CVE-2024-49912 - NULL Pointer Dereference

Severity

55%

Complexity

18%

Confidentiality

60%

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Handle null 'stream_status' in 'planes_changed_for_existing_stream' This commit adds a null check for 'stream_status' in the function 'planes_changed_for_existing_stream'. Previously, the code assumed 'stream_status' could be null, but did not handle the case where it was actually null. This could lead to a null pointer dereference. Reported by smatch: drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:3784 planes_changed_for_existing_stream() error: we previously assumed 'stream_status' could be null (see line 3774)

CVSS 3.1 Base Score 5.5. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

Demo Examples

NULL Pointer Dereference

CWE-476

While there are no complete fixes aside from conscientious programming, the following steps will go a long way to ensure that NULL pointer dereferences do not occur.


               
}
/* make use of pointer1 *//* ... */

If you are working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the if statement; and unlock when it has finished.

NULL Pointer Dereference

CWE-476

This example takes an IP address from a user, verifies that it is well formed and then looks up the hostname and copies it into a buffer.


               
}
strcpy(hostname, hp->h_name);/*routine that ensures user_supplied_addr is in the right format for conversion */

If an attacker provides an address that appears to be well-formed, but the address does not resolve to a hostname, then the call to gethostbyaddr() will return NULL. Since the code does not check the return value from gethostbyaddr (CWE-252), a NULL pointer dereference would then occur in the call to strcpy().

Note that this example is also vulnerable to a buffer overflow (see CWE-119).

NULL Pointer Dereference

CWE-476

In the following code, the programmer assumes that the system always has a property named "cmd" defined. If an attacker can control the program's environment so that "cmd" is not defined, the program throws a NULL pointer exception when it attempts to call the trim() method.


               
cmd = cmd.trim();

NULL Pointer Dereference

CWE-476

This application has registered to handle a URL when sent an intent:


               
}......
}
}
int length = URL.length();
...

The application assumes the URL will always be included in the intent. When the URL is not present, the call to getStringExtra() will return null, thus causing a null pointer exception when length() is called.

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