* [PATCH] usb: usbip: add NULL check after calloc()
@ 2026-09-02 7:09 longlong yan
2026-09-02 8:42 ` Greg KH
0 siblings, 1 reply; 3+ messages in thread
From: longlong yan @ 2026-09-02 7:09 UTC (permalink / raw)
To: valentina.manea.m; +Cc: shuah, skhan, i, linux-usb, linux-kernel, longlong yan
Two calloc() calls in the usbip driver lack NULL return checks, leading
to potential NULL pointer dereferences on allocation failure:
1. usbipd.c do_standalone_mode(): the allocated `fds` array is
immediately dereferenced in the following for-loop via fds[i].fd
without checking for NULL.
2. usbip_host_common.c usbip_exported_device_new(): the allocated
`edev` is immediately dereferenced via edev->sudev without checking
for NULL.
Add NULL checks after each calloc(), returning -1 in do_standalone_mode()
and using the existing goto err path in usbip_exported_device_new(),
consistent with the error handling already present in both functions.
Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
---
tools/usb/usbip/libsrc/usbip_host_common.c | 2 ++
tools/usb/usbip/src/usbipd.c | 4 ++++
2 files changed, 6 insertions(+)
diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
index 01599cb2fa7b..8ad367e09e78 100644
--- a/tools/usb/usbip/libsrc/usbip_host_common.c
+++ b/tools/usb/usbip/libsrc/usbip_host_common.c
@@ -71,6 +71,8 @@ struct usbip_exported_device *usbip_exported_device_new(
int i;
edev = calloc(1, sizeof(struct usbip_exported_device));
+ if (!edev)
+ goto err;
edev->sudev =
udev_device_new_from_syspath(udev_context, sdevpath);
diff --git a/tools/usb/usbip/src/usbipd.c b/tools/usb/usbip/src/usbipd.c
index 3e22b651c754..cc707dea2882 100644
--- a/tools/usb/usbip/src/usbipd.c
+++ b/tools/usb/usbip/src/usbipd.c
@@ -544,6 +544,10 @@ static int do_standalone_mode(int daemonize, int ipv4, int ipv6)
dbg("listening on %d address%s", nsockfd, (nsockfd == 1) ? "" : "es");
fds = calloc(nsockfd, sizeof(struct pollfd));
+ if (!fds) {
+ err("calloc for fds");
+ return -1;
+ }
for (i = 0; i < nsockfd; i++) {
fds[i].fd = sockfdlist[i];
fds[i].events = POLLIN;
--
2.43.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] usb: usbip: add NULL check after calloc()
2026-09-02 7:09 [PATCH] usb: usbip: add NULL check after calloc() longlong yan
@ 2026-09-02 8:42 ` Greg KH
2026-09-04 17:07 ` Shuah Khan
0 siblings, 1 reply; 3+ messages in thread
From: Greg KH @ 2026-09-02 8:42 UTC (permalink / raw)
To: longlong yan; +Cc: valentina.manea.m, shuah, skhan, i, linux-usb, linux-kernel
On Wed, Sep 02, 2026 at 03:09:31PM +0800, longlong yan wrote:
> Two calloc() calls in the usbip driver lack NULL return checks, leading
> to potential NULL pointer dereferences on allocation failure:
This is in userspace, not in the "driver".
And how do you get a failure for calloc() in userspace?
> 1. usbipd.c do_standalone_mode(): the allocated `fds` array is
> immediately dereferenced in the following for-loop via fds[i].fd
> without checking for NULL.
>
> 2. usbip_host_common.c usbip_exported_device_new(): the allocated
> `edev` is immediately dereferenced via edev->sudev without checking
> for NULL.
>
> Add NULL checks after each calloc(), returning -1 in do_standalone_mode()
> and using the existing goto err path in usbip_exported_device_new(),
> consistent with the error handling already present in both functions.
>
> Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
> ---
> tools/usb/usbip/libsrc/usbip_host_common.c | 2 ++
> tools/usb/usbip/src/usbipd.c | 4 ++++
> 2 files changed, 6 insertions(+)
>
> diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
> index 01599cb2fa7b..8ad367e09e78 100644
> --- a/tools/usb/usbip/libsrc/usbip_host_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_host_common.c
> @@ -71,6 +71,8 @@ struct usbip_exported_device *usbip_exported_device_new(
> int i;
>
> edev = calloc(1, sizeof(struct usbip_exported_device));
> + if (!edev)
> + goto err;
>
> edev->sudev =
> udev_device_new_from_syspath(udev_context, sdevpath);
> diff --git a/tools/usb/usbip/src/usbipd.c b/tools/usb/usbip/src/usbipd.c
> index 3e22b651c754..cc707dea2882 100644
> --- a/tools/usb/usbip/src/usbipd.c
> +++ b/tools/usb/usbip/src/usbipd.c
> @@ -544,6 +544,10 @@ static int do_standalone_mode(int daemonize, int ipv4, int ipv6)
> dbg("listening on %d address%s", nsockfd, (nsockfd == 1) ? "" : "es");
>
> fds = calloc(nsockfd, sizeof(struct pollfd));
> + if (!fds) {
> + err("calloc for fds");
> + return -1;
I don't think you tested this :(
You leak stuff here, right?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] usb: usbip: add NULL check after calloc()
2026-09-02 8:42 ` Greg KH
@ 2026-09-04 17:07 ` Shuah Khan
0 siblings, 0 replies; 3+ messages in thread
From: Shuah Khan @ 2026-09-04 17:07 UTC (permalink / raw)
To: Greg KH, longlong yan
Cc: valentina.manea.m, shuah, i, linux-usb, linux-kernel, Shuah Khan
On 9/2/26 02:42, Greg KH wrote:
> On Wed, Sep 02, 2026 at 03:09:31PM +0800, longlong yan wrote:
>> Two calloc() calls in the usbip driver lack NULL return checks, leading
>> to potential NULL pointer dereferences on allocation failure:
>
> This is in userspace, not in the "driver".
>
> And how do you get a failure for calloc() in userspace?
>
>> 1. usbipd.c do_standalone_mode(): the allocated `fds` array is
>> immediately dereferenced in the following for-loop via fds[i].fd
>> without checking for NULL.
>>
>> 2. usbip_host_common.c usbip_exported_device_new(): the allocated
>> `edev` is immediately dereferenced via edev->sudev without checking
>> for NULL.
>>
>> Add NULL checks after each calloc(), returning -1 in do_standalone_mode()
>> and using the existing goto err path in usbip_exported_device_new(),
>> consistent with the error handling already present in both functions.
>>
>> Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
>> ---
>> tools/usb/usbip/libsrc/usbip_host_common.c | 2 ++
>> tools/usb/usbip/src/usbipd.c | 4 ++++
>> 2 files changed, 6 insertions(+)
>>
>> diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
>> index 01599cb2fa7b..8ad367e09e78 100644
>> --- a/tools/usb/usbip/libsrc/usbip_host_common.c
>> +++ b/tools/usb/usbip/libsrc/usbip_host_common.c
>> @@ -71,6 +71,8 @@ struct usbip_exported_device *usbip_exported_device_new(
>> int i;
>>
>> edev = calloc(1, sizeof(struct usbip_exported_device));
>> + if (!edev)
>> + goto err;
>>
>> edev->sudev =
>> udev_device_new_from_syspath(udev_context, sdevpath);
>> diff --git a/tools/usb/usbip/src/usbipd.c b/tools/usb/usbip/src/usbipd.c
>> index 3e22b651c754..cc707dea2882 100644
>> --- a/tools/usb/usbip/src/usbipd.c
>> +++ b/tools/usb/usbip/src/usbipd.c
>> @@ -544,6 +544,10 @@ static int do_standalone_mode(int daemonize, int ipv4, int ipv6)
>> dbg("listening on %d address%s", nsockfd, (nsockfd == 1) ? "" : "es");
>>
>> fds = calloc(nsockfd, sizeof(struct pollfd));
>> + if (!fds) {
>> + err("calloc for fds");
>> + return -1;
>
> I don't think you tested this :(
>
> You leak stuff here, right?
>
Thank you Greg for the review.
longlong yan, I am very reluctant to take usbip patches without
solid evidence of a real bug that can be reproduced and the patch
fixes it.
I am seeing a few too many usbip patches these days that don't fix
any bugs.
thanks,
-- Shuah
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-09-02 7:09 [PATCH] usb: usbip: add NULL check after calloc() longlong yan
2026-09-02 8:42 ` Greg KH
2026-09-04 17:07 ` Shuah Khan
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