[PATCH] tty/vt: don't set font mappings on vc not supporting this

[PATCH] tty/vt: don't set font mappings on vc not supporting this

[Imre Deak]

We can call this function for a dummy console that doesn't support
setting the font mapping, which will result in a null ptr BUG. So check
for this case and return error for consoles w/o font mapping support.

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=59321
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/tty/vt/consolemap.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index 610b720..59b25e0 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/drivers/tty/vt/consolemap.c
@@ -539,6 +539,12 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
 
 	/* Save original vc_unipagdir_loc in case we allocate a new one */
 	p = *vc->vc_uni_pagedir_loc;
+
+	if (!p) {
+		err = -EINVAL;
+
+		goto out_unlock;
+	}
 	
 	if (p->refcount > 1) {
 		int j, k;
@@ -623,6 +629,7 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
 		set_inverse_transl(vc, p, i); /* Update inverse translations */
 	set_inverse_trans_unicode(vc, p);
 
+out_unlock:
 	console_unlock();
 	return err;
 }
-- 
1.8.4

Re: [PATCH 3.14 00/18] 3.14.52-stable review

[Greg Kroah-Hartman]

On Sat, Sep 12, 2015 at 04:37:51PM +0530, Sudip Mukherjee wrote:
> On Fri, Sep 11, 2015 at 03:49:18PM -0700, Greg Kroah-Hartman wrote:
> > This is the start of the stable review cycle for the 3.14.52 release.
> > There are 18 patches in this series, all will be posted as a response
> > to this one.  If anyone has any issues with these being applied, please
> > let me know.
> > 
> > Responses should be made by Sun Sep 13 22:46:12 UTC 2015.
> > Anything received after that time might be too late.
> 
> Compiled and booted on x86_32. dmesg showd:
> kmemleak: 47 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
> 
> /sys/kernel/debug/kmemleak showed lots of:
> unreferenced object 0xf3204fb0 (size 1024):
>  comm "setfont", pid 326, jiffies 4294897405 (age 2079.568s)
>  hex dump (first 32 bytes):
> 	a3 00 a0 25 92 25 b1 00 a2 00 a5 00 a9 00 ae 00 ...%.%..........
> 	c6 00 dd 00 e6 00 52 01 53 01 78 01 14 20 20 20  ......R.S.x..   
>  backtrace:
> 	[<c1637adc>] kmemleak_alloc+0x3c/0xa0
> 	[<c116845f>] kmem_cache_alloc_trace+0x9f/0x140
> 	[<c13d3caa>] set_inverse_trans_unicode.isra.0+0x10a/0x120
> 	[<c13d4672>] con_set_unimap+0x1b2/0x230
> 	[<c13cee27>] vt_ioctl+0x857/0x1020
> 	[<c13c40e3>] tty_ioctl+0x233/0xa40
> 	[<c1188e82>] do_vfs_ioctl+0x2e2/0x540
> 	[<c1189140>] SyS_ioctl+0x60/0x90
> 	[<c164f086>] sysenter_after_call+0x0/0x21
> 	[<ffffffff>] 0xffffffff
> 
> 9e326f78713a ("tty/vt: don't set font mappings on vc not supporting this")
> solved the error for me. 9e326f78713a is marked for stable also and it
> will not apply cleanly.

So this isn't a new thing at all, can you provide a backport that worked
for you so I can queue it up for the next round?

thanks,

greg k-h

[PATCH] tty/vt: don't set font mappings on vc not supporting this

[Sudip Mukherjee]

commit 9e326f78713a4421fe11afc2ddeac07698fac131 upstream

We can call this function for a dummy console that doesn't support
setting the font mapping, which will result in a null ptr BUG. So check
for this case and return error for consoles w/o font mapping support.

Cc: <stable@vger.kernel.org> # 3.14.x
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
---

backporting for the first time so not exactly sure if the format is ok.

 drivers/tty/vt/consolemap.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index 2978ca5..08d36e4 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/drivers/tty/vt/consolemap.c
@@ -540,6 +540,11 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
 
 	/* Save original vc_unipagdir_loc in case we allocate a new one */
 	p = (struct uni_pagedir *)*vc->vc_uni_pagedir_loc;
+
+	if (!p) {
+		err = -EINVAL;
+		goto out_unlock;
+	}
 	if (p->readonly) {
 		console_unlock();
 		return -EIO;
@@ -633,6 +638,7 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
 		set_inverse_transl(vc, p, i); /* Update inverse translations */
 	set_inverse_trans_unicode(vc, p);
 
+out_unlock:
 	console_unlock();
 	return err;
 }
-- 
1.9.1

Re: [PATCH] tty/vt: don't set font mappings on vc not supporting this

[Greg Kroah-Hartman]

On Sun, Sep 13, 2015 at 11:33:51AM +0530, Sudip Mukherjee wrote:
> commit 9e326f78713a4421fe11afc2ddeac07698fac131 upstream
> 
> We can call this function for a dummy console that doesn't support
> setting the font mapping, which will result in a null ptr BUG. So check
> for this case and return error for consoles w/o font mapping support.
> 
> Cc: <stable@vger.kernel.org> # 3.14.x
> Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
> ---
> 
> backporting for the first time so not exactly sure if the format is ok.

You need to keep the original authorship of the patch around, as well as
their signed-off-by information.  Also, you didn't backport it
identically:

> 
>  drivers/tty/vt/consolemap.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
> index 2978ca5..08d36e4 100644
> --- a/drivers/tty/vt/consolemap.c
> +++ b/drivers/tty/vt/consolemap.c
> @@ -540,6 +540,11 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
>  
>  	/* Save original vc_unipagdir_loc in case we allocate a new one */
>  	p = (struct uni_pagedir *)*vc->vc_uni_pagedir_loc;
> +
> +	if (!p) {
> +		err = -EINVAL;
> +		goto out_unlock;

The original has a blank line between these two lines, why not keep it?

I'll fix it up, but be a bit more careful next time please.

thanks,

greg k-h

Re: [PATCH] tty/vt: don't set font mappings on vc not supporting this

[Sudip Mukherjee]

On Sun, Sep 20, 2015 at 06:40:15PM -0700, Greg Kroah-Hartman wrote:
> On Sun, Sep 13, 2015 at 11:33:51AM +0530, Sudip Mukherjee wrote:
> > commit 9e326f78713a4421fe11afc2ddeac07698fac131 upstream
<snip> 
> > Cc: <stable@vger.kernel.org> # 3.14.x
> > Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
> > ---
> > 
> > backporting for the first time so not exactly sure if the format is ok.
> 
> You need to keep the original authorship of the patch around, as well as
> their signed-off-by information.  Also, you didn't backport it
> identically:
> 
<snip>
> > +
> > +	if (!p) {
> > +		err = -EINVAL;
> > +		goto out_unlock;
> 
> The original has a blank line between these two lines, why not keep it?
> 
> I'll fix it up, but be a bit more careful next time please.
Sure, next time you will have no complaints about this.

regards
sudip