2021-09-16 19:16:25

by Ian Abbott

Subject: [PATCH] comedi: Fix memory leak in compat_insnlist()

`compat_insnlist()` handles the 32-bit version of the `COMEDI_INSNLIST`
ioctl (whenwhen `CONFIG_COMPAT` is enabled). It allocates memory to
temporarily hold an array of `struct comedi_insn` converted from the
32-bit version in user space. This memory is only being freed if there
is a fault while filling the array, otherwise it is leaked.

Add a call to `kfree()` to fix the leak.

Fixes: b8d47d881305 ("comedi: get rid of compat_alloc_user_space() mess in COMEDI_INSNLIST compat"
Cc: Al Viro <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: [email protected]
Cc: <[email protected]> # 5.13+
Signed-off-by: Ian Abbott <[email protected]>
---
N.B. Also need patches for 5.8+ from before comedi moved out of staging.
---
drivers/comedi/comedi_fops.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c
index df77b6bf5c64..763cea8418f8 100644
--- a/drivers/comedi/comedi_fops.c
+++ b/drivers/comedi/comedi_fops.c
@@ -3090,6 +3090,7 @@ static int compat_insnlist(struct file *file, unsigned long arg)
mutex_lock(&dev->mutex);
rc = do_insnlist_ioctl(dev, insns, insnlist32.n_insns, file);
mutex_unlock(&dev->mutex);
+ kfree(insns);
return rc;
}

--
2.33.0

2021-09-16 19:16:47

by Ian Abbott

Subject: [PATCH v2] comedi: Fix memory leak in compat_insnlist()

`compat_insnlist()` handles the 32-bit version of the `COMEDI_INSNLIST`
ioctl (whenwhen `CONFIG_COMPAT` is enabled). It allocates memory to
temporarily hold an array of `struct comedi_insn` converted from the
32-bit version in user space. This memory is only being freed if there
is a fault while filling the array, otherwise it is leaked.

Add a call to `kfree()` to fix the leak.

Fixes: b8d47d881305 ("comedi: get rid of compat_alloc_user_space() mess in COMEDI_INSNLIST compat"
Cc: Al Viro <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: [email protected]
Cc: <[email protected]> # 5.13+
Signed-off-by: Ian Abbott <[email protected]>
---
v2: Corrected typo in Greg's email address.

N.B. Also need patches for 5.8+ from before comedi moved out of staging.
---
drivers/comedi/comedi_fops.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c
index df77b6bf5c64..763cea8418f8 100644
--- a/drivers/comedi/comedi_fops.c
+++ b/drivers/comedi/comedi_fops.c
@@ -3090,6 +3090,7 @@ static int compat_insnlist(struct file *file, unsigned long arg)
mutex_lock(&dev->mutex);
rc = do_insnlist_ioctl(dev, insns, insnlist32.n_insns, file);
mutex_unlock(&dev->mutex);
+ kfree(insns);
return rc;
}

--
2.33.0