++ b/sound/oss/opl3.c
> @@ -819,7 +819,7 @@ 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;
>  
> @@ -829,11 +829,7 @@ 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 5c215f7..7027b8d 100644
> --- a/sound/oss/sequencer.c
> +++ b/sound/oss/sequencer.c
> @@ -242,7 +242,7 @@ 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;
>  
> -- 
> 1.7.8.3
> 
> 
> -- 
> kernel-team mailing list
> kernel-team@lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team
>

Patch

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 9e45098..f83f072 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 7781c13..6b5f54b 100644
--- a/sound/oss/opl3.c
+++ b/sound/oss/opl3.c
@@ -819,7 +819,7 @@  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;
 
@@ -829,11 +829,7 @@  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 5c215f7..7027b8d 100644
--- a/sound/oss/sequencer.c
+++ b/sound/oss/sequencer.c
@@ -242,7 +242,7 @@  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;